From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 14:02:58 +0200
Subject: Adding upstream version 1.64.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../ch20-web-server/listing-20-01/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-01/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-01/src/main.rs      | 11 +++
 .../ch20-web-server/listing-20-02/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-02/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-02/src/main.rs      | 25 ++++++
 .../ch20-web-server/listing-20-03/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-03/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-03/src/main.rs      | 29 +++++++
 .../ch20-web-server/listing-20-05/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-05/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-05/hello.html       | 11 +++
 .../ch20-web-server/listing-20-05/src/main.rs      | 38 +++++++++
 .../ch20-web-server/listing-20-06/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-06/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-06/hello.html       | 11 +++
 .../ch20-web-server/listing-20-06/src/main.rs      | 37 +++++++++
 .../ch20-web-server/listing-20-07/404.html         | 11 +++
 .../ch20-web-server/listing-20-07/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-07/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-07/hello.html       | 11 +++
 .../ch20-web-server/listing-20-07/src/main.rs      | 45 ++++++++++
 .../ch20-web-server/listing-20-09/404.html         | 11 +++
 .../ch20-web-server/listing-20-09/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-09/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-09/hello.html       | 11 +++
 .../ch20-web-server/listing-20-09/src/main.rs      | 40 +++++++++
 .../ch20-web-server/listing-20-10/404.html         | 11 +++
 .../ch20-web-server/listing-20-10/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-10/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-10/hello.html       | 11 +++
 .../ch20-web-server/listing-20-10/src/main.rs      | 52 ++++++++++++
 .../ch20-web-server/listing-20-11/404.html         | 11 +++
 .../ch20-web-server/listing-20-11/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-11/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-11/hello.html       | 11 +++
 .../ch20-web-server/listing-20-11/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-12/404.html         | 11 +++
 .../ch20-web-server/listing-20-12/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-12/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-12/hello.html       | 11 +++
 .../ch20-web-server/listing-20-12/output.txt       | 10 +++
 .../ch20-web-server/listing-20-12/src/main.rs      | 44 ++++++++++
 .../ch20-web-server/listing-20-13/404.html         | 11 +++
 .../ch20-web-server/listing-20-13/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-13/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-13/hello.html       | 11 +++
 .../ch20-web-server/listing-20-13/src/lib.rs       | 27 ++++++
 .../ch20-web-server/listing-20-13/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-14/404.html         | 11 +++
 .../ch20-web-server/listing-20-14/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-14/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-14/hello.html       | 11 +++
 .../ch20-web-server/listing-20-14/src/lib.rs       | 40 +++++++++
 .../ch20-web-server/listing-20-14/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-15/404.html         | 11 +++
 .../ch20-web-server/listing-20-15/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-15/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-15/hello.html       | 11 +++
 .../ch20-web-server/listing-20-15/src/lib.rs       | 53 ++++++++++++
 .../ch20-web-server/listing-20-15/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-16/404.html         | 11 +++
 .../ch20-web-server/listing-20-16/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-16/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-16/hello.html       | 11 +++
 .../ch20-web-server/listing-20-16/src/lib.rs       | 58 +++++++++++++
 .../ch20-web-server/listing-20-16/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-17/404.html         | 11 +++
 .../ch20-web-server/listing-20-17/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-17/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-17/hello.html       | 11 +++
 .../ch20-web-server/listing-20-17/output.txt       | 13 +++
 .../ch20-web-server/listing-20-17/src/lib.rs       | 65 +++++++++++++++
 .../ch20-web-server/listing-20-17/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-18/404.html         | 11 +++
 .../ch20-web-server/listing-20-18/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-18/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-18/hello.html       | 11 +++
 .../ch20-web-server/listing-20-18/src/lib.rs       | 76 +++++++++++++++++
 .../ch20-web-server/listing-20-18/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-19/404.html         | 11 +++
 .../ch20-web-server/listing-20-19/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-19/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-19/hello.html       | 11 +++
 .../ch20-web-server/listing-20-19/src/lib.rs       | 69 ++++++++++++++++
 .../ch20-web-server/listing-20-19/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-20/404.html         | 11 +++
 .../ch20-web-server/listing-20-20/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-20/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-20/hello.html       | 11 +++
 .../ch20-web-server/listing-20-20/src/lib.rs       | 68 ++++++++++++++++
 .../ch20-web-server/listing-20-20/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-21/404.html         | 11 +++
 .../ch20-web-server/listing-20-21/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-21/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-21/hello.html       | 11 +++
 .../ch20-web-server/listing-20-21/src/lib.rs       | 67 +++++++++++++++
 .../ch20-web-server/listing-20-21/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-22/404.html         | 11 +++
 .../ch20-web-server/listing-20-22/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-22/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-22/hello.html       | 11 +++
 .../ch20-web-server/listing-20-22/output.txt       | 14 ++++
 .../ch20-web-server/listing-20-22/src/lib.rs       | 76 +++++++++++++++++
 .../ch20-web-server/listing-20-22/src/main.rs      | 43 ++++++++++
 .../ch20-web-server/listing-20-23/404.html         | 11 +++
 .../ch20-web-server/listing-20-23/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-23/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-23/hello.html       | 11 +++
 .../ch20-web-server/listing-20-23/src/lib.rs       | 95 ++++++++++++++++++++++
 .../ch20-web-server/listing-20-23/src/main.rs      | 45 ++++++++++
 .../ch20-web-server/listing-20-24/404.html         | 11 +++
 .../ch20-web-server/listing-20-24/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-24/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-24/hello.html       | 11 +++
 .../ch20-web-server/listing-20-24/src/lib.rs       | 92 +++++++++++++++++++++
 .../ch20-web-server/listing-20-24/src/main.rs      | 45 ++++++++++
 .../ch20-web-server/listing-20-25/404.html         | 11 +++
 .../ch20-web-server/listing-20-25/Cargo.lock       |  6 ++
 .../ch20-web-server/listing-20-25/Cargo.toml       |  6 ++
 .../ch20-web-server/listing-20-25/hello.html       | 11 +++
 .../ch20-web-server/listing-20-25/src/lib.rs       | 92 +++++++++++++++++++++
 .../ch20-web-server/listing-20-25/src/main.rs      | 53 ++++++++++++
 .../404.html                                       | 11 +++
 .../Cargo.lock                                     |  6 ++
 .../Cargo.toml                                     |  6 ++
 .../hello.html                                     | 11 +++
 .../output.txt                                     | 10 +++
 .../src/lib.rs                                     |  1 +
 .../src/main.rs                                    | 45 ++++++++++
 .../no-listing-02-impl-threadpool-new/404.html     | 11 +++
 .../no-listing-02-impl-threadpool-new/Cargo.lock   |  6 ++
 .../no-listing-02-impl-threadpool-new/Cargo.toml   |  6 ++
 .../no-listing-02-impl-threadpool-new/hello.html   | 11 +++
 .../no-listing-02-impl-threadpool-new/output.txt   | 10 +++
 .../no-listing-02-impl-threadpool-new/src/lib.rs   |  7 ++
 .../no-listing-02-impl-threadpool-new/src/main.rs  | 43 ++++++++++
 .../no-listing-03-define-execute/404.html          | 11 +++
 .../no-listing-03-define-execute/Cargo.lock        |  6 ++
 .../no-listing-03-define-execute/Cargo.toml        |  6 ++
 .../no-listing-03-define-execute/hello.html        | 11 +++
 .../no-listing-03-define-execute/output.txt        |  3 +
 .../no-listing-03-define-execute/src/lib.rs        | 18 ++++
 .../no-listing-03-define-execute/src/main.rs       | 43 ++++++++++
 .../404.html                                       | 11 +++
 .../Cargo.lock                                     |  6 ++
 .../Cargo.toml                                     |  6 ++
 .../hello.html                                     | 11 +++
 .../output.txt                                     | 24 ++++++
 .../src/lib.rs                                     | 76 +++++++++++++++++
 .../src/main.rs                                    | 43 ++++++++++
 .../no-listing-05-fix-worker-new/404.html          | 11 +++
 .../no-listing-05-fix-worker-new/Cargo.lock        |  6 ++
 .../no-listing-05-fix-worker-new/Cargo.toml        |  6 ++
 .../no-listing-05-fix-worker-new/hello.html        | 11 +++
 .../no-listing-05-fix-worker-new/src/lib.rs        | 83 +++++++++++++++++++
 .../no-listing-05-fix-worker-new/src/main.rs       | 43 ++++++++++
 .../no-listing-06-fix-threadpool-drop/404.html     | 11 +++
 .../no-listing-06-fix-threadpool-drop/Cargo.lock   |  6 ++
 .../no-listing-06-fix-threadpool-drop/Cargo.toml   |  6 ++
 .../no-listing-06-fix-threadpool-drop/hello.html   | 11 +++
 .../no-listing-06-fix-threadpool-drop/src/lib.rs   | 81 ++++++++++++++++++
 .../no-listing-06-fix-threadpool-drop/src/main.rs  | 45 ++++++++++
 .../no-listing-07-final-code/404.html              | 11 +++
 .../no-listing-07-final-code/Cargo.lock            |  6 ++
 .../no-listing-07-final-code/Cargo.toml            |  6 ++
 .../no-listing-07-final-code/hello.html            | 11 +++
 .../no-listing-07-final-code/src/lib.rs            | 92 +++++++++++++++++++++
 .../no-listing-07-final-code/src/main.rs           | 51 ++++++++++++
 169 files changed, 3502 insertions(+)
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-01/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-02/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-03/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-05/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-05/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-06/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-06/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-07/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-07/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-07/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-09/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-09/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-09/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-10/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-10/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-10/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-11/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-11/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-11/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-12/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-13/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-14/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-15/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-16/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-17/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-18/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-19/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-20/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-21/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-22/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-23/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-24/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/listing-20-25/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/output.txt
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/main.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/404.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.lock
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.toml
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/hello.html
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/lib.rs
 create mode 100644 src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/main.rs

(limited to 'src/doc/book/listings/ch20-web-server')

diff --git a/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-01/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-01/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-01/src/main.rs
new file mode 100644
index 000000000..d868c3ec1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-01/src/main.rs
@@ -0,0 +1,11 @@
+use std::net::TcpListener;
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        println!("Connection established!");
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-02/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-02/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-02/src/main.rs
new file mode 100644
index 000000000..7240c73c7
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-02/src/main.rs
@@ -0,0 +1,25 @@
+use std::{
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let http_request: Vec<_> = buf_reader
+        .lines()
+        .map(|result| result.unwrap())
+        .take_while(|line| !line.is_empty())
+        .collect();
+
+    println!("Request: {:#?}", http_request);
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-03/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-03/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-03/src/main.rs
new file mode 100644
index 000000000..c72d4a9c6
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-03/src/main.rs
@@ -0,0 +1,29 @@
+use std::{
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+
+// ANCHOR: here
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let http_request: Vec<_> = buf_reader
+        .lines()
+        .map(|result| result.unwrap())
+        .take_while(|line| !line.is_empty())
+        .collect();
+
+    let response = "HTTP/1.1 200 OK\r\n\r\n";
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-05/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-05/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-05/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-05/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-05/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-05/src/main.rs
new file mode 100644
index 000000000..d4b78b640
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-05/src/main.rs
@@ -0,0 +1,38 @@
+// ANCHOR: here
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+// --snip--
+
+// ANCHOR_END: here
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+
+// ANCHOR: here
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let http_request: Vec<_> = buf_reader
+        .lines()
+        .map(|result| result.unwrap())
+        .take_while(|line| !line.is_empty())
+        .collect();
+
+    let status_line = "HTTP/1.1 200 OK";
+    let contents = fs::read_to_string("hello.html").unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-06/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-06/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-06/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-06/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-06/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-06/src/main.rs
new file mode 100644
index 000000000..5523a42d7
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-06/src/main.rs
@@ -0,0 +1,37 @@
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+// ANCHOR: here
+// --snip--
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    if request_line == "GET / HTTP/1.1" {
+        let status_line = "HTTP/1.1 200 OK";
+        let contents = fs::read_to_string("hello.html").unwrap();
+        let length = contents.len();
+
+        let response = format!(
+            "{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}"
+        );
+
+        stream.write_all(response.as_bytes()).unwrap();
+    } else {
+        // some other request
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-07/404.html b/src/doc/book/listings/ch20-web-server/listing-20-07/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-07/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-07/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-07/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-07/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-07/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-07/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-07/src/main.rs
new file mode 100644
index 000000000..a14b7d538
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-07/src/main.rs
@@ -0,0 +1,45 @@
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    if request_line == "GET / HTTP/1.1" {
+        let status_line = "HTTP/1.1 200 OK";
+        let contents = fs::read_to_string("hello.html").unwrap();
+        let length = contents.len();
+
+        let response = format!(
+            "{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}"
+        );
+
+        stream.write_all(response.as_bytes()).unwrap();
+    // ANCHOR: here
+    // --snip--
+    } else {
+        let status_line = "HTTP/1.1 404 NOT FOUND";
+        let contents = fs::read_to_string("404.html").unwrap();
+        let length = contents.len();
+
+        let response = format!(
+            "{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}"
+        );
+
+        stream.write_all(response.as_bytes()).unwrap();
+    }
+    // ANCHOR_END: here
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-09/404.html b/src/doc/book/listings/ch20-web-server/listing-20-09/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-09/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-09/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-09/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-09/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-09/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-09/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-09/src/main.rs
new file mode 100644
index 000000000..ffc51e803
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-09/src/main.rs
@@ -0,0 +1,40 @@
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+// ANCHOR: here
+// --snip--
+
+fn handle_connection(mut stream: TcpStream) {
+    // --snip--
+    // ANCHOR_END: here
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+    // ANCHOR: here
+
+    let (status_line, filename) = if request_line == "GET / HTTP/1.1" {
+        ("HTTP/1.1 200 OK", "hello.html")
+    } else {
+        ("HTTP/1.1 404 NOT FOUND", "404.html")
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-10/404.html b/src/doc/book/listings/ch20-web-server/listing-20-10/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-10/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-10/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-10/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-10/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-10/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-10/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-10/src/main.rs
new file mode 100644
index 000000000..5a18b45c0
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-10/src/main.rs
@@ -0,0 +1,52 @@
+// ANCHOR: here
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+// --snip--
+// ANCHOR_END: here
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        handle_connection(stream);
+    }
+}
+// ANCHOR: here
+
+fn handle_connection(mut stream: TcpStream) {
+    // --snip--
+
+    // ANCHOR_END: here
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    // ANCHOR: here
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    // --snip--
+    // ANCHOR_END: here
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+    // ANCHOR: here
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-11/404.html b/src/doc/book/listings/ch20-web-server/listing-20-11/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-11/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-11/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-11/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-11/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-11/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-11/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-11/src/main.rs
new file mode 100644
index 000000000..1181357b0
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-11/src/main.rs
@@ -0,0 +1,43 @@
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+// ANCHOR: here
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        thread::spawn(|| {
+            handle_connection(stream);
+        });
+    }
+}
+// ANCHOR_END: here
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/404.html b/src/doc/book/listings/ch20-web-server/listing-20-12/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-12/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/output.txt b/src/doc/book/listings/ch20-web-server/listing-20-12/output.txt
new file mode 100644
index 000000000..57a58b960
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/output.txt
@@ -0,0 +1,10 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0433]: failed to resolve: use of undeclared type `ThreadPool`
+  --> src/main.rs:11:16
+   |
+11 |     let pool = ThreadPool::new(4);
+   |                ^^^^^^^^^^ use of undeclared type `ThreadPool`
+
+For more information about this error, try `rustc --explain E0433`.
+error: could not compile `hello` due to previous error
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-12/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-12/src/main.rs
new file mode 100644
index 000000000..21b9a80f1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-12/src/main.rs
@@ -0,0 +1,44 @@
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+// ANCHOR: here
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+// ANCHOR_END: here
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/404.html b/src/doc/book/listings/ch20-web-server/listing-20-13/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-13/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-13/src/lib.rs
new file mode 100644
index 000000000..35960e7c0
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/src/lib.rs
@@ -0,0 +1,27 @@
+pub struct ThreadPool;
+
+// ANCHOR: here
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        ThreadPool
+    }
+
+    // --snip--
+    // ANCHOR_END: here
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-13/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-13/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-13/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/404.html b/src/doc/book/listings/ch20-web-server/listing-20-14/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-14/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-14/src/lib.rs
new file mode 100644
index 000000000..c1fa1828b
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/src/lib.rs
@@ -0,0 +1,40 @@
+// ANCHOR: here
+use std::thread;
+
+pub struct ThreadPool {
+    threads: Vec<thread::JoinHandle<()>>,
+}
+
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let mut threads = Vec::with_capacity(size);
+
+        for _ in 0..size {
+            // create some threads and store them in the vector
+        }
+
+        ThreadPool { threads }
+    }
+    // --snip--
+    // ANCHOR_END: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-14/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-14/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-14/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/404.html b/src/doc/book/listings/ch20-web-server/listing-20-15/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-15/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-15/src/lib.rs
new file mode 100644
index 000000000..80a6eeeb3
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/src/lib.rs
@@ -0,0 +1,53 @@
+// ANCHOR: here
+use std::thread;
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+}
+
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id));
+        }
+
+        ThreadPool { workers }
+    }
+    // --snip--
+    // ANCHOR_END: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+impl Worker {
+    fn new(id: usize) -> Worker {
+        let thread = thread::spawn(|| {});
+
+        Worker { id, thread }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-15/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-15/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-15/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/404.html b/src/doc/book/listings/ch20-web-server/listing-20-16/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-16/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-16/src/lib.rs
new file mode 100644
index 000000000..411c1d003
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/src/lib.rs
@@ -0,0 +1,58 @@
+// ANCHOR: here
+use std::{sync::mpsc, thread};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+struct Job;
+
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id));
+        }
+
+        ThreadPool { workers, sender }
+    }
+    // --snip--
+    // ANCHOR_END: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+impl Worker {
+    fn new(id: usize) -> Worker {
+        let thread = thread::spawn(|| {});
+
+        Worker { id, thread }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-16/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-16/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-16/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/404.html b/src/doc/book/listings/ch20-web-server/listing-20-17/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-17/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/output.txt b/src/doc/book/listings/ch20-web-server/listing-20-17/output.txt
new file mode 100644
index 000000000..8bedfecfd
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/output.txt
@@ -0,0 +1,13 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0382]: use of moved value: `receiver`
+  --> src/lib.rs:26:42
+   |
+21 |         let (sender, receiver) = mpsc::channel();
+   |                      -------- move occurs because `receiver` has type `std::sync::mpsc::Receiver<Job>`, which does not implement the `Copy` trait
+...
+26 |             workers.push(Worker::new(id, receiver));
+   |                                          ^^^^^^^^ value moved here, in previous iteration of loop
+
+For more information about this error, try `rustc --explain E0382`.
+error: could not compile `hello` due to previous error
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-17/src/lib.rs
new file mode 100644
index 000000000..d764879e5
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/src/lib.rs
@@ -0,0 +1,65 @@
+use std::{sync::mpsc, thread};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+struct Job;
+
+// ANCHOR: here
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, receiver));
+        }
+
+        ThreadPool { workers, sender }
+    }
+    // --snip--
+    // ANCHOR_END: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+
+// --snip--
+
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+// ANCHOR: here
+impl Worker {
+    fn new(id: usize, receiver: mpsc::Receiver<Job>) -> Worker {
+        let thread = thread::spawn(|| {
+            receiver;
+        });
+
+        Worker { id, thread }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-17/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-17/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-17/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/404.html b/src/doc/book/listings/ch20-web-server/listing-20-18/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-18/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-18/src/lib.rs
new file mode 100644
index 000000000..4bff8acad
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/src/lib.rs
@@ -0,0 +1,76 @@
+// ANCHOR: here
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+// --snip--
+
+// ANCHOR_END: here
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+struct Job;
+
+// ANCHOR: here
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    // --snip--
+    // ANCHOR_END: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+    // ANCHOR: here
+}
+
+// --snip--
+
+// ANCHOR_END: here
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+// ANCHOR: here
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        // --snip--
+        // ANCHOR_END: here
+        let thread = thread::spawn(|| {
+            receiver;
+        });
+
+        Worker { id, thread }
+        // ANCHOR: here
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-18/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-18/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-18/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/404.html b/src/doc/book/listings/ch20-web-server/listing-20-19/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-19/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-19/src/lib.rs
new file mode 100644
index 000000000..aeb1facd6
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/src/lib.rs
@@ -0,0 +1,69 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+// ANCHOR: here
+// --snip--
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+    // ANCHOR: here
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+// --snip--
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(|| {
+            receiver;
+        });
+
+        Worker { id, thread }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-19/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-19/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-19/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/404.html b/src/doc/book/listings/ch20-web-server/listing-20-20/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-20/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-20/src/lib.rs
new file mode 100644
index 000000000..86157c9e7
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/src/lib.rs
@@ -0,0 +1,68 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+// ANCHOR: here
+// --snip--
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        Worker { id, thread }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-20/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-20/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-20/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/404.html b/src/doc/book/listings/ch20-web-server/listing-20-21/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-21/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-21/src/lib.rs
new file mode 100644
index 000000000..17b37e77b
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/src/lib.rs
@@ -0,0 +1,67 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+// ANCHOR: here
+// --snip--
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || {
+            while let Ok(job) = receiver.lock().unwrap().recv() {
+                println!("Worker {id} got a job; executing.");
+
+                job();
+            }
+        });
+
+        Worker { id, thread }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-21/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-21/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-21/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/404.html b/src/doc/book/listings/ch20-web-server/listing-20-22/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-22/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/output.txt b/src/doc/book/listings/ch20-web-server/listing-20-22/output.txt
new file mode 100644
index 000000000..4402092e9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/output.txt
@@ -0,0 +1,14 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0507]: cannot move out of `worker.thread` which is behind a mutable reference
+    --> src/lib.rs:52:13
+     |
+52   |             worker.thread.join().unwrap();
+     |             ^^^^^^^^^^^^^ ------ `worker.thread` moved due to this method call
+     |             |
+     |             move occurs because `worker.thread` has type `JoinHandle<()>`, which does not implement the `Copy` trait
+     |
+note: this function takes ownership of the receiver `self`, which moves `worker.thread`
+
+For more information about this error, try `rustc --explain E0507`.
+error: could not compile `hello` due to previous error
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-22/src/lib.rs
new file mode 100644
index 000000000..72a8c4808
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/src/lib.rs
@@ -0,0 +1,76 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+// ANCHOR: here
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            worker.thread.join().unwrap();
+        }
+    }
+}
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: thread::JoinHandle<()>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        Worker { id, thread }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-22/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-22/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-22/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/404.html b/src/doc/book/listings/ch20-web-server/listing-20-23/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-23/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-23/src/lib.rs
new file mode 100644
index 000000000..eea339b02
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/src/lib.rs
@@ -0,0 +1,95 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+// ANCHOR: here
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: Option<mpsc::Sender<Job>>,
+}
+// --snip--
+// ANCHOR_END: here
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+// ANCHOR: here
+impl ThreadPool {
+    // ANCHOR_END: here
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    // ANCHOR: here
+    pub fn new(size: usize) -> ThreadPool {
+        // --snip--
+
+        // ANCHOR_END: here
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        // ANCHOR: here
+        ThreadPool {
+            workers,
+            sender: Some(sender),
+        }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.as_ref().unwrap().send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        drop(self.sender.take());
+
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-23/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-23/src/main.rs
new file mode 100644
index 000000000..b6aa046d1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-23/src/main.rs
@@ -0,0 +1,45 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming().take(2) {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/404.html b/src/doc/book/listings/ch20-web-server/listing-20-24/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-24/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-24/src/lib.rs
new file mode 100644
index 000000000..55e8fef8f
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/src/lib.rs
@@ -0,0 +1,92 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: Option<mpsc::Sender<Job>>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool {
+            workers,
+            sender: Some(sender),
+        }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.as_ref().unwrap().send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        drop(self.sender.take());
+
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+// ANCHOR: here
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            match receiver.lock().unwrap().recv() {
+                Ok(job) => {
+                    println!("Worker {id} got a job; executing.");
+
+                    job();
+                }
+                Err(_) => {
+                    println!("Worker {id} disconnected; shutting down.");
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-24/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-24/src/main.rs
new file mode 100644
index 000000000..b6aa046d1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-24/src/main.rs
@@ -0,0 +1,45 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming().take(2) {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/404.html b/src/doc/book/listings/ch20-web-server/listing-20-25/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.lock b/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.toml b/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/hello.html b/src/doc/book/listings/ch20-web-server/listing-20-25/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/src/lib.rs b/src/doc/book/listings/ch20-web-server/listing-20-25/src/lib.rs
new file mode 100644
index 000000000..54c0489ab
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/src/lib.rs
@@ -0,0 +1,92 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: Option<mpsc::Sender<Job>>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool {
+            workers,
+            sender: Some(sender),
+        }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.as_ref().unwrap().send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        drop(self.sender.take());
+
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let message = receiver.lock().unwrap().recv();
+
+            match message {
+                Ok(job) => {
+                    println!("Worker {id} got a job; executing.");
+
+                    job();
+                }
+                Err(_) => {
+                    println!("Worker {id} disconnected; shutting down.");
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/listing-20-25/src/main.rs b/src/doc/book/listings/ch20-web-server/listing-20-25/src/main.rs
new file mode 100644
index 000000000..a649ff103
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/listing-20-25/src/main.rs
@@ -0,0 +1,53 @@
+use hello::ThreadPool;
+use std::fs;
+use std::io::prelude::*;
+use std::net::TcpListener;
+use std::net::TcpStream;
+use std::thread;
+use std::time::Duration;
+
+// ANCHOR: here
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming().take(2) {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+// ANCHOR_END: here
+
+fn handle_connection(mut stream: TcpStream) {
+    let mut buffer = [0; 1024];
+    stream.read(&mut buffer).unwrap();
+
+    let get = b"GET / HTTP/1.1\r\n";
+    let sleep = b"GET /sleep HTTP/1.1\r\n";
+
+    let (status_line, filename) = if buffer.starts_with(get) {
+        ("HTTP/1.1 200 OK", "hello.html")
+    } else if buffer.starts_with(sleep) {
+        thread::sleep(Duration::from_secs(5));
+        ("HTTP/1.1 200 OK", "hello.html")
+    } else {
+        ("HTTP/1.1 404 NOT FOUND", "404.html")
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+
+    let response = format!(
+        "{}\r\nContent-Length: {}\r\n\r\n{}",
+        status_line,
+        contents.len(),
+        contents
+    );
+
+    stream.write_all(response.as_bytes()).unwrap();
+    stream.flush().unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/404.html b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt
new file mode 100644
index 000000000..fa337b8a8
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/output.txt
@@ -0,0 +1,10 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0599]: no function or associated item named `new` found for struct `ThreadPool` in the current scope
+  --> src/main.rs:12:28
+   |
+12 |     let pool = ThreadPool::new(4);
+   |                            ^^^ function or associated item not found in `ThreadPool`
+
+For more information about this error, try `rustc --explain E0599`.
+error: could not compile `hello` due to previous error
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/lib.rs
new file mode 100644
index 000000000..7312e293d
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/lib.rs
@@ -0,0 +1 @@
+pub struct ThreadPool;
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/main.rs
new file mode 100644
index 000000000..f7b42167f
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-01-define-threadpool-struct/src/main.rs
@@ -0,0 +1,45 @@
+// ANCHOR: here
+use hello::ThreadPool;
+// ANCHOR_END: here
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/404.html b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt
new file mode 100644
index 000000000..44c8f3953
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/output.txt
@@ -0,0 +1,10 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0599]: no method named `execute` found for struct `ThreadPool` in the current scope
+  --> src/main.rs:17:14
+   |
+17 |         pool.execute(|| {
+   |              ^^^^^^^ method not found in `ThreadPool`
+
+For more information about this error, try `rustc --explain E0599`.
+error: could not compile `hello` due to previous error
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/lib.rs
new file mode 100644
index 000000000..f0e1890bb
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/lib.rs
@@ -0,0 +1,7 @@
+pub struct ThreadPool;
+
+impl ThreadPool {
+    pub fn new(size: usize) -> ThreadPool {
+        ThreadPool
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-02-impl-threadpool-new/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/404.html b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/output.txt b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/output.txt
new file mode 100644
index 000000000..dc76c43d6
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/output.txt
@@ -0,0 +1,3 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+    Finished dev [unoptimized + debuginfo] target(s) in 0.24s
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/lib.rs
new file mode 100644
index 000000000..1321ab873
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/lib.rs
@@ -0,0 +1,18 @@
+pub struct ThreadPool;
+
+// ANCHOR: here
+impl ThreadPool {
+    // --snip--
+    // ANCHOR_END: here
+    pub fn new(size: usize) -> ThreadPool {
+        ThreadPool
+    }
+
+    // ANCHOR: here
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-03-define-execute/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/404.html b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/output.txt b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/output.txt
new file mode 100644
index 000000000..34d30fe05
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/output.txt
@@ -0,0 +1,24 @@
+$ cargo check
+    Checking hello v0.1.0 (file:///projects/hello)
+error[E0599]: no method named `join` found for enum `Option` in the current scope
+  --> src/lib.rs:52:27
+   |
+52 |             worker.thread.join().unwrap();
+   |                           ^^^^ method not found in `Option<JoinHandle<()>>`
+
+error[E0308]: mismatched types
+  --> src/lib.rs:72:22
+   |
+72 |         Worker { id, thread }
+   |                      ^^^^^^ expected enum `Option`, found struct `JoinHandle`
+   |
+   = note: expected enum `Option<JoinHandle<()>>`
+            found struct `JoinHandle<_>`
+help: try wrapping the expression in `Some`
+   |
+72 |         Worker { id, thread: Some(thread) }
+   |                      +++++++++++++      +
+
+Some errors have detailed explanations: E0308, E0599.
+For more information about an error, try `rustc --explain E0308`.
+error: could not compile `hello` due to 2 previous errors
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/lib.rs
new file mode 100644
index 000000000..6ef710a26
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/lib.rs
@@ -0,0 +1,76 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            worker.thread.join().unwrap();
+        }
+    }
+}
+
+// ANCHOR: here
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+// ANCHOR_END: here
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        Worker { id, thread }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-04-update-worker-definition/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/404.html b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/lib.rs
new file mode 100644
index 000000000..ede3750a1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/lib.rs
@@ -0,0 +1,83 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            worker.thread.join().unwrap();
+        }
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+// ANCHOR: here
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        // --snip--
+
+        // ANCHOR_END: here
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        // ANCHOR: here
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
+// ANCHOR_END: here
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/main.rs
new file mode 100644
index 000000000..79efb28a2
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-05-fix-worker-new/src/main.rs
@@ -0,0 +1,43 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming() {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/404.html b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/lib.rs
new file mode 100644
index 000000000..b795ea53b
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/lib.rs
@@ -0,0 +1,81 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.send(job).unwrap();
+    }
+}
+
+// ANCHOR: here
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+// ANCHOR_END: here
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv().unwrap();
+
+            println!("Worker {id} got a job; executing.");
+
+            job();
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/main.rs
new file mode 100644
index 000000000..b6aa046d1
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-06-fix-threadpool-drop/src/main.rs
@@ -0,0 +1,45 @@
+use hello::ThreadPool;
+use std::{
+    fs,
+    io::{prelude::*, BufReader},
+    net::{TcpListener, TcpStream},
+    thread,
+    time::Duration,
+};
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming().take(2) {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let buf_reader = BufReader::new(&mut stream);
+    let request_line = buf_reader.lines().next().unwrap().unwrap();
+
+    let (status_line, filename) = match &request_line[..] {
+        "GET / HTTP/1.1" => ("HTTP/1.1 200 OK", "hello.html"),
+        "GET /sleep HTTP/1.1" => {
+            thread::sleep(Duration::from_secs(5));
+            ("HTTP/1.1 200 OK", "hello.html")
+        }
+        _ => ("HTTP/1.1 404 NOT FOUND", "404.html"),
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+    let length = contents.len();
+
+    let response =
+        format!("{status_line}\r\nContent-Length: {length}\r\n\r\n{contents}");
+
+    stream.write_all(response.as_bytes()).unwrap();
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/404.html b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/404.html
new file mode 100644
index 000000000..88d8e9152
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/404.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Oops!</h1>
+    <p>Sorry, I don't know what you're asking for.</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.lock b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.lock
new file mode 100644
index 000000000..f2d069f46
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.lock
@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello"
+version = "0.1.0"
+
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.toml b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.toml
new file mode 100644
index 000000000..fe619478a
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "hello"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/hello.html b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/hello.html
new file mode 100644
index 000000000..fe442d6b9
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/hello.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8">
+    <title>Hello!</title>
+  </head>
+  <body>
+    <h1>Hello!</h1>
+    <p>Hi from Rust</p>
+  </body>
+</html>
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/lib.rs b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/lib.rs
new file mode 100644
index 000000000..54c0489ab
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/lib.rs
@@ -0,0 +1,92 @@
+use std::{
+    sync::{mpsc, Arc, Mutex},
+    thread,
+};
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: Option<mpsc::Sender<Job>>,
+}
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+impl ThreadPool {
+    /// Create a new ThreadPool.
+    ///
+    /// The size is the number of threads in the pool.
+    ///
+    /// # Panics
+    ///
+    /// The `new` function will panic if the size is zero.
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+
+        let receiver = Arc::new(Mutex::new(receiver));
+
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool {
+            workers,
+            sender: Some(sender),
+        }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+
+        self.sender.as_ref().unwrap().send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        drop(self.sender.take());
+
+        for worker in &mut self.workers {
+            println!("Shutting down worker {}", worker.id);
+
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+
+struct Worker {
+    id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let message = receiver.lock().unwrap().recv();
+
+            match message {
+                Ok(job) => {
+                    println!("Worker {id} got a job; executing.");
+
+                    job();
+                }
+                Err(_) => {
+                    println!("Worker {id} disconnected; shutting down.");
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            id,
+            thread: Some(thread),
+        }
+    }
+}
diff --git a/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/main.rs b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/main.rs
new file mode 100644
index 000000000..3161c2ee5
--- /dev/null
+++ b/src/doc/book/listings/ch20-web-server/no-listing-07-final-code/src/main.rs
@@ -0,0 +1,51 @@
+use hello::ThreadPool;
+use std::fs;
+use std::io::prelude::*;
+use std::net::TcpListener;
+use std::net::TcpStream;
+use std::thread;
+use std::time::Duration;
+
+fn main() {
+    let listener = TcpListener::bind("127.0.0.1:7878").unwrap();
+    let pool = ThreadPool::new(4);
+
+    for stream in listener.incoming().take(2) {
+        let stream = stream.unwrap();
+
+        pool.execute(|| {
+            handle_connection(stream);
+        });
+    }
+
+    println!("Shutting down.");
+}
+
+fn handle_connection(mut stream: TcpStream) {
+    let mut buffer = [0; 1024];
+    stream.read(&mut buffer).unwrap();
+
+    let get = b"GET / HTTP/1.1\r\n";
+    let sleep = b"GET /sleep HTTP/1.1\r\n";
+
+    let (status_line, filename) = if buffer.starts_with(get) {
+        ("HTTP/1.1 200 OK", "hello.html")
+    } else if buffer.starts_with(sleep) {
+        thread::sleep(Duration::from_secs(5));
+        ("HTTP/1.1 200 OK", "hello.html")
+    } else {
+        ("HTTP/1.1 404 NOT FOUND", "404.html")
+    };
+
+    let contents = fs::read_to_string(filename).unwrap();
+
+    let response = format!(
+        "{}\r\nContent-Length: {}\r\n\r\n{}",
+        status_line,
+        contents.len(),
+        contents
+    );
+
+    stream.write_all(response.as_bytes()).unwrap();
+    stream.flush().unwrap();
+}
-- 
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