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Diffstat (limited to 'third_party/rust/tokio-0.1.22/examples/print_each_packet.rs')
| -rw-r--r-- | third_party/rust/tokio-0.1.22/examples/print_each_packet.rs | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/third_party/rust/tokio-0.1.22/examples/print_each_packet.rs b/third_party/rust/tokio-0.1.22/examples/print_each_packet.rs new file mode 100644 index 0000000000..94a606483c --- /dev/null +++ b/third_party/rust/tokio-0.1.22/examples/print_each_packet.rs @@ -0,0 +1,150 @@ +//! A "print-each-packet" server with Tokio +//! +//! This server will create a TCP listener, accept connections in a loop, and +//! put down in the stdout everything that's read off of each TCP connection. +//! +//! Because the Tokio runtime uses a thread pool, each TCP connection is +//! processed concurrently with all other TCP connections across multiple +//! threads. +//! +//! To see this server in action, you can run this in one terminal: +//! +//! cargo run --example print\_each\_packet +//! +//! and in another terminal you can run: +//! +//! cargo run --example connect 127.0.0.1:8080 +//! +//! Each line you type in to the `connect` terminal should be written to terminal! +//! +//! Minimal js example: +//! +//! ```js +//! var net = require("net"); +//! +//! var listenPort = 8080; +//! +//! var server = net.createServer(function (socket) { +//! socket.on("data", function (bytes) { +//! console.log("bytes", bytes); +//! }); +//! +//! socket.on("end", function() { +//! console.log("Socket received FIN packet and closed connection"); +//! }); +//! socket.on("error", function (error) { +//! console.log("Socket closed with error", error); +//! }); +//! +//! socket.on("close", function (with_error) { +//! if (with_error) { +//! console.log("Socket closed with result: Err(SomeError)"); +//! } else { +//! console.log("Socket closed with result: Ok(())"); +//! } +//! }); +//! +//! }); +//! +//! server.listen(listenPort); +//! +//! console.log("Listening on:", listenPort); +//! ``` +//! + +#![deny(warnings)] + +extern crate tokio; +extern crate tokio_codec; + +use tokio::codec::Decoder; +use tokio::net::TcpListener; +use tokio::prelude::*; +use tokio_codec::BytesCodec; + +use std::env; +use std::net::SocketAddr; + +fn main() -> Result<(), Box<std::error::Error>> { + // Allow passing an address to listen on as the first argument of this + // program, but otherwise we'll just set up our TCP listener on + // 127.0.0.1:8080 for connections. + let addr = env::args().nth(1).unwrap_or("127.0.0.1:8080".to_string()); + let addr = addr.parse::<SocketAddr>()?; + + // Next up we create a TCP listener which will listen for incoming + // connections. This TCP listener is bound to the address we determined + // above and must be associated with an event loop, so we pass in a handle + // to our event loop. After the socket's created we inform that we're ready + // to go and start accepting connections. + let socket = TcpListener::bind(&addr)?; + println!("Listening on: {}", addr); + + // Here we convert the `TcpListener` to a stream of incoming connections + // with the `incoming` method. We then define how to process each element in + // the stream with the `for_each` method. + // + // This combinator, defined on the `Stream` trait, will allow us to define a + // computation to happen for all items on the stream (in this case TCP + // connections made to the server). The return value of the `for_each` + // method is itself a future representing processing the entire stream of + // connections, and ends up being our server. + let done = socket + .incoming() + .map_err(|e| println!("failed to accept socket; error = {:?}", e)) + .for_each(move |socket| { + // Once we're inside this closure this represents an accepted client + // from our server. The `socket` is the client connection (similar to + // how the standard library operates). + // + // We're parsing each socket with the `BytesCodec` included in `tokio_io`, + // and then we `split` each codec into the reader/writer halves. + // + // See https://docs.rs/tokio-codec/0.1/src/tokio_codec/bytes_codec.rs.html + let framed = BytesCodec::new().framed(socket); + let (_writer, reader) = framed.split(); + + let processor = reader + .for_each(|bytes| { + println!("bytes: {:?}", bytes); + Ok(()) + }) + // After our copy operation is complete we just print out some helpful + // information. + .and_then(|()| { + println!("Socket received FIN packet and closed connection"); + Ok(()) + }) + .or_else(|err| { + println!("Socket closed with error: {:?}", err); + // We have to return the error to catch it in the next ``.then` call + Err(err) + }) + .then(|result| { + println!("Socket closed with result: {:?}", result); + Ok(()) + }); + + // And this is where much of the magic of this server happens. We + // crucially want all clients to make progress concurrently, rather than + // blocking one on completion of another. To achieve this we use the + // `tokio::spawn` function to execute the work in the background. + // + // This function will transfer ownership of the future (`msg` in this + // case) to the Tokio runtime thread pool that. The thread pool will + // drive the future to completion. + // + // Essentially here we're executing a new task to run concurrently, + // which will allow all of our clients to be processed concurrently. + tokio::spawn(processor) + }); + + // And finally now that we've define what our server is, we run it! + // + // This starts the Tokio runtime, spawns the server task, and blocks the + // current thread until all tasks complete execution. Since the `done` task + // never completes (it just keeps accepting sockets), `tokio::run` blocks + // forever (until ctrl-c is pressed). + tokio::run(done); + Ok(()) +} |