diff options
Diffstat (limited to 'third_party/rust/tokio-0.1.22/examples/tinyhttp.rs')
| -rw-r--r-- | third_party/rust/tokio-0.1.22/examples/tinyhttp.rs | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/third_party/rust/tokio-0.1.22/examples/tinyhttp.rs b/third_party/rust/tokio-0.1.22/examples/tinyhttp.rs new file mode 100644 index 0000000000..cde1b79afb --- /dev/null +++ b/third_party/rust/tokio-0.1.22/examples/tinyhttp.rs @@ -0,0 +1,325 @@ +//! A "tiny" example of HTTP request/response handling using transports. +//! +//! This example is intended for *learning purposes* to see how various pieces +//! hook up together and how HTTP can get up and running. Note that this example +//! is written with the restriction that it *can't* use any "big" library other +//! than Tokio, if you'd like a "real world" HTTP library you likely want a +//! crate like Hyper. +//! +//! Code here is based on the `echo-threads` example and implements two paths, +//! the `/plaintext` and `/json` routes to respond with some text and json, +//! respectively. By default this will run I/O on all the cores your system has +//! available, and it doesn't support HTTP request bodies. + +#![deny(warnings)] + +extern crate bytes; +extern crate http; +extern crate httparse; +#[macro_use] +extern crate serde_derive; +extern crate serde_json; +extern crate time; +extern crate tokio; +extern crate tokio_io; + +use std::net::SocketAddr; +use std::{env, fmt, io}; + +use tokio::codec::{Decoder, Encoder}; +use tokio::net::{TcpListener, TcpStream}; +use tokio::prelude::*; + +use bytes::BytesMut; +use http::header::HeaderValue; +use http::{Request, Response, StatusCode}; + +fn main() -> Result<(), Box<std::error::Error>> { + // Parse the arguments, bind the TCP socket we'll be listening to, spin up + // our worker threads, and start shipping sockets to those worker threads. + let addr = env::args().nth(1).unwrap_or("127.0.0.1:8080".to_string()); + let addr = addr.parse::<SocketAddr>()?; + + let listener = TcpListener::bind(&addr)?; + println!("Listening on: {}", addr); + + tokio::run({ + listener + .incoming() + .map_err(|e| println!("failed to accept socket; error = {:?}", e)) + .for_each(|socket| { + process(socket); + Ok(()) + }) + }); + Ok(()) +} + +fn process(socket: TcpStream) { + let (tx, rx) = + // Frame the socket using the `Http` protocol. This maps the TCP socket + // to a Stream + Sink of HTTP frames. + Http.framed(socket) + // This splits a single `Stream + Sink` value into two separate handles + // that can be used independently (even on different tasks or threads). + .split(); + + // Map all requests into responses and send them back to the client. + let task = tx.send_all(rx.and_then(respond)).then(|res| { + if let Err(e) = res { + println!("failed to process connection; error = {:?}", e); + } + + Ok(()) + }); + + // Spawn the task that handles the connection. + tokio::spawn(task); +} + +/// "Server logic" is implemented in this function. +/// +/// This function is a map from and HTTP request to a future of a response and +/// represents the various handling a server might do. Currently the contents +/// here are pretty uninteresting. +fn respond(req: Request<()>) -> Box<Future<Item = Response<String>, Error = io::Error> + Send> { + let f = future::lazy(move || { + let mut response = Response::builder(); + let body = match req.uri().path() { + "/plaintext" => { + response.header("Content-Type", "text/plain"); + "Hello, World!".to_string() + } + "/json" => { + response.header("Content-Type", "application/json"); + + #[derive(Serialize)] + struct Message { + message: &'static str, + } + serde_json::to_string(&Message { + message: "Hello, World!", + })? + } + _ => { + response.status(StatusCode::NOT_FOUND); + String::new() + } + }; + let response = response + .body(body) + .map_err(|err| io::Error::new(io::ErrorKind::Other, err))?; + Ok(response) + }); + + Box::new(f) +} + +struct Http; + +/// Implementation of encoding an HTTP response into a `BytesMut`, basically +/// just writing out an HTTP/1.1 response. +impl Encoder for Http { + type Item = Response<String>; + type Error = io::Error; + + fn encode(&mut self, item: Response<String>, dst: &mut BytesMut) -> io::Result<()> { + use std::fmt::Write; + + write!( + BytesWrite(dst), + "\ + HTTP/1.1 {}\r\n\ + Server: Example\r\n\ + Content-Length: {}\r\n\ + Date: {}\r\n\ + ", + item.status(), + item.body().len(), + date::now() + ) + .unwrap(); + + for (k, v) in item.headers() { + dst.extend_from_slice(k.as_str().as_bytes()); + dst.extend_from_slice(b": "); + dst.extend_from_slice(v.as_bytes()); + dst.extend_from_slice(b"\r\n"); + } + + dst.extend_from_slice(b"\r\n"); + dst.extend_from_slice(item.body().as_bytes()); + + return Ok(()); + + // Right now `write!` on `Vec<u8>` goes through io::Write and is not + // super speedy, so inline a less-crufty implementation here which + // doesn't go through io::Error. + struct BytesWrite<'a>(&'a mut BytesMut); + + impl<'a> fmt::Write for BytesWrite<'a> { + fn write_str(&mut self, s: &str) -> fmt::Result { + self.0.extend_from_slice(s.as_bytes()); + Ok(()) + } + + fn write_fmt(&mut self, args: fmt::Arguments) -> fmt::Result { + fmt::write(self, args) + } + } + } +} + +/// Implementation of decoding an HTTP request from the bytes we've read so far. +/// This leverages the `httparse` crate to do the actual parsing and then we use +/// that information to construct an instance of a `http::Request` object, +/// trying to avoid allocations where possible. +impl Decoder for Http { + type Item = Request<()>; + type Error = io::Error; + + fn decode(&mut self, src: &mut BytesMut) -> io::Result<Option<Request<()>>> { + // TODO: we should grow this headers array if parsing fails and asks + // for more headers + let mut headers = [None; 16]; + let (method, path, version, amt) = { + let mut parsed_headers = [httparse::EMPTY_HEADER; 16]; + let mut r = httparse::Request::new(&mut parsed_headers); + let status = r.parse(src).map_err(|e| { + let msg = format!("failed to parse http request: {:?}", e); + io::Error::new(io::ErrorKind::Other, msg) + })?; + + let amt = match status { + httparse::Status::Complete(amt) => amt, + httparse::Status::Partial => return Ok(None), + }; + + let toslice = |a: &[u8]| { + let start = a.as_ptr() as usize - src.as_ptr() as usize; + assert!(start < src.len()); + (start, start + a.len()) + }; + + for (i, header) in r.headers.iter().enumerate() { + let k = toslice(header.name.as_bytes()); + let v = toslice(header.value); + headers[i] = Some((k, v)); + } + + ( + toslice(r.method.unwrap().as_bytes()), + toslice(r.path.unwrap().as_bytes()), + r.version.unwrap(), + amt, + ) + }; + if version != 1 { + return Err(io::Error::new( + io::ErrorKind::Other, + "only HTTP/1.1 accepted", + )); + } + let data = src.split_to(amt).freeze(); + let mut ret = Request::builder(); + ret.method(&data[method.0..method.1]); + ret.uri(data.slice(path.0, path.1)); + ret.version(http::Version::HTTP_11); + for header in headers.iter() { + let (k, v) = match *header { + Some((ref k, ref v)) => (k, v), + None => break, + }; + let value = unsafe { HeaderValue::from_shared_unchecked(data.slice(v.0, v.1)) }; + ret.header(&data[k.0..k.1], value); + } + + let req = ret + .body(()) + .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?; + Ok(Some(req)) + } +} + +mod date { + use std::cell::RefCell; + use std::fmt::{self, Write}; + use std::str; + + use time::{self, Duration}; + + pub struct Now(()); + + /// Returns a struct, which when formatted, renders an appropriate `Date` + /// header value. + pub fn now() -> Now { + Now(()) + } + + // Gee Alex, doesn't this seem like premature optimization. Well you see + // there Billy, you're absolutely correct! If your server is *bottlenecked* + // on rendering the `Date` header, well then boy do I have news for you, you + // don't need this optimization. + // + // In all seriousness, though, a simple "hello world" benchmark which just + // sends back literally "hello world" with standard headers actually is + // bottlenecked on rendering a date into a byte buffer. Since it was at the + // top of a profile, and this was done for some competitive benchmarks, this + // module was written. + // + // Just to be clear, though, I was not intending on doing this because it + // really does seem kinda absurd, but it was done by someone else [1], so I + // blame them! :) + // + // [1]: https://github.com/rapidoid/rapidoid/blob/f1c55c0555007e986b5d069fe1086e6d09933f7b/rapidoid-commons/src/main/java/org/rapidoid/commons/Dates.java#L48-L66 + + struct LastRenderedNow { + bytes: [u8; 128], + amt: usize, + next_update: time::Timespec, + } + + thread_local!(static LAST: RefCell<LastRenderedNow> = RefCell::new(LastRenderedNow { + bytes: [0; 128], + amt: 0, + next_update: time::Timespec::new(0, 0), + })); + + impl fmt::Display for Now { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + LAST.with(|cache| { + let mut cache = cache.borrow_mut(); + let now = time::get_time(); + if now >= cache.next_update { + cache.update(now); + } + f.write_str(cache.buffer()) + }) + } + } + + impl LastRenderedNow { + fn buffer(&self) -> &str { + str::from_utf8(&self.bytes[..self.amt]).unwrap() + } + + fn update(&mut self, now: time::Timespec) { + self.amt = 0; + write!(LocalBuffer(self), "{}", time::at(now).rfc822()).unwrap(); + self.next_update = now + Duration::seconds(1); + self.next_update.nsec = 0; + } + } + + struct LocalBuffer<'a>(&'a mut LastRenderedNow); + + impl<'a> fmt::Write for LocalBuffer<'a> { + fn write_str(&mut self, s: &str) -> fmt::Result { + let start = self.0.amt; + let end = start + s.len(); + self.0.bytes[start..end].copy_from_slice(s.as_bytes()); + self.0.amt += s.len(); + Ok(()) + } + } +} |