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[report]
include =
*glances*
omit =
setup.py
glances/outputs/*
glances/exports/*
glances/compat.py
glances/autodiscover.py
glances/client_browser.py
glances/config.py
glances/history.py
glances/monitored_list.py//! 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.
#![warn(rust_2018_idioms)]
use bytes::BytesMut;
use futures::{SinkExt, StreamExt};
use http::{header::HeaderValue, Request, Response, StatusCode};
use serde::Serialize;
use std::{env, error::Error, fmt, io};
use tokio::{
codec::{Decoder, Encoder, Framed},
net::{TcpListener, TcpStream},
};
#[tokio::main]
async fn main() -> Result<(), Box<dyn 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 mut incoming = TcpListener::bind(&addr).await?.incoming();
println!("Listening on: {}", addr);
while let Some(Ok(stream)) = incoming.next().await {
tokio::spawn(async move {
if let Err(e) = process(stream).await {
println!("failed to process connection; error = {}", e);
}
});
}
Ok(())
}
async fn process(stream: TcpStream) -> Result<(), Box<dyn Error>> {
let mut transport = Framed::new(stream, Http);
while let Some(request) = transport.next().await {
match request {
Ok(request) => {
let response = respond(request).await?;
transport.send(response).await?;
}
Err(e) => return Err(e.into()),
}
}
Ok(())
}
async fn respond(req: Request<()>) -> Result<Response<String>, Box<dyn Error>> {
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)
}
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 fmt::Write for BytesWrite<'_> {
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
|