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use anyhow::bail;
use futures_lite::prelude::*;
use http::header::HeaderName;
use http::{HeaderValue, Method, Request, Uri, Version};
use std::pin::Pin;
use std::task::{Context, Poll};
#[derive(Copy, Clone, Debug)]
pub struct RequestHeadDecoder {
max_head_size: usize,
max_headers: usize,
}
impl RequestHeadDecoder {
pub fn decode<T: AsyncRead + Unpin>(self, transport: T) -> RequestHeadDecode<T> {
RequestHeadDecode {
buffer: Vec::with_capacity(self.max_head_size),
transport: Some(transport),
decoder: self,
completion: 0,
}
}
}
impl Default for RequestHeadDecoder {
fn default() -> Self {
Self {
max_head_size: 8192,
max_headers: 128,
}
}
}
pub struct RequestHeadDecode<T: AsyncRead + Unpin> {
buffer: Vec<u8>,
transport: Option<T>,
decoder: RequestHeadDecoder,
completion: usize,
}
impl<T: AsyncRead + Unpin> Future for RequestHeadDecode<T> {
type Output = anyhow::Result<(T, Request<()>)>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let mut transport = self.transport.take().unwrap();
const END: &[u8; 4] = b"\r\n\r\n";
let mut chunk = [0u8; END.len()];
loop {
let chunk = &mut chunk[self.completion..4];
if self.buffer.len() + chunk.len() > self.buffer.capacity() {
return Poll::Ready(Err(anyhow::Error::msg("request head too long")));
}
match Pin::new(&mut transport).poll_read(cx, chunk) {
Poll::Ready(Ok(n)) => {
let mut chunk = &chunk[0..n];
self.buffer.extend_from_slice(chunk);
while self.completion == 0 && chunk.len() > 0 {
if chunk[0] == END[0] {
self.completion = 1
}
chunk = &chunk[1..];
}
match chunk == &END[self.completion..self.completion + chunk.len()] {
true => self.completion += chunk.len(),
false => self.completion = 0,
}
if self.completion == END.len() {
return Poll::Ready(
request_head_parse(&self.buffer, self.decoder.max_headers)
.map(|request| (transport, request)),
);
}
}
Poll::Ready(Err(err)) => return Poll::Ready(Err(err.into())),
Poll::Pending => {
self.transport = Some(transport);
return Poll::Pending;
}
}
}
}
}
fn request_head_parse(buffer: &[u8], max_headers: usize) -> anyhow::Result<Request<()>> {
let mut headers = vec![httparse::EMPTY_HEADER; max_headers];
let mut parsed_request = httparse::Request::new(&mut headers);
if parsed_request.parse(buffer)?.is_partial() {
bail!("invalid HTTP head")
}
if parsed_request.version != Some(1) {
bail!("unsupported HTTP version")
}
let method = Method::from_bytes(parsed_request.method.unwrap_or("").as_bytes())?;
let uri = parsed_request.path.unwrap_or("").parse::<Uri>()?;
let mut request = Request::builder()
.method(method)
.uri(uri)
.version(Version::HTTP_11)
.body(())?;
let headers = request.headers_mut();
headers.reserve(parsed_request.headers.len());
for header in parsed_request.headers {
headers.append(
HeaderName::from_bytes(header.name.as_bytes())?,
HeaderValue::from_bytes(header.value)?,
);
}
Ok(request)
}
#[cfg(test)]
mod tests {
use crate::head::decode::RequestHeadDecoder;
use futures_lite::future::block_on;
use futures_lite::io::Cursor;
use futures_lite::{AsyncReadExt, StreamExt};
use http::{Method, Request, Version};
const INPUT: &[u8] = b"GET / HTTP/1.1\r\nHost: www.example.com\r\nConnection: close\r\n\r\n ";
async fn check(output: Request<()>, transport: Cursor<&[u8]>) {
assert_eq!(output.version(), Version::HTTP_11);
assert_eq!(output.method(), Method::GET);
assert_eq!(
output.headers().get("Host").unwrap().as_bytes(),
b"www.example.com"
);
assert_eq!(
output.headers().get("Connection").unwrap().as_bytes(),
b"close"
);
assert_eq!(transport.bytes().count().await, 1);
}
#[test]
fn owned_transport() {
block_on(async {
let transport = Cursor::new(INPUT);
let (transport, output) = RequestHeadDecoder::default()
.decode(transport)
.await
.unwrap();
check(output, transport).await;
})
}
#[test]
fn referenced_transport() {
block_on(async {
let mut transport = Cursor::new(INPUT);
let (_, output) = RequestHeadDecoder::default()
.decode(&mut transport)
.await
.unwrap();
check(output, transport).await;
})
}
}