Added complex timeout override option to builder

This commit is contained in:
Emi Tatsuo 2020-11-19 01:25:34 -05:00
parent a778774189
commit 94d7a5ab4f
Signed by: Emi
GPG key ID: 68FAB2E2E6DFC98B

View file

@ -40,6 +40,7 @@ pub struct Server {
listener: Arc<TcpListener>,
handler: Handler,
timeout: Duration,
complex_timeout: Option<Duration>,
}
impl Server {
@ -101,31 +102,116 @@ impl Server {
})
.context("Request handler failed")?;
// Use a timeout for sending the response
let fut_send_and_flush = async {
send_response(response, &mut stream).await
self.send_response(response, &mut stream).await
.context("Failed to send response")?;
Ok(())
}
async fn send_response(&self, mut response: Response, stream: &mut (impl AsyncWrite + Unpin)) -> Result<()> {
let maybe_body = response.take_body();
let header = response.header();
// Okay, I know this method looks really complicated, but I promise it's not.
// There's really only three things this method does:
//
// * Send the response header
// * Send the response body
// * Flush the stream
//
// All the other code is doing one of two things. Either it's
//
// * code to add and handle timeouts (that's what all the async blocks and calls
// to tokio::time::timeout are), or
// * logic to decide whether to use the special case timeout handling (seperate
// timeouts for the header and the body) vs the normal timeout handling (header,
// body, and flush all as one timeout)
//
// The split between the two cases happens at this very first if block.
// Everything in this deep chain of if's and if-let's is for the special case. If
// any one of the ifs fails, the code after the big if block is run, and that's
// the normal case.
//
// Hope this helps! Emi <3
if header.status == Status::SUCCESS && maybe_body.is_some() {
// aaaa let me have if-let chaining ;_;
if let "text/plain"|"text/gemini" = header.meta.as_str() {
if let Some(cplx_timeout) = self.complex_timeout {
////////////// Use the special case timeout override /////////////////////////////
// Send the header & flush
let fut_send_header = async {
send_response_header(response.header(), stream).await
.context("Failed to write response header")?;
stream.flush()
.await
.context("Failed to flush response header")
};
tokio::time::timeout(self.timeout, fut_send_header)
.await
.context("Timed out while sending response header")??;
// Send the body & flush
let fut_send_body = async {
send_response_body(maybe_body.unwrap(), stream).await
.context("Failed to write response body")?;
stream.flush()
.await
.context("Failed to flush response body")
};
tokio::time::timeout(cplx_timeout, fut_send_body)
.await
.context("Timed out while sending response body")??;
return Ok(())
}
}
}
///////////// Use the normal timeout /////////////////////////////////////////////
let fut_send_response = async {
send_response_header(response.header(), stream).await
.context("Failed to write response header")?;
if let Some(body) = maybe_body {
send_response_body(body, stream).await
.context("Failed to write response body")?;
}
stream.flush()
.await
.context("Failed to flush response data")
};
timeout(self.timeout, fut_send_and_flush)
tokio::time::timeout(self.timeout, fut_send_response)
.await
.context("Client timed out receiving response data")??;
.context("Timed out while sending response data")??;
Ok(())
//////////////////////////////////////////////////////////////////////////////////
}
}
pub struct Builder<A> {
addr: A,
timeout: Duration,
complex_body_timeout_override: Option<Duration>,
}
impl<A: ToSocketAddrs> Builder<A> {
fn bind(addr: A) -> Self {
Self { addr, timeout: Duration::from_secs(30) }
Self {
addr,
timeout: Duration::from_secs(1),
complex_body_timeout_override: Some(Duration::from_secs(30)),
}
}
/// Set the timeout on incoming requests
@ -139,17 +225,54 @@ impl<A: ToSocketAddrs> Builder<A> {
/// If you would like a timeout for your code itself, please use
/// [`tokio::time::Timeout`] to implement it internally.
///
/// **The default timeout is 30 seconds.** If you are considering changing this, keep
/// in mind that some clients, when recieving a file type not supported for display,
/// will prompt the user how they would like to proceed. While this occurs, the
/// request hangs open. Setting a short timeout may close the prompt before user has
/// a chance to respond. If you are only serving `text/plain` and `text/gemini`, this
/// should not be a problem.
/// **The default timeout is 1 second.** As somewhat of a workaround for
/// shortcomings of the specification, this timeout, and any timeout set using this
/// method, is overridden in special cases, specifically for MIME types outside of
/// `text/plain` and `text/gemini`, to be 30 seconds. If you would like to change or
/// prevent this, please see
/// [`override_complex_body_timeout`](Self::override_complex_body_timeout()).
pub fn set_timeout(mut self, timeout: Duration) -> Self {
self.timeout = timeout;
self
}
/// Override the timeout for complex body types
///
/// Many clients choose to handle body types which cannot be displayed by prompting
/// the user if they would like to download or open the request body. However, since
/// this prompt occurs in the middle of receiving a request, often the connection
/// times out before the end user is able to respond to the prompt.
///
/// As a workaround, it is possible to set an override on the request timeout in
/// specific conditions:
///
/// 1. **Only override the timeout for receiving the body of the request.** This will
/// not override the timeout on sending the request header, nor on receiving the
/// response header.
/// 2. **Only override the timeout for successful responses.** The only bodies which
/// have bodies are successful ones. In all other cases, there's no body to
/// timeout for
/// 3. **Only override the timeout for complex body types.** Almost all clients are
/// able to display `text/plain` and `text/gemini` responses, and will not prompt
/// the user for these response types. This means that there is no reason to
/// expect a client to have a human-length response time for these MIME types.
/// Because of this, responses of this type will not be overridden.
///
/// This method is used to override the timeout for responses meeting these specific
/// criteria. All other stages of the connection will use the timeout specified in
/// [`set_timeout()`](Self::set_timeout()).
///
/// If this is set to [`None`], then the client will have the default amount of time
/// to both receive the header and the body. If this is set to [`Some`], the client
/// will have the default amount of time to recieve the header, and an *additional*
/// alotment of time to recieve the body.
///
/// The default timeout for this is 30 seconds.
pub fn override_complex_body_timeout(mut self, timeout: Option<Duration>) -> Self {
self.complex_body_timeout_override = timeout;
self
}
pub async fn serve<F>(self, handler: F) -> Result<()>
where
F: Fn(Request) -> HandlerResponse + Send + Sync + 'static,
@ -165,6 +288,7 @@ impl<A: ToSocketAddrs> Builder<A> {
listener: Arc::new(listener),
handler: Arc::new(handler),
timeout: self.timeout,
complex_timeout: self.complex_body_timeout_override,
};
server.serve().await
@ -199,18 +323,6 @@ async fn receive_request(stream: &mut (impl AsyncBufRead + Unpin)) -> Result<Req
Ok(request)
}
async fn send_response(mut response: Response, stream: &mut (impl AsyncWrite + Unpin)) -> Result<()> {
send_response_header(response.header(), stream).await
.context("Failed to send response header")?;
if let Some(body) = response.take_body() {
send_response_body(body, stream).await
.context("Failed to send response body")?;
}
Ok(())
}
async fn send_response_header(header: &ResponseHeader, stream: &mut (impl AsyncWrite + Unpin)) -> Result<()> {
let header = format!(
"{status} {meta}\r\n",