fix(server): properly handle keep-alive for HTTP/1.0

Change behaviour of connection or server response when the request is
version 1.0 and the Connection: keep-alive header is not present.

1. If the response is also version 1.0, then connection is closed if the
server keep-alive header is not present.
2. If the response is version 1.1, then the keep-alive header is added
when downgrading to version 1.0.

Closes #1614

src/proto/h1/conn.rs

@@ -5,10 +5,12 @@ use std::marker::PhantomData;
 use bytes::{Buf, Bytes};
 use futures::{Async, Poll};
 use http::{HeaderMap, Method, Version};
+use http::header::{HeaderValue, CONNECTION};
 use tokio_io::{AsyncRead, AsyncWrite};
 
 use ::Chunk;
 use proto::{BodyLength, DecodedLength, MessageHead};
+use headers::connection_keep_alive;
 use super::io::{Buffered};
 use super::{EncodedBuf, Encode, Encoder, /*Decode,*/ Decoder, Http1Transaction, ParseContext};
 
@@ -438,12 +440,38 @@ where I: AsyncRead + AsyncWrite,
         }
     }
 
+    // Fix keep-alives when Connection: keep-alive header is not present
+    fn fix_keep_alive(&mut self, head: &mut MessageHead<T::Outgoing>) {
+        let outgoing_is_keep_alive = head
+            .headers
+            .get(CONNECTION)
+            .and_then(|value| Some(connection_keep_alive(value)))
+            .unwrap_or(false);
+
+        if !outgoing_is_keep_alive {
+            match head.version {
+                // If response is version 1.0 and keep-alive is not present in the response,
+                // disable keep-alive so the server closes the connection
+                Version::HTTP_10 => self.state.disable_keep_alive(),
+                // If response is version 1.1 and keep-alive is wanted, add
+                // Connection: keep-alive header when not present
+                Version::HTTP_11 => if self.state.wants_keep_alive() {
+                    head.headers
+                        .insert(CONNECTION, HeaderValue::from_static("keep-alive"));
+                },
+                _ => (),
+            }
+        }
+    }
+
     // If we know the remote speaks an older version, we try to fix up any messages
     // to work with our older peer.
     fn enforce_version(&mut self, head: &mut MessageHead<T::Outgoing>) {
 
         match self.state.version {
             Version::HTTP_10 => {
+                // Fixes response or connection when keep-alive header is not present
+                self.fix_keep_alive(head);
                 // If the remote only knows HTTP/1.0, we should force ourselves
                 // to do only speak HTTP/1.0 as well.
                 head.version = Version::HTTP_10;

tests/server.rs

@@ -30,7 +30,7 @@ use tokio::reactor::Handle;
 use tokio_io::{AsyncRead, AsyncWrite};
 
 
-use hyper::{Body, Request, Response, StatusCode};
+use hyper::{Body, Request, Response, StatusCode, Version};
 use hyper::client::Client;
 use hyper::server::conn::Http;
 use hyper::server::Server;
@@ -637,6 +637,7 @@ fn keep_alive() {
 fn http_10_keep_alive() {
     let foo_bar = b"foo bar baz";
     let server = serve();
+    // Response version 1.1 with no keep-alive header will downgrade to 1.0 when served
     server.reply()
         .header("content-length", foo_bar.len().to_string())
         .body(foo_bar);
@@ -658,6 +659,10 @@ fn http_10_keep_alive() {
         }
     }
 
+    // Connection: keep-alive header should be added when downgrading to a 1.0 response
+    let response = String::from_utf8(buf.to_vec()).unwrap();
+    response.contains("Connection: keep-alive\r\n");
+
     // try again!
 
     let quux = b"zar quux";
@@ -682,6 +687,69 @@ fn http_10_keep_alive() {
     }
 }
 
+#[test]
+fn http_10_close_on_no_ka() {
+    let foo_bar = b"foo bar baz";
+    let server = serve();
+
+    // A server response with version 1.0 but no keep-alive header
+    server
+        .reply()
+        .version(Version::HTTP_10)
+        .header("content-length", foo_bar.len().to_string())
+        .body(foo_bar);
+    let mut req = connect(server.addr());
+
+    // The client request with version 1.0 that may have the keep-alive header
+    req.write_all(
+        b"\
+        GET / HTTP/1.0\r\n\
+        Host: example.domain\r\n\
+        Connection: keep-alive\r\n\
+        \r\n\
+    ",
+    ).expect("writing 1");
+
+    let mut buf = [0; 1024 * 8];
+    loop {
+        let n = req.read(&mut buf[..]).expect("reading 1");
+        if n < buf.len() {
+            if &buf[n - foo_bar.len()..n] == foo_bar {
+                break;
+            } else {
+            }
+        }
+    }
+
+    // try again!
+
+    let quux = b"zar quux";
+    server
+        .reply()
+        .header("content-length", quux.len().to_string())
+        .body(quux);
+
+    // the write can possibly succeed, since it fills the kernel buffer on the first write
+    let _ = req.write_all(
+        b"\
+        GET /quux HTTP/1.1\r\n\
+        Host: example.domain\r\n\
+        Connection: close\r\n\
+        \r\n\
+    ",
+    );
+
+    let mut buf = [0; 1024 * 8];
+    match req.read(&mut buf[..]) {
+        // Ok(0) means EOF, so a proper shutdown
+        // Err(_) could mean ConnReset or something, also fine
+        Ok(0) | Err(_) => {}
+        Ok(n) => {
+            panic!("read {} bytes on a disabled keep-alive socket", n);
+        }
+    }
+}
+
 #[test]
 fn disable_keep_alive() {
     let foo_bar = b"foo bar baz";