fix(server): skip automatic Content-Length header for HTTP 304 responses

Closes hyperium#1797

src/proto/h1/role.rs

@@ -476,14 +476,20 @@ impl Http1Transaction for Server {
  },
  None |
  Some(BodyLength::Known(0)) => {
- extend(dst, b"content-length: 0\r\n");
+ if msg.head.subject != StatusCode::NOT_MODIFIED {
+ extend(dst, b"content-length: 0\r\n");
+ }
  Encoder::length(0)
  },
  Some(BodyLength::Known(len)) => {
- extend(dst, b"content-length: ");
- let _ = ::itoa::write(&mut dst, len);
- extend(dst, b"\r\n");
- Encoder::length(len)
+ if msg.head.subject == StatusCode::NOT_MODIFIED {
+ Encoder::length(0)
+ } else {
+ extend(dst, b"content-length: ");
+ let _ = ::itoa::write(&mut dst, len);
+ extend(dst, b"\r\n");
+ Encoder::length(len)
+ }
  },
  };
  }
@@ -1583,4 +1589,3 @@ mod tests {
  })
  }
 }
-

tests/server.rs

@@ -1687,6 +1687,51 @@ fn http2_service_poll_ready_error_sends_goaway() {
  assert_eq!(h2_err.reason(), Some(h2::Reason::INADEQUATE_SECURITY));
 }
 
+#[test]
+fn skips_content_length_for_304_responses() {
+ let server = serve();
+ server.reply()
+
+ .status(hyper::StatusCode::NOT_MODIFIED)
+ .body("foo");
+ let mut req = connect(server.addr());
+ req.write_all(b"\
+ GET / HTTP/1.1\r\n\
+ Host: example.domain\r\n\
+ Connection: close\r\n\
+ \r\n\
+ ").unwrap();
+
+ let mut response = String::new();
+ req.read_to_string(&mut response).unwrap();
+ assert!(!response.contains("content-length:"));
+}
+
+#[test]
+fn skips_content_length_and_body_for_304_responses() {
+ let server = serve();
+ server.reply()
+
+ .status(hyper::StatusCode::NOT_MODIFIED)
+ .body("foo");
+ let mut req = connect(server.addr());
+ req.write_all(b"\
+ GET / HTTP/1.1\r\n\
+ Host: example.domain\r\n\
+ Connection: close\r\n\
+ \r\n\
+ ").unwrap();
+
+ let mut response = String::new();
+ req.read_to_string(&mut response).unwrap();
+ assert!(!response.contains("content-length:"));
+ let mut lines = response.lines();
+ assert_eq!(lines.next(), Some("HTTP/1.1 304 Not Modified"));
+
+ let mut lines = lines.skip_while(|line| !line.is_empty());
+ assert_eq!(lines.next(), Some(""));
+ assert_eq!(lines.next(), None);
+}
 // -------------------------------------------------
 // the Server that is used to run all the tests with
 // -------------------------------------------------
@@ -2058,4 +2103,3 @@ impl Drop for Dropped {
  self.0.store(true, Ordering::SeqCst);
  }
 }
-