feat(h1): implement obsolete line folding

Cargo.toml

@@ -30,7 +30,7 @@ futures-util = { version = "0.3", default-features = false }
 http = "0.2"
 http-body = "0.4"
 httpdate = "1.0"
-httparse = "1.5.1"
+httparse = "1.6"
 h2 = { version = "0.3.9", optional = true }
 itoa = "1"
 tracing = { version = "0.1", default-features = false, features = ["std"] }

src/client/client.rs

@@ -1000,6 +1000,9 @@ impl Builder {
     /// Set whether HTTP/1 connections will accept spaces between header names
     /// and the colon that follow them in responses.
     ///
+    /// Newline codepoints (`\r` and `\n`) will be transformed to spaces when
+    /// parsing.
+    ///
     /// You probably don't need this, here is what [RFC 7230 Section 3.2.4.] has
     /// to say about it:
     ///
@@ -1022,6 +1025,43 @@ impl Builder {
         self
     }
 
+    /// Set whether HTTP/1 connections will accept obsolete line folding for
+    /// header values.
+    ///
+    /// You probably don't need this, here is what [RFC 7230 Section 3.2.4.] has
+    /// to say about it:
+    ///
+    /// > A server that receives an obs-fold in a request message that is not
+    /// > within a message/http container MUST either reject the message by
+    /// > sending a 400 (Bad Request), preferably with a representation
+    /// > explaining that obsolete line folding is unacceptable, or replace
+    /// > each received obs-fold with one or more SP octets prior to
+    /// > interpreting the field value or forwarding the message downstream.
+    ///
+    /// > A proxy or gateway that receives an obs-fold in a response message
+    /// > that is not within a message/http container MUST either discard the
+    /// > message and replace it with a 502 (Bad Gateway) response, preferably
+    /// > with a representation explaining that unacceptable line folding was
+    /// > received, or replace each received obs-fold with one or more SP
+    /// > octets prior to interpreting the field value or forwarding the
+    /// > message downstream.
+    ///
+    /// > A user agent that receives an obs-fold in a response message that is
+    /// > not within a message/http container MUST replace each received
+    /// > obs-fold with one or more SP octets prior to interpreting the field
+    /// > value.
+    ///
+    /// Note that this setting does not affect HTTP/2.
+    ///
+    /// Default is false.
+    ///
+    /// [RFC 7230 Section 3.2.4.]: https://tools.ietf.org/html/rfc7230#section-3.2.4
+    pub fn http1_allow_obsolete_multiline_headers_in_responses(&mut self, val: bool) -> &mut Self {
+        self.conn_builder
+            .http1_allow_obsolete_multiline_headers_in_responses(val);
+        self
+    }
+
     /// Set whether HTTP/1 connections should try to use vectored writes,
     /// or always flatten into a single buffer.
     ///

src/client/conn.rs

@@ -598,6 +598,49 @@ impl Builder {
         self
     }
 
+    /// Set whether HTTP/1 connections will accept obsolete line folding for
+    /// header values.
+    ///
+    /// Newline codepoints (`\r` and `\n`) will be transformed to spaces when
+    /// parsing.
+    ///
+    /// You probably don't need this, here is what [RFC 7230 Section 3.2.4.] has
+    /// to say about it:
+    ///
+    /// > A server that receives an obs-fold in a request message that is not
+    /// > within a message/http container MUST either reject the message by
+    /// > sending a 400 (Bad Request), preferably with a representation
+    /// > explaining that obsolete line folding is unacceptable, or replace
+    /// > each received obs-fold with one or more SP octets prior to
+    /// > interpreting the field value or forwarding the message downstream.
+    ///
+    /// > A proxy or gateway that receives an obs-fold in a response message
+    /// > that is not within a message/http container MUST either discard the
+    /// > message and replace it with a 502 (Bad Gateway) response, preferably
+    /// > with a representation explaining that unacceptable line folding was
+    /// > received, or replace each received obs-fold with one or more SP
+    /// > octets prior to interpreting the field value or forwarding the
+    /// > message downstream.
+    ///
+    /// > A user agent that receives an obs-fold in a response message that is
+    /// > not within a message/http container MUST replace each received
+    /// > obs-fold with one or more SP octets prior to interpreting the field
+    /// > value.
+    ///
+    /// Note that this setting does not affect HTTP/2.
+    ///
+    /// Default is false.
+    ///
+    /// [RFC 7230 Section 3.2.4.]: https://tools.ietf.org/html/rfc7230#section-3.2.4
+    pub fn http1_allow_obsolete_multiline_headers_in_responses(
+        &mut self,
+        enabled: bool,
+    ) -> &mut Builder {
+        self.h1_parser_config
+            .allow_obsolete_multiline_headers_in_responses(enabled);
+        self
+    }
+
     /// Set whether HTTP/1 connections should try to use vectored writes,
     /// or always flatten into a single buffer.
     ///

src/proto/h1/role.rs

@@ -955,7 +955,21 @@ impl Http1Transaction for Client {
                 }
             };
 
-            let slice = buf.split_to(len).freeze();
+            let mut slice = buf.split_to(len);
+
+            if ctx.h1_parser_config.obsolete_multiline_headers_in_responses_are_allowed() {
+                for header in &headers_indices[..headers_len] {
+                    // SAFETY: array is valid up to `headers_len`
+                    let header = unsafe { &*header.as_ptr() };
+                    for b in &mut slice[header.value.0..header.value.1] {
+                        if *b == b'\r' || *b == b'\n' {
+                            *b = b' ';
+                        }
+                    }
+                }
+            }
+
+            let slice = slice.freeze();
 
             let mut headers = ctx.cached_headers.take().unwrap_or_else(HeaderMap::new);
 

tests/client.rs

@@ -2214,6 +2214,63 @@ mod conn {
         future::join(server, client).await;
     }
 
+    #[tokio::test]
+    async fn get_obsolete_line_folding() {
+        let _ = ::pretty_env_logger::try_init();
+        let listener = TkTcpListener::bind(SocketAddr::from(([127, 0, 0, 1], 0)))
+            .await
+            .unwrap();
+        let addr = listener.local_addr().unwrap();
+
+        let server = async move {
+            let mut sock = listener.accept().await.unwrap().0;
+            let mut buf = [0; 4096];
+            let n = sock.read(&mut buf).await.expect("read 1");
+
+            // Notably:
+            // - Just a path, since just a path was set
+            // - No host, since no host was set
+            let expected = "GET /a HTTP/1.1\r\n\r\n";
+            assert_eq!(s(&buf[..n]), expected);
+
+            sock.write_all(b"HTTP/1.1 200 OK\r\nContent-Length: \r\n 0\r\nLine-Folded-Header: hello\r\n world \r\n \r\n\r\n")
+                .await
+                .unwrap();
+        };
+
+        let client = async move {
+            let tcp = tcp_connect(&addr).await.expect("connect");
+            let (mut client, conn) = conn::Builder::new()
+                .http1_allow_obsolete_multiline_headers_in_responses(true)
+                .handshake::<_, Body>(tcp)
+                .await
+                .expect("handshake");
+
+            tokio::task::spawn(async move {
+                conn.await.expect("http conn");
+            });
+
+            let req = Request::builder()
+                .uri("/a")
+                .body(Default::default())
+                .unwrap();
+            let mut res = client.send_request(req).await.expect("send_request");
+            assert_eq!(res.status(), hyper::StatusCode::OK);
+            assert_eq!(res.headers().len(), 2);
+            assert_eq!(
+                res.headers().get(http::header::CONTENT_LENGTH).unwrap(),
+                "0"
+            );
+            assert_eq!(
+                res.headers().get("line-folded-header").unwrap(),
+                "hello   world"
+            );
+            assert!(res.body_mut().next().await.is_none());
+        };
+
+        future::join(server, client).await;
+    }
+
     #[test]
     fn incoming_content_length() {
         use hyper::body::HttpBody;