Support to set header names of `ClientRequest` as Camel-Case

This is the case for supporting to request for servers which don't
perfectly implement the `RFC 7230`. It is important for an app
which uses `ClientRequest` as core part.

* Add field `upper_camel_case_headers` to `ClientRequest`.

* Add function `set_upper_camel_case_headers` to `ClientRequest`
  and `ClientRequestBuilder` to set field `upper_camel_case_headers`.

* Add trait `client::writer::UpperCamelCaseHeader` for
  `http::header::HeaderName`, let it can be converted to Camel-Case
  then writed to buffer.

* Add test `test_client::test_upper_camel_case_headers`.

src/client/request.rs

@@ -54,6 +54,7 @@ pub struct ClientRequest {
     method: Method,
     version: Version,
     headers: HeaderMap,
+    upper_camel_case_headers: bool,
     body: Body,
     chunked: bool,
     upgrade: bool,
@@ -77,6 +78,7 @@ impl Default for ClientRequest {
             method: Method::default(),
             version: Version::HTTP_11,
             headers: HeaderMap::with_capacity(16),
+            upper_camel_case_headers: false,
             body: Body::Empty,
             chunked: false,
             upgrade: false,
@@ -190,6 +192,19 @@ impl ClientRequest {
         &mut self.headers
     }
 
+    /// is to uppercase headers with Camel-Case
+    /// default is `false`
+    #[inline]
+    pub fn upper_camel_case_headers(&self) -> bool {
+        self.upper_camel_case_headers
+    }
+
+    /// Set `true` to send headers which are uppercased with Camel-Case.
+    #[inline]
+    pub fn set_upper_camel_case_headers(&mut self, value: bool) {
+        self.upper_camel_case_headers = value;
+    }
+
     /// is chunked encoding enabled
     #[inline]
     pub fn chunked(&self) -> bool {
@@ -439,6 +454,15 @@ impl ClientRequestBuilder {
         self
     }
 
+    /// Set `true` to send headers which are uppercased with Camel-Case.
+    #[inline]
+    pub fn set_upper_camel_case_headers(&mut self, value: bool) -> &mut Self {
+        if let Some(parts) = parts(&mut self.request, &self.err) {
+            parts.upper_camel_case_headers = value;
+        }
+        self
+    }
+
     /// Set content encoding.
     ///
     /// By default `ContentEncoding::Identity` is used.

src/client/writer.rs

@@ -16,7 +16,7 @@ use flate2::write::{GzEncoder, ZlibEncoder};
 use flate2::Compression;
 use futures::{Async, Poll};
 use http::header::{
-    HeaderValue, CONNECTION, CONTENT_ENCODING, CONTENT_LENGTH, DATE, TRANSFER_ENCODING,
+    HeaderName, HeaderValue, CONNECTION, CONTENT_ENCODING, CONTENT_LENGTH, DATE, TRANSFER_ENCODING,
 };
 use http::{HttpTryFrom, Version};
 use time::{self, Duration};
@@ -142,14 +142,27 @@ impl HttpClientWriter {
                 buffer.reserve(msg.headers().len() * AVERAGE_HEADER_SIZE);
             }
 
-            for (key, value) in msg.headers() {
-                let v = value.as_ref();
-                let k = key.as_str().as_bytes();
-                buffer.reserve(k.len() + v.len() + 4);
-                buffer.put_slice(k);
-                buffer.put_slice(b": ");
-                buffer.put_slice(v);
-                buffer.put_slice(b"\r\n");
+            // to use Camel-Case headers
+            if msg.upper_camel_case_headers() {
+                for (key, value) in msg.headers() {
+                    let v = value.as_ref();
+                    let k = key.as_str().as_bytes();
+                    buffer.reserve(k.len() + v.len() + 4);
+                    key.to_upper_camel_case(buffer);
+                    buffer.put_slice(b": ");
+                    buffer.put_slice(v);
+                    buffer.put_slice(b"\r\n");
+                }
+            } else {
+                for (key, value) in msg.headers() {
+                    let v = value.as_ref();
+                    let k = key.as_str().as_bytes();
+                    buffer.reserve(k.len() + v.len() + 4);
+                    buffer.put_slice(k);
+                    buffer.put_slice(b": ");
+                    buffer.put_slice(v);
+                    buffer.put_slice(b"\r\n");
+                }
             }
 
             // set date header
@@ -216,6 +229,38 @@ impl HttpClientWriter {
     }
 }
 
+trait UpperCamelCaseHeader {
+    fn to_upper_camel_case(&self, buffer: &mut BytesMut);
+}
+
+impl UpperCamelCaseHeader for HeaderName {
+
+    /// Let header name to be as upper Camel-Case, then write it to buffer.
+    fn to_upper_camel_case(&self, buffer: &mut BytesMut) {
+        let key = self.as_str().as_bytes();
+        let mut key_iter = key.iter();
+
+        if let Some(c) = key_iter.next() {
+            if *c >= b'a' && *c <= b'z' {
+                buffer.put_slice(&[*c ^ b' ']);
+            }
+        } else {
+            return;
+        }
+
+        while let Some(c) = key_iter.next() {
+            buffer.put_slice(&[*c]);
+            if *c == b'-' {
+                if let Some(c) = key_iter.next() {
+                    if *c >= b'a' && *c <= b'z' {
+                        buffer.put_slice(&[*c ^ b' ']);
+                    }
+                }
+            }
+        }
+    }
+}
+
 fn content_encoder(buf: BytesMut, req: &mut ClientRequest) -> Output {
     let version = req.version();
     let mut body = req.replace_body(Body::Empty);

tests/test_client.rs

@@ -11,7 +11,7 @@ extern crate tokio_uds;
 use std::io::{Read, Write};
 use std::{net, thread};
 
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut, BufMut};
 use flate2::read::GzDecoder;
 use futures::stream::once;
 use futures::Future;
@@ -477,6 +477,42 @@ fn test_default_headers() {
     )));
 }
 
+#[test]
+fn test_upper_camel_case_headers() {
+    let addr = test::TestServer::unused_addr();
+
+    thread::spawn(move || {
+        let lst = net::TcpListener::bind(addr).unwrap();
+
+        for stream in lst.incoming() {
+            let mut stream = stream.unwrap();
+            let mut b = [0; 1000];
+            let _ = stream.read(&mut b).unwrap();
+            let mut v = BytesMut::from("HTTP/1.1 200 OK\r\nconnection: close\r\n\r\n");
+            v.reserve(b.len());
+            v.put_slice(&b);
+            let _ = stream.write_all(&v);
+        }
+    });
+
+    let mut sys = actix::System::new("test");
+
+    // client request
+    let req = client::ClientRequest::get(format!("http://{}/", addr).as_str())
+        .header("User-Agent", "test")
+        .header("Accept-Encoding", "over_test")
+        .no_default_headers()
+        .set_upper_camel_case_headers(true)
+        .finish()
+        .unwrap();
+    let response = sys.block_on(req.send()).unwrap();
+    assert!(response.status().is_success());
+
+    // read response
+    let bytes = sys.block_on(response.body()).unwrap();
+    assert_eq!(&&bytes[..62], &&b"GET / HTTP/1.1\r\nUser-Agent: test\r\nAccept-Encoding: over_test\r\n"[..]);
+}
+
 #[test]
 fn client_read_until_eof() {
     let addr = test::TestServer::unused_addr();