fix improper handling of request body backpressure

Closes #348

tests/multipart.rs

@@ -49,3 +49,52 @@ fn test_multipart() {
     assert_eq!(res.url().as_str(), &url);
     assert_eq!(res.status(), reqwest::StatusCode::OK);
 }
+
+#[test]
+fn file() {
+    let _ = env_logger::try_init();
+
+    let form = reqwest::multipart::Form::new()
+        .file("foo", "Cargo.lock").unwrap();
+
+    let fcontents = ::std::fs::read_to_string("Cargo.lock").unwrap();
+
+    let expected_body = format!("\
+        --{0}\r\n\
+        Content-Disposition: form-data; name=\"foo\"; filename=\"Cargo.lock\"\r\n\
+        Content-Type: application/octet-stream\r\n\r\n\
+        {1}\r\n\
+        --{0}--\r\n\
+    ", form.boundary(), fcontents);
+
+    let server = server! {
+        request: format!("\
+            POST /multipart/2 HTTP/1.1\r\n\
+            user-agent: $USERAGENT\r\n\
+            accept: */*\r\n\
+            content-type: multipart/form-data; boundary={}\r\n\
+            content-length: {}\r\n\
+            accept-encoding: gzip\r\n\
+            host: $HOST\r\n\
+            \r\n\
+            {}\
+            ", form.boundary(), expected_body.len(), expected_body),
+        response: b"\
+            HTTP/1.1 200 OK\r\n\
+            Server: multipart\r\n\
+            Content-Length: 0\r\n\
+            \r\n\
+            "
+    };
+
+    let url = format!("http://{}/multipart/2", server.addr());
+
+    let res = reqwest::Client::new()
+        .post(&url)
+        .multipart(form)
+        .send()
+        .unwrap();
+
+    assert_eq!(res.url().as_str(), &url);
+    assert_eq!(res.status(), reqwest::StatusCode::OK);
+}

tests/support/server.rs

@@ -32,7 +32,8 @@ static DEFAULT_USER_AGENT: &'static str =
 pub fn spawn(txns: Vec<Txn>) -> Server {
     let listener = net::TcpListener::bind("127.0.0.1:0").unwrap();
     let addr = listener.local_addr().unwrap();
-    thread::spawn(
+    let tname = format!("test({})-support-server", thread::current().name().unwrap_or("<unknown>"));
+    thread::Builder::new().name(tname).spawn(
         move || for txn in txns {
             let mut expected = txn.request;
             let reply = txn.response;
@@ -46,20 +47,41 @@ pub fn spawn(txns: Vec<Txn>) -> Server {
                 thread::park_timeout(dur);
             }
 
-            let mut buf = [0; 4096];
-            assert!(buf.len() >= expected.len());
+            let mut buf = vec![0; expected.len() + 256];
 
             let mut n = 0;
             while n < expected.len() {
                 match socket.read(&mut buf[n..]) {
-                    Ok(0) | Err(_) => break,
+                    Ok(0) => break,
                     Ok(nread) => n += nread,
+                    Err(err) => {
+                        println!("server read error: {}", err);
+                        break;
+                    }
                 }
             }
 
             match (::std::str::from_utf8(&expected), ::std::str::from_utf8(&buf[..n])) {
-                (Ok(expected), Ok(received)) => assert_eq!(expected, received),
-                _ => assert_eq!(expected, &buf[..n]),
+                (Ok(expected), Ok(received)) => {
+                    assert_eq!(
+                        expected.len(),
+                        received.len(),
+                        "expected len = {}, received len = {}",
+                        expected.len(),
+                        received.len(),
+                    );
+                    assert_eq!(expected, received)
+                },
+                _ => {
+                    assert_eq!(
+                        expected.len(),
+                        n,
+                        "expected len = {}, received len = {}",
+                        expected.len(),
+                        n,
+                    );
+                    assert_eq!(expected, &buf[..n])
+                },
             }
 
             if let Some(dur) = txn.response_timeout {
@@ -86,7 +108,7 @@ pub fn spawn(txns: Vec<Txn>) -> Server {
                 socket.write_all(&reply).unwrap();
             }
         }
-    );
+    ).expect("server thread spawn");
 
     Server {
         addr: addr,