Introduce Request::timeout to override agent's config

src/request.rs

@@ -40,6 +40,7 @@ pub struct Request {
     error_on_non_2xx: bool,
     headers: Vec<Header>,
     query_params: Vec<(String, String)>,
+    timeout: Option<time::Duration>,
 }
 
 impl fmt::Display for Urlish {
@@ -70,6 +71,7 @@ impl Request {
             headers: vec![],
             error_on_non_2xx: true,
             query_params: vec![],
+            timeout: None,
         }
     }
 
@@ -81,9 +83,17 @@ impl Request {
             headers: vec![],
             error_on_non_2xx: true,
             query_params: vec![],
+            timeout: None,
         }
     }
 
+    #[inline(always)]
+    /// Sets overall timeout for the request, overriding agent's configuration if any.
+    pub fn timeout(mut self, timeout: time::Duration) -> Self {
+        self.timeout = Some(timeout);
+        self
+    }
+
     /// Sends the request with no body and blocks the caller until done.
     ///
     /// Use this with GET, HEAD, OPTIONS or TRACE. It sends neither
@@ -116,7 +126,7 @@ impl Request {
         for (name, value) in self.query_params.clone() {
             url.query_pairs_mut().append_pair(&name, &value);
         }
-        let deadline = match self.agent.config.timeout {
+        let deadline = match self.timeout.or(self.agent.config.timeout) {
             None => None,
             Some(timeout) => {
                 let now = time::Instant::now();

src/test/timeout.rs

@@ -124,6 +124,27 @@ fn overall_timeout_during_headers() {
     .expect("expected timeout but got something else");
 }
 
+#[test]
+fn overall_timeout_override_during_headers() {
+    // Start a test server on an available port, that dribbles out a response at 1 write per 10ms.
+    let server = TestServer::new(dribble_headers_respond);
+    let url = format!("http://localhost:{}/", server.port);
+    let agent = builder().timeout(Duration::from_secs(90000)).build();
+    let result = agent.get(&url).timeout(Duration::from_millis(500)).call();
+    match result {
+        Ok(_) => Err("successful response".to_string()),
+        Err(e) if e.kind() == ErrorKind::Io => {
+            let ioe: Option<&io::Error> = e.source().and_then(|s| s.downcast_ref());
+            match ioe {
+                Some(e) if e.kind() == io::ErrorKind::TimedOut => Ok(()),
+                _ => Err(format!("wrong error type {:?}", e)),
+            }
+        }
+        Err(e) => Err(format!("Unexpected error type: {:?}", e)),
+    }
+    .expect("expected timeout but got something else");
+}
+
 #[test]
 #[cfg(feature = "json")]
 fn overall_timeout_reading_json() {