feat: Add Connector trait

Cargo.toml

@@ -59,6 +59,7 @@ serde = { version = "1", features = ["derive"] }
 env_logger = "0.10"
 rustls = { version = "0.22.0" }
 rustls-pemfile = { version = "2.0" }
+socket2 = "0.5"
 
 [[example]]
 name = "cureq"

examples/bind_connect.rs

@@ -0,0 +1,52 @@
+use socket2::{Domain, Socket, Type};
+use std::net::SocketAddr;
+use ureq::Connector;
+
+#[derive(Debug)]
+pub(crate) struct BindConnector {
+    bind_addr: SocketAddr,
+}
+
+impl BindConnector {
+    pub fn new_bind(bind_addr: SocketAddr) -> Self {
+        Self { bind_addr }
+    }
+}
+
+impl Connector for BindConnector {
+    fn connect(&self, addr: &std::net::SocketAddr) -> std::io::Result<std::net::TcpStream> {
+        let socket = Socket::new(Domain::for_address(addr.to_owned()), Type::STREAM, None)?;
+        socket.bind(&self.bind_addr.into())?;
+        socket.connect(&addr.to_owned().into())?;
+        Ok(socket.into())
+    }
+
+    fn connect_timeout(
+        &self,
+        addr: &std::net::SocketAddr,
+        timeout: std::time::Duration,
+    ) -> std::io::Result<std::net::TcpStream> {
+        let socket = Socket::new(Domain::for_address(addr.to_owned()), Type::STREAM, None)?;
+        socket.bind(&self.bind_addr.into())?;
+        socket.connect_timeout(&addr.to_owned().into(), timeout)?;
+        Ok(socket.into())
+    }
+}
+
+pub fn main() {
+    let agent = ureq::builder()
+        .connector(BindConnector::new_bind("127.0.0.1:54321".parse().unwrap()))
+        .build();
+
+    let result = agent.get("http://127.0.0.1:8080/").call();
+
+    match result {
+        Err(err) => {
+            println!("{:?}", err);
+            std::process::exit(1);
+        }
+        Ok(response) => {
+            assert_eq!(response.status(), 200);
+        }
+    }
+}

src/agent.rs

@@ -4,6 +4,7 @@ use std::sync::Arc;
 use std::time::Duration;
 use url::Url;
 
+use crate::connect::{ArcConnector, StdTcpConnector};
 use crate::middleware::Middleware;
 use crate::pool::ConnectionPool;
 use crate::proxy::Proxy;
@@ -45,6 +46,7 @@ pub struct AgentBuilder {
     #[cfg(feature = "cookies")]
     cookie_store: Option<CookieStore>,
     resolver: ArcResolver,
+    connector: ArcConnector,
     middleware: Vec<Box<dyn Middleware>>,
 }
 
@@ -126,6 +128,7 @@ pub(crate) struct AgentState {
     #[cfg(feature = "cookies")]
     pub(crate) cookie_tin: CookieTin,
     pub(crate) resolver: ArcResolver,
+    pub(crate) connector: ArcConnector,
     pub(crate) middleware: Vec<Box<dyn Middleware>>,
 }
 
@@ -271,6 +274,7 @@ impl AgentBuilder {
             max_idle_connections: DEFAULT_MAX_IDLE_CONNECTIONS,
             max_idle_connections_per_host: DEFAULT_MAX_IDLE_CONNECTIONS_PER_HOST,
             resolver: StdResolver.into(),
+            connector: StdTcpConnector.into(),
             #[cfg(feature = "cookies")]
             cookie_store: None,
             middleware: vec![],
@@ -298,6 +302,7 @@ impl AgentBuilder {
                 #[cfg(feature = "cookies")]
                 cookie_tin: CookieTin::new(self.cookie_store.unwrap_or_else(CookieStore::default)),
                 resolver: self.resolver,
+                connector: self.connector,
                 middleware: self.middleware,
             }),
         }
@@ -402,6 +407,16 @@ impl AgentBuilder {
         self
     }
 
+    /// Configures a custom connector to be used by this agent. By default,
+    /// tcp-connect is done by std::net::TcpStream. This allows you
+    /// to override that connection with your own alternative.
+    ///
+    /// See `examples/bind_connect.rs` for example.
+    pub fn connector(mut self, connector: impl crate::Connector + 'static) -> Self {
+        self.connector = connector.into();
+        self
+    }
+
     /// Timeout for the socket connection to be successful.
     /// If both this and `.timeout()` are both set, `.timeout_connect()`
     /// takes precedence.

src/connect.rs

@@ -0,0 +1,47 @@
+use std::fmt;
+use std::io::Result as IoResult;
+use std::net::{SocketAddr, TcpStream};
+use std::sync::Arc;
+use std::time::Duration;
+
+/// A custom Connector to override the default TcpStream connector.
+pub trait Connector: Send + Sync {
+    fn connect(&self, addr: &SocketAddr) -> IoResult<TcpStream> {
+        TcpStream::connect(addr)
+    }
+
+    fn connect_timeout(&self, addr: &SocketAddr, timeout: Duration) -> IoResult<TcpStream> {
+        TcpStream::connect_timeout(addr, timeout)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct StdTcpConnector;
+
+impl Connector for StdTcpConnector {}
+
+#[derive(Clone)]
+pub(crate) struct ArcConnector(Arc<dyn Connector>);
+
+impl<R> From<R> for ArcConnector
+where
+    R: Connector + 'static,
+{
+    fn from(r: R) -> Self {
+        Self(Arc::new(r))
+    }
+}
+
+impl fmt::Debug for ArcConnector {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "ArcConnector(...)")
+    }
+}
+
+impl std::ops::Deref for ArcConnector {
+    type Target = dyn Connector;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.as_ref()
+    }
+}

src/lib.rs

@@ -357,6 +357,7 @@
 mod agent;
 mod body;
 mod chunked;
+mod connect;
 mod error;
 mod header;
 mod middleware;
@@ -429,6 +430,7 @@ mod http_crate;
 pub use crate::agent::Agent;
 pub use crate::agent::AgentBuilder;
 pub use crate::agent::RedirectAuthHeaders;
+pub use crate::connect::Connector;
 pub use crate::error::{Error, ErrorKind, OrAnyStatus, Transport};
 pub use crate::middleware::{Middleware, MiddlewareNext};
 pub use crate::proxy::Proxy;

src/stream.rs

@@ -406,9 +406,9 @@ pub(crate) fn connect_host(
                 proto.unwrap(),
             )
         } else if let Some(timeout) = timeout {
-            TcpStream::connect_timeout(&sock_addr, timeout)
+            unit.connector().connect_timeout(&sock_addr, timeout)
         } else {
-            TcpStream::connect(sock_addr)
+            unit.connector().connect(&sock_addr)
         };
 
         if let Ok(stream) = stream {

src/unit.rs

@@ -12,6 +12,7 @@ use cookie::Cookie;
 
 use crate::agent::RedirectAuthHeaders;
 use crate::body::{self, BodySize, Payload, SizedReader};
+use crate::connect::ArcConnector;
 use crate::error::{Error, ErrorKind};
 use crate::header;
 use crate::header::{get_header, Header};
@@ -115,6 +116,10 @@ impl Unit {
         self.agent.state.resolver.clone()
     }
 
+    pub fn connector(&self) -> ArcConnector {
+        self.agent.state.connector.clone()
+    }
+
     #[cfg(test)]
     pub fn header(&self, name: &str) -> Option<&str> {
         header::get_header(&self.headers, name)