feat(request-response): add Behaviour::send_request_with_addresses()

protocols/request-response/CHANGELOG.md

@@ -3,6 +3,9 @@
 - fix: public cbor/json codec module
   See [PR 5830](https://github.com/libp2p/rust-libp2p/pull/5830).
 
+- feat: add `Behaviour::send_request_with_addresses()`
+  See [PR 5938](https://github.com/libp2p/rust-libp2p/issues/5938).
+
 ## 0.28.0
 
 - Deprecate `void` crate.

protocols/request-response/src/lib.rs

@@ -431,9 +431,24 @@ where
     /// > in another `NetworkBehaviour` that provides peer and
     /// > address discovery, or known addresses of peers must be
     /// > managed via [`libp2p_swarm::Swarm::add_peer_address`].
-    /// > Addresses are automatically removed when dial attempts
-    /// > to them fail.
+    /// > Alternatively, [`Behaviour::send_request_with_addresses`]
+    /// > can be used. Addresses are automatically removed when
+    /// > dial attempts to them fail.
     pub fn send_request(&mut self, peer: &PeerId, request: TCodec::Request) -> OutboundRequestId {
+        self.send_request_with_addresses(peer, request, Vec::new())
+    }
+
+    /// Initiates sending a request, using provided addresses if a connection needs to be
+    /// established.
+    ///
+    /// This is very similar to [`Behaviour::send_request`], but uses provided addresses when
+    /// dialing currently not connected peer.
+    pub fn send_request_with_addresses(
+        &mut self,
+        peer: &PeerId,
+        request: TCodec::Request,
+        addresses: Vec<Multiaddr>,
+    ) -> OutboundRequestId {
         let request_id = self.next_outbound_request_id();
         let request = OutboundMessage {
             request_id,
@@ -443,7 +458,10 @@ where
 
         if let Some(request) = self.try_send_request(peer, request) {
             self.pending_events.push_back(ToSwarm::Dial {
-                opts: DialOpts::peer_id(*peer).build(),
+                opts: DialOpts::peer_id(*peer)
+                    .addresses(addresses)
+                    .extend_addresses_through_behaviour()
+                    .build(),
             });
             self.pending_outbound_requests
                 .entry(*peer)

protocols/request-response/tests/ping.rs

@@ -43,10 +43,7 @@ async fn is_response_outbound() {
 
     let mut swarm1 = Swarm::new_ephemeral(|_| {
         request_response::cbor::Behaviour::<Ping, Pong>::new(
-            [(
-                StreamProtocol::new("/ping/1"),
-                request_response::ProtocolSupport::Full,
-            )],
+            [(StreamProtocol::new("/ping/1"), ProtocolSupport::Full)],
             request_response::Config::default(),
         )
     });
@@ -180,6 +177,126 @@ async fn ping_protocol() {
     peer2.await;
 }
 
+/// Exercises a simple ping protocol where peers are not connected prior to request sending.
+#[async_std::test]
+#[cfg(feature = "cbor")]
+async fn ping_protocol_explicit_address() {
+    let ping = Ping("ping".to_string().into_bytes());
+    let pong = Pong("pong".to_string().into_bytes());
+
+    let protocols = iter::once((StreamProtocol::new("/ping/1"), ProtocolSupport::Full));
+    let cfg = request_response::Config::default();
+
+    let mut swarm1 = Swarm::new_ephemeral(|_| {
+        request_response::cbor::Behaviour::<Ping, Pong>::new(protocols.clone(), cfg.clone())
+    });
+    let peer1_id = *swarm1.local_peer_id();
+    let mut swarm2 = Swarm::new_ephemeral(|_| {
+        request_response::cbor::Behaviour::<Ping, Pong>::new(protocols, cfg)
+    });
+    let peer2_id = *swarm2.local_peer_id();
+
+    let (peer1_listen_addr, _) = swarm1.listen().with_memory_addr_external().await;
+
+    let expected_ping = ping.clone();
+    let expected_pong = pong.clone();
+
+    let peer1 = async move {
+        loop {
+            match swarm1.next_swarm_event().await.try_into_behaviour_event() {
+                Ok(request_response::Event::Message {
+                    peer,
+                    message:
+                        request_response::Message::Request {
+                            request, channel, ..
+                        },
+                    ..
+                }) => {
+                    assert_eq!(&request, &expected_ping);
+                    assert_eq!(&peer, &peer2_id);
+                    swarm1
+                        .behaviour_mut()
+                        .send_response(channel, pong.clone())
+                        .unwrap();
+                }
+                Ok(request_response::Event::ResponseSent { peer, .. }) => {
+                    assert_eq!(&peer, &peer2_id);
+                }
+                Ok(e) => {
+                    panic!("Peer1: Unexpected event: {e:?}")
+                }
+                Err(..) => {}
+            }
+        }
+    };
+
+    let peer2 = async {
+        let req_id = swarm2.behaviour_mut().send_request(&peer1_id, ping.clone());
+        assert!(swarm2.behaviour().is_pending_outbound(&peer1_id, &req_id));
+
+        // Can't dial to unknown peer
+        match swarm2
+            .next_swarm_event()
+            .await
+            .try_into_behaviour_event()
+            .unwrap()
+        {
+            request_response::Event::OutboundFailure {
+                peer, request_id, ..
+            } => {
+                assert_eq!(&peer, &peer1_id);
+                assert_eq!(req_id, request_id);
+            }
+            e => panic!("Peer2: Unexpected event: {e:?}"),
+        }
+
+        let req_id = swarm2.behaviour_mut().send_request_with_addresses(
+            &peer1_id,
+            ping.clone(),
+            vec![peer1_listen_addr],
+        );
+        assert!(swarm2.behaviour().is_pending_outbound(&peer1_id, &req_id));
+
+        // Dial to peer with explicit address succeeds
+        match swarm2.select_next_some().await {
+            SwarmEvent::Dialing { peer_id, .. } => {
+                assert_eq!(&peer_id, &Some(peer1_id));
+            }
+            e => panic!("Peer2: Unexpected event: {e:?}"),
+        }
+        match swarm2.select_next_some().await {
+            SwarmEvent::ConnectionEstablished { peer_id, .. } => {
+                assert_eq!(&peer_id, &peer1_id);
+            }
+            e => panic!("Peer2: Unexpected event: {e:?}"),
+        }
+        match swarm2
+            .next_swarm_event()
+            .await
+            .try_into_behaviour_event()
+            .unwrap()
+        {
+            request_response::Event::Message {
+                peer,
+                message:
+                    request_response::Message::Response {
+                        request_id,
+                        response,
+                    },
+                ..
+            } => {
+                assert_eq!(&response, &expected_pong);
+                assert_eq!(&peer, &peer1_id);
+                assert_eq!(req_id, request_id);
+            }
+            e => panic!("Peer2: Unexpected event: {e:?}"),
+        }
+    };
+
+    async_std::task::spawn(Box::pin(peer1));
+    peer2.await;
+}
+
 #[async_std::test]
 #[cfg(feature = "cbor")]
 async fn emits_inbound_connection_closed_failure() {