Trim whitespace from chat messages and limit their length

Add a way for the server to respond to any request with an error

zrpc/src/peer.rs

@@ -238,8 +238,12 @@ impl Peer {
                 .recv()
                 .await
                 .ok_or_else(|| anyhow!("connection was closed"))?;
-            T::Response::from_envelope(response)
-                .ok_or_else(|| anyhow!("received response of the wrong type"))
+            if let Some(proto::envelope::Payload::Error(error)) = &response.payload {
+                Err(anyhow!("request failed").context(error.message.clone()))
+            } else {
+                T::Response::from_envelope(response)
+                    .ok_or_else(|| anyhow!("received response of the wrong type"))
+            }
         }
     }
 
@@ -301,6 +305,25 @@ impl Peer {
         }
     }
 
+    pub fn respond_with_error<T: RequestMessage>(
+        self: &Arc<Self>,
+        receipt: Receipt<T>,
+        response: proto::Error,
+    ) -> impl Future<Output = Result<()>> {
+        let this = self.clone();
+        async move {
+            let mut connection = this.connection(receipt.sender_id).await?;
+            let message_id = connection
+                .next_message_id
+                .fetch_add(1, atomic::Ordering::SeqCst);
+            connection
+                .outgoing_tx
+                .send(response.into_envelope(message_id, Some(receipt.message_id), None))
+                .await?;
+            Ok(())
+        }
+    }
+
     fn connection(
         self: &Arc<Self>,
         connection_id: ConnectionId,

zrpc/src/proto.rs

@@ -125,6 +125,7 @@ messages!(
     ChannelMessageSent,
     CloseBuffer,
     CloseWorktree,
+    Error,
     GetChannelMessages,
     GetChannelMessagesResponse,
     GetChannels,