mq_bridge/endpoints/
response.rs

1// src/endpoints/response.rs
2use crate::traits::{MessagePublisher, PublisherError, Sent, SentBatch};
3use crate::CanonicalMessage;
4use async_trait::async_trait;
5use std::any::Any;
6
7/// A publisher that simply returns the message it receives as a response.
8/// This is useful when used with a Handler to reflect the handler's output
9/// back to the source (e.g., for HTTP request-response).
10#[derive(Clone)]
11pub struct ResponsePublisher;
12
13#[async_trait]
14impl MessagePublisher for ResponsePublisher {
15    async fn send(&self, message: CanonicalMessage) -> Result<Sent, PublisherError> {
16        Ok(Sent::Response(message))
17    }
18
19    async fn send_batch(
20        &self,
21        messages: Vec<CanonicalMessage>,
22    ) -> Result<SentBatch, PublisherError> {
23        // Return all messages as responses
24        Ok(SentBatch::Partial {
25            responses: Some(messages),
26            failed: Vec::new(),
27        })
28    }
29
30    fn as_any(&self) -> &dyn Any {
31        self
32    }
33}
34
35#[cfg(test)]
36mod tests {
37    use super::*;
38    use crate::command_handler::CommandPublisher;
39    use crate::traits::Handled;
40
41    #[tokio::test]
42    async fn test_response_publisher_echo() {
43        let publisher = ResponsePublisher;
44        let msg = CanonicalMessage::new(b"test".to_vec(), None);
45        let result = publisher.send(msg).await.unwrap();
46
47        match result {
48            Sent::Response(r) => assert_eq!(&r.payload[..], b"test"),
49            _ => panic!("Expected Sent::Response"),
50        }
51    }
52
53    #[tokio::test]
54    async fn test_response_publisher_with_handler() {
55        // This simulates the full flow: Handler -> CommandPublisher -> ResponsePublisher -> Route
56        let response_pub = ResponsePublisher;
57
58        // A handler that modifies the message and returns it
59        let handler = |mut msg: CanonicalMessage| async move {
60            msg.payload = [b"handled: ", &msg.payload[..]].concat().into();
61            Ok(Handled::Publish(msg))
62        };
63
64        let publisher = CommandPublisher::new(response_pub, handler);
65
66        let msg = CanonicalMessage::new(b"input".to_vec(), None);
67        let result = publisher.send(msg).await.unwrap();
68
69        match result {
70            Sent::Response(r) => assert_eq!(&r.payload[..], b"handled: input"),
71            _ => panic!("Expected Sent::Response"),
72        }
73    }
74}
mq_bridge/endpoints/response.rs

mq_bridge/endpoints/
response.rs
