Merge pull request #4419 from systeminit/fnichol/naxum-extractor-requ…

…ired-reply

feat(naxum): add `RequiredReply` extractor

lib/naxum/src/extract/message_parts.rs

@@ -10,7 +10,10 @@ use crate::{
     MessageHead,
 };
 
-use super::{rejection::StringRejection, FromMessage, FromMessageHead};
+use super::{
+    rejection::{NoReplyRejection, StringRejection},
+    FromMessage, FromMessageHead,
+};
 
 #[async_trait]
 impl<S, R> FromMessage<S, R> for R
@@ -45,6 +48,17 @@ impl<S> FromMessageHead<S> for Reply {
     }
 }
 
+pub struct RequiredReply(pub Subject);
+
+#[async_trait]
+impl<S> FromMessageHead<S> for RequiredReply {
+    type Rejection = NoReplyRejection;
+
+    async fn from_message_head(head: &mut Head, _state: &S) -> Result<Self, Self::Rejection> {
+        Ok(Self(head.reply.clone().ok_or(NoReplyRejection)?))
+    }
+}
+
 pub struct Headers(pub Option<HeaderMap>);
 
 #[async_trait]

lib/naxum/src/extract/rejection.rs

@@ -72,6 +72,15 @@ impl error::Error for StringRejection {
     }
 }
 
+define_rejection! {
+    #[status_code = 400]
+    #[body = "Reply was required for message but none was found"]
+    /// Rejection type for [`RequiredReply`].
+    ///
+    /// This rejection is used if a reply was expected on a message but one was not provided.
+    pub struct NoReplyRejection;
+}
+
 define_rejection! {
     #[status_code = 422]
     #[body = "Failed to deserialize the JSON body into the target type"]