fix: message topic usage

imports-request-reply.md

@@ -73,14 +73,14 @@ This allows the component to perform request/reply messaging patterns.</p>
 <li><a id="constructor_message.0"></a> own&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_topic"></a><code>[method]message.topic: func</code></h4>
-<p>The topic/subject/channel this message was received on</p>
+<p>The topic/subject/channel this message was received on, if any</p>
 <h5>Params</h5>
 <ul>
 <li><a id="method_message_topic.self"></a><code>self</code>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h5>Return values</h5>
 <ul>
-<li><a id="method_message_topic.0"></a> <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
+<li><a id="method_message_topic.0"></a> option&lt;<a href="#topic"><a href="#topic"><code>topic</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_content_type"></a><code>[method]message.content-type: func</code></h4>
 <p>An optional content-type describing the format of the data in the message. This is
@@ -168,6 +168,9 @@ included it as a core interface.</p>
 #### <a id="error"></a>`type error`
 [`error`](#error)
 <p>
+#### <a id="topic"></a>`type topic`
+[`topic`](#topic)
+<p>
 #### <a id="request_options"></a>`resource request-options`
 <h2>Options for a request/reply operation. This is a resource to allow for future expansion of
 options.</h2>
@@ -208,6 +211,7 @@ return the list of messages received up to that point.</p>
 <h5>Params</h5>
 <ul>
 <li><a id="request.c"></a><code>c</code>: borrow&lt;<a href="#client"><a href="#client"><code>client</code></a></a>&gt;</li>
+<li><a id="request.topic"></a><a href="#topic"><code>topic</code></a>: <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
 <li><a id="request.message"></a><a href="#message"><code>message</code></a>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 <li><a id="request.options"></a><code>options</code>: option&lt;own&lt;<a href="#request_options"><a href="#request_options"><code>request-options</code></a></a>&gt;&gt;</li>
 </ul>

imports.md

@@ -72,14 +72,14 @@ It includes the <code>producer</code> interface for sending messages.</p>
 <li><a id="constructor_message.0"></a> own&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_topic"></a><code>[method]message.topic: func</code></h4>
-<p>The topic/subject/channel this message was received on</p>
+<p>The topic/subject/channel this message was received on, if any</p>
 <h5>Params</h5>
 <ul>
 <li><a id="method_message_topic.self"></a><code>self</code>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h5>Return values</h5>
 <ul>
-<li><a id="method_message_topic.0"></a> <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
+<li><a id="method_message_topic.0"></a> option&lt;<a href="#topic"><a href="#topic"><code>topic</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_content_type"></a><code>[method]message.content-type: func</code></h4>
 <p>An optional content-type describing the format of the data in the message. This is

messaging-core.md

@@ -77,14 +77,14 @@ enabling the component to handle incoming messages without request/reply capabil
 <li><a id="constructor_message.0"></a> own&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_topic"></a><code>[method]message.topic: func</code></h4>
-<p>The topic/subject/channel this message was received on</p>
+<p>The topic/subject/channel this message was received on, if any</p>
 <h5>Params</h5>
 <ul>
 <li><a id="method_message_topic.self"></a><code>self</code>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h5>Return values</h5>
 <ul>
-<li><a id="method_message_topic.0"></a> <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
+<li><a id="method_message_topic.0"></a> option&lt;<a href="#topic"><a href="#topic"><code>topic</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_content_type"></a><code>[method]message.content-type: func</code></h4>
 <p>An optional content-type describing the format of the data in the message. This is

messaging-request-reply.md

@@ -79,14 +79,14 @@ handling incoming messages with request/reply capabilities.</p>
 <li><a id="constructor_message.0"></a> own&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_topic"></a><code>[method]message.topic: func</code></h4>
-<p>The topic/subject/channel this message was received on</p>
+<p>The topic/subject/channel this message was received on, if any</p>
 <h5>Params</h5>
 <ul>
 <li><a id="method_message_topic.self"></a><code>self</code>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 </ul>
 <h5>Return values</h5>
 <ul>
-<li><a id="method_message_topic.0"></a> <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
+<li><a id="method_message_topic.0"></a> option&lt;<a href="#topic"><a href="#topic"><code>topic</code></a></a>&gt;</li>
 </ul>
 <h4><a id="method_message_content_type"></a><code>[method]message.content-type: func</code></h4>
 <p>An optional content-type describing the format of the data in the message. This is
@@ -174,6 +174,9 @@ included it as a core interface.</p>
 #### <a id="error"></a>`type error`
 [`error`](#error)
 <p>
+#### <a id="topic"></a>`type topic`
+[`topic`](#topic)
+<p>
 #### <a id="request_options"></a>`resource request-options`
 <h2>Options for a request/reply operation. This is a resource to allow for future expansion of
 options.</h2>
@@ -214,6 +217,7 @@ return the list of messages received up to that point.</p>
 <h5>Params</h5>
 <ul>
 <li><a id="request.c"></a><code>c</code>: borrow&lt;<a href="#client"><a href="#client"><code>client</code></a></a>&gt;</li>
+<li><a id="request.topic"></a><a href="#topic"><code>topic</code></a>: <a href="#topic"><a href="#topic"><code>topic</code></a></a></li>
 <li><a id="request.message"></a><a href="#message"><code>message</code></a>: borrow&lt;<a href="#message"><a href="#message"><code>message</code></a></a>&gt;</li>
 <li><a id="request.options"></a><code>options</code>: option&lt;own&lt;<a href="#request_options"><a href="#request_options"><code>request-options</code></a></a>&gt;&gt;</li>
 </ul>

wit/request-reply.wit

@@ -3,7 +3,7 @@
 /// request/reply. However, request/reply is a very common pattern in messaging and as such, we have
 /// included it as a core interface.
 interface request-reply {
-    use types.{client, message, error};
+    use types.{client, message, error, topic};
 
     /// Options for a request/reply operation. This is a resource to allow for future expansion of
     /// options.
@@ -31,7 +31,7 @@ interface request-reply {
     /// error, (2) if the maximum expected number of replies were received before timeout, return
     /// the list of messages, or (3) if the timeout is reached before the expected number of replies,
     /// return the list of messages received up to that point.
-    request: func(c: borrow<client>, message: borrow<message>, options: option<request-options>) -> result<list<message>, error>;
+    request: func(c: borrow<client>, topic: topic, message: borrow<message>, options: option<request-options>) -> result<list<message>, error>;
 
     /// Replies to the given message with the given response message. The details of which topic
     /// the message is sent to is up to the implementation. This allows for reply-to details to be

wit/types.wit

@@ -26,8 +26,8 @@ interface types {
     /// A message with a binary payload and additional information
     resource message {
         constructor(data: list<u8>);
-        /// The topic/subject/channel this message was received on
-        topic: func() -> topic;
+        /// The topic/subject/channel this message was received on, if any
+        topic: func() -> option<topic>;
         /// An optional content-type describing the format of the data in the message. This is 
         /// sometimes described as the "format" type
         content-type: func() -> option<string>;