Implemented the POST /marketplace/orders/{order_id}/messages endpoint for the Open API specification document in the library target.

Sources/DiscogsService/openapi.yaml

@@ -2116,7 +2116,7 @@ paths:
       description: |
         Returns a list orders for a seller in a marketplace. 
       
-        This endpoints accepts pagination and authentication as a seller.
+        This endpoints accepts pagination and requires authentication as a seller.
       operationId: getOrderMessages
       parameters:
         - $ref: '#/components/parameters/OrderId'
@@ -2158,8 +2158,50 @@ paths:
           $ref: '#/components/responses/NotAccessable'
         '404':
           $ref: '#/components/responses/NotFound'
-        '422':
-          $ref: '#/components/responses/Unprocessable'
+        '500':
+          $ref: '#/components/responses/InternalError'
+    post: 
+      tags: 
+        - Marketplace
+      summary: Add a message to an order.
+      description: |
+        Adds a new message to the order’s message log.
+
+        When posting a new message, it is also possible to update the order status. In this case, the message will automatically be prepended with: *Seller changed status from Old Status to New Status*
+
+        While both `message` and `status` properties are each optional, one or both must be present.
+      
+        This endpoints requires authentication as a seller.
+      operationId: addOrderMessage
+      parameters:
+        - $ref: '#/components/parameters/OrderId'
+      requestBody:
+        $ref: '#/components/requestBodies/OrderMessage'
+      security:
+        - ConsumerKeySecret: []
+        - UserToken: []
+        - OAuth: []
+      responses:
+        '201':
+          description: Successfully added a new message to a list of messages related to an order.
+          headers:
+            X-Discogs-RateLimit:
+              $ref: '#/components/headers/RateLimit'
+            X-Discogs-RateLimit-Used:
+              $ref: '#/components/headers/RateLimitUsed'
+            X-Discogs-RateLimit-Remaining:
+              $ref: '#/components/headers/RateLimitRemaining'
+          content:
+            application/json:
+              schema:
+                description: A message that has been added to an order.
+                $ref: '#/components/schemas/OrderMessage'
+        '401':
+          $ref: '#/components/responses/Unauthorized'
+        '403':
+          $ref: '#/components/responses/NotAccessable'
+        '404':
+          $ref: '#/components/responses/NotFound'
         '500':
           $ref: '#/components/responses/InternalError'
 components:
@@ -2617,6 +2659,19 @@ components:
               - price
               - release_id
               - status
+    OrderMessage:
+      description: A container to use in case to add a message to an existing order.
+      required: true
+      content:
+        application/json:
+          schema:
+            properties:
+              message:
+                description: A message to attach to an order.
+                type: string
+              status:
+                description: A update to a status of an order.
+                type: string
     MoveInstance:
       description: A container to use in case of moving a release instance from a collection folder into another.
       required: false