python: Add convenient construction of rawPayload messages

Author: svix-jplatte

python/svix/api.py

@@ -1162,6 +1162,36 @@ def expunge_content(self, app_id: str, msg_id: str) -> None:
         )
 
 
+def message_in_raw(
+    event_type: str, payload: str, content_type: t.Optional[str]
+) -> MessageIn:
+    """
+    Creates a `MessageIn` with the payload already being serialized.
+
+    The payload is not normalized on the server (usually whitespace outside
+    of string literals, unnecessarily escaped characters in string and such
+    are fixed up by the server), and is not even required to be JSON.
+
+    Args:
+        payload (str): Serialized message payload
+        content_type (str?): Content type of the payload to send as a header.
+            Defaults to `application/json`.
+
+    See the class documentation for details about the other parameters.
+    """
+    transformations_params: t.Dict[str, t.Any] = {
+        "rawPayload": payload,
+    }
+    if content_type is not None:
+        transformations_params["headers"] = {"content-type": content_type}
+
+    return MessageIn(
+        event_type=event_type,
+        payload={},
+        transformations_params=transformations_params,
+    )
+
+
 class MessageAttemptAsync(ApiBase):
     async def list_by_msg(
         self,