await request.post_body() method, closes #897

datasette/utils/asgi.py

@@ -90,8 +90,7 @@ class Request:
     def actor(self):
         return self.scope.get("actor", None)
 
-    async def post_vars(self):
-        body = []
+    async def post_body(self):
         body = b""
         more_body = True
         while more_body:
@@ -99,7 +98,10 @@ class Request:
             assert message["type"] == "http.request", message
             body += message.get("body", b"")
             more_body = message.get("more_body", False)
+        return body
 
+    async def post_vars(self):
+        body = await self.post_body()
         return dict(parse_qsl(body.decode("utf-8"), keep_blank_values=True))
 
     @classmethod

docs/internals.rst

@@ -48,11 +48,14 @@ The request object is passed to various plugin hooks. It represents an incoming
 ``.actor`` - dictionary (str -> Any) or None
     The currently authenticated actor (see :ref:`actors <authentication_actor>`), or ``None`` if the request is unauthenticated.
 
-The object also has one awaitable method:
+The object also has two awaitable methods:
 
 ``await request.post_vars()`` - dictionary
     Returns a dictionary of form variables that were submitted in the request body via ``POST``. Don't forget to read about :ref:`internals_csrf`!
 
+``await request.post_body()`` - bytes
+    Returns the un-parsed body of a request submitted by ``POST`` - useful for things like incoming JSON data.
+
 .. _internals_multiparams:
 
 The MultiParams class

tests/test_internals_request.py

@@ -1,4 +1,5 @@
 from datasette.utils.asgi import Request
+import json
 import pytest
 
 
@@ -26,6 +27,34 @@ async def test_request_post_vars():
     assert {"foo": "bar", "baz": "1", "empty": ""} == await request.post_vars()
 
 
+@pytest.mark.asyncio
+async def test_request_post_body():
+    scope = {
+        "http_version": "1.1",
+        "method": "POST",
+        "path": "/",
+        "raw_path": b"/",
+        "query_string": b"",
+        "scheme": "http",
+        "type": "http",
+        "headers": [[b"content-type", b"application/json"]],
+    }
+
+    data = {"hello": "world"}
+
+    async def receive():
+        return {
+            "type": "http.request",
+            "body": json.dumps(data, indent=4).encode("utf-8"),
+            "more_body": False,
+        }
+
+    request = Request(scope, receive)
+    body = await request.post_body()
+    assert isinstance(body, bytes)
+    assert data == json.loads(body)
+
+
 def test_request_args():
     request = Request.fake("/foo?multi=1&multi=2&single=3")
     assert "1" == request.args.get("multi")