await request.json() method, closes #2767

datasette/utils/asgi.py

@@ -155,6 +155,10 @@ class Request:
         body = await self.post_body()
         return dict(parse_qsl(body.decode("utf-8"), keep_blank_values=True))
 
+    async def json(self):
+        body = await self.post_body()
+        return json.loads(body)
+
     async def form(
         self,
         files: bool = False,

datasette/views/database.py

@@ -1093,9 +1093,8 @@ class TableCreateView(BaseView):
         ):
             return _error(["Permission denied"], 403)
 
-        body = await request.post_body()
         try:
-            data = json.loads(body)
+            data = await request.json()
         except json.JSONDecodeError as e:
             return _error(["Invalid JSON: {}".format(e)])
 

datasette/views/row.py

@@ -418,9 +418,8 @@ class RowUpdateView(BaseView):
         if not ok:
             return resolved
 
-        body = await request.post_body()
         try:
-            data = json.loads(body)
+            data = await request.json()
         except json.JSONDecodeError as e:
             return _error(["Invalid JSON: {}".format(e)])
 

datasette/views/table.py

@@ -673,9 +673,8 @@ class TableInsertView(BaseView):
         if not request.headers.get("content-type").startswith("application/json"):
             # TODO: handle form-encoded data
             return _errors(["Invalid content-type, must be application/json"])
-        body = await request.post_body()
         try:
-            data = json.loads(body)
+            data = await request.json()
         except json.JSONDecodeError as e:
             return _errors(["Invalid JSON: {}".format(e)])
         if not isinstance(data, dict):
@@ -974,7 +973,7 @@ class TableSetColumnTypeView(BaseView):
             return _error(["Invalid content-type, must be application/json"], 400)
 
         try:
-            data = json.loads(await request.post_body())
+            data = await request.json()
         except json.JSONDecodeError as e:
             return _error(["Invalid JSON: {}".format(e)], 400)
 
@@ -1091,7 +1090,7 @@ class TableDropView(BaseView):
             return _error(["Database is immutable"], 403)
         confirm = False
         try:
-            data = json.loads(await request.post_body())
+            data = await request.json()
             confirm = data.get("confirm")
         except json.JSONDecodeError:
             pass

docs/internals.rst

@@ -106,6 +106,9 @@ The object also has the following awaitable methods:
 ``await request.post_vars()`` - dictionary
     Returns a dictionary of form variables that were submitted in the request body via ``POST`` using ``application/x-www-form-urlencoded`` encoding. For multipart forms or file uploads, use ``request.form()`` instead.
 
+``await request.json()`` - Any
+    Returns the parsed JSON body of a request submitted by ``POST``.
+
 ``await request.post_body()`` - bytes
     Returns the un-parsed body of a request submitted by ``POST`` - useful for things like incoming JSON data.
 

tests/test_internals_request.py

@@ -55,6 +55,57 @@ async def test_request_post_body():
     assert data == json.loads(body)
 
 
+@pytest.mark.asyncio
+async def test_request_json():
+    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", "items": [1, 2, 3]}
+
+    async def receive():
+        return {
+            "type": "http.request",
+            "body": json.dumps(data).encode("utf-8"),
+            "more_body": False,
+        }
+
+    request = Request(scope, receive)
+    assert data == await request.json()
+
+
+@pytest.mark.asyncio
+async def test_request_json_invalid():
+    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"]],
+    }
+
+    async def receive():
+        return {
+            "type": "http.request",
+            "body": b"this is not JSON",
+            "more_body": False,
+        }
+
+    request = Request(scope, receive)
+    with pytest.raises(json.JSONDecodeError):
+        await request.json()
+
+
 def test_request_args():
     request = Request.fake("/foo?multi=1&multi=2&single=3")
     assert "1" == request.args.get("multi")