Streaming migration for 20.3 release (#1800)

* Compatibility and deprecations for Sanic 20.3 in preparation of the streaming branch.

* Add test for new API.

* isort tests

* More coverage

* json takes str, not bytes

Co-authored-by: L. Kärkkäinen <tronic@users.noreply.github.com>

sanic/request.py

@@ -56,6 +56,14 @@ class StreamBuffer:
         self._queue.task_done()
         return payload
 
+    async def __aiter__(self):
+        """Support `async for data in request.stream`"""
+        while True:
+            data = await self.read()
+            if not data:
+                break
+            yield data
+
     async def put(self, payload):
         await self._queue.put(payload)
 
@@ -128,14 +136,33 @@ class Request:
         )
 
     def body_init(self):
+        """.. deprecated:: 20.3"""
         self.body = []
 
     def body_push(self, data):
+        """.. deprecated:: 20.3"""
         self.body.append(data)
 
     def body_finish(self):
+        """.. deprecated:: 20.3"""
         self.body = b"".join(self.body)
 
+    async def receive_body(self):
+        """Receive request.body, if not already received.
+
+        Streaming handlers may call this to receive the full body.
+
+        This is added as a compatibility shim in Sanic 20.3 because future
+        versions of Sanic will make all requests streaming and will use this
+        function instead of the non-async body_init/push/finish functions.
+
+        Please make an issue if your code depends on the old functionality and
+        cannot be upgraded to the new API.
+        """
+        if not self.stream:
+            return
+        self.body = b"".join([data async for data in self.stream])
+
     @property
     def json(self):
         if self.parsed_json is None:

tests/test_request_stream.py

@@ -3,7 +3,7 @@ import pytest
 from sanic.blueprints import Blueprint
 from sanic.exceptions import HeaderExpectationFailed
 from sanic.request import StreamBuffer
-from sanic.response import stream, text
+from sanic.response import json, stream, text
 from sanic.views import CompositionView, HTTPMethodView
 from sanic.views import stream as stream_decorator
 
@@ -613,3 +613,43 @@ def test_request_stream(app):
     request, response = app.test_client.post("/bp_stream", data=data)
     assert response.status == 200
     assert response.text == data
+
+def test_streaming_new_api(app):
+    @app.post("/non-stream")
+    async def handler(request):
+        assert request.body == b"x"
+        await request.receive_body()  # This should do nothing
+        assert request.body == b"x"
+        return text("OK")
+
+    @app.post("/1", stream=True)
+    async def handler(request):
+        assert request.stream
+        assert not request.body
+        await request.receive_body()
+        return text(request.body.decode().upper())
+
+    @app.post("/2", stream=True)
+    async def handler(request):
+        ret = []
+        async for data in request.stream:
+            # We should have no b"" or None, just proper chunks
+            assert data
+            assert isinstance(data, bytes)
+            ret.append(data.decode("ASCII"))
+        return json(ret)
+
+    request, response = app.test_client.post("/non-stream", data="x")
+    assert response.status == 200
+
+    request, response = app.test_client.post("/1", data="TEST data")
+    assert request.body == b"TEST data"
+    assert response.status == 200
+    assert response.text == "TEST DATA"
+
+    request, response = app.test_client.post("/2", data=data)
+    assert response.status == 200
+    res = response.json
+    assert isinstance(res, list)
+    assert len(res) > 1
+    assert "".join(res) == data

tests/test_response.py

@@ -15,6 +15,7 @@ from aiofiles import os as async_os
 from sanic.response import (
     HTTPResponse,
     StreamingHTTPResponse,
+    empty,
     file,
     file_stream,
     json,
@@ -22,7 +23,6 @@ from sanic.response import (
     stream,
     text,
 )
-from sanic.response import empty
 from sanic.server import HttpProtocol
 from sanic.testing import HOST, PORT