Merge pull request #473 from subyraman/explore-streams-v2

Add `stream` method for streaming content, add docs and examples

tests/test_response.py

@@ -1,8 +1,12 @@
+import asyncio
+import pytest
 from random import choice
 
 from sanic import Sanic
-from sanic.response import HTTPResponse
+from sanic.response import HTTPResponse, stream, StreamingHTTPResponse
+from sanic.testing import HOST, PORT
 
+from unittest.mock import MagicMock
 
 def test_response_body_not_a_string():
     """Test when a response body sent from the application is not a string"""
@@ -15,3 +19,78 @@ def test_response_body_not_a_string():
 
     request, response = app.test_client.get('/hello')
     assert response.text == str(random_num)
+
+
+async def sample_streaming_fn(response):
+    response.write('foo,')
+    await asyncio.sleep(.001)
+    response.write('bar')
+
+
+@pytest.fixture
+def streaming_app():
+    app = Sanic('streaming')
+
+    @app.route("/")
+    async def test(request):
+        return stream(sample_streaming_fn, content_type='text/csv')
+
+    return app
+
+
+def test_streaming_adds_correct_headers(streaming_app):
+    request, response = streaming_app.test_client.get('/')
+    assert response.headers['Transfer-Encoding'] == 'chunked'
+    assert response.headers['Content-Type'] == 'text/csv'
+
+
+def test_streaming_returns_correct_content(streaming_app):
+    request, response = streaming_app.test_client.get('/')
+    assert response.text == 'foo,bar'
+
+
+@pytest.mark.parametrize('status', [200, 201, 400, 401])
+def test_stream_response_status_returns_correct_headers(status):
+    response = StreamingHTTPResponse(sample_streaming_fn, status=status)
+    headers = response.get_headers()
+    assert b"HTTP/1.1 %s" % str(status).encode() in headers
+
+
+@pytest.mark.parametrize('keep_alive_timeout', [10, 20, 30])
+def test_stream_response_keep_alive_returns_correct_headers(
+        keep_alive_timeout):
+    response = StreamingHTTPResponse(sample_streaming_fn)
+    headers = response.get_headers(
+        keep_alive=True, keep_alive_timeout=keep_alive_timeout)
+
+    assert b"Keep-Alive: %s\r\n" % str(keep_alive_timeout).encode() in headers
+
+
+def test_stream_response_includes_chunked_header():
+    response = StreamingHTTPResponse(sample_streaming_fn)
+    headers = response.get_headers()
+    assert b"Transfer-Encoding: chunked\r\n" in headers
+
+
+def test_stream_response_writes_correct_content_to_transport(streaming_app):
+    response = StreamingHTTPResponse(sample_streaming_fn)
+    response.transport = MagicMock(asyncio.Transport)
+
+    @streaming_app.listener('after_server_start')
+    async def run_stream(app, loop):
+        await response.stream()
+        assert response.transport.write.call_args_list[1][0][0] == (
+            b'4\r\nfoo,\r\n'
+        )
+
+        assert response.transport.write.call_args_list[2][0][0] == (
+            b'3\r\nbar\r\n'
+        )
+
+        assert response.transport.write.call_args_list[3][0][0] == (
+            b'0\r\n\r\n'
+        )
+
+        app.stop()
+
+    streaming_app.run(host=HOST, port=PORT)