From d3e99c9a357031d8f01ccc626aa307ba02f0154d Mon Sep 17 00:00:00 2001
From: Eli Uriegas <seemethere101@gmail.com>
Date: Sun, 25 Dec 2016 09:49:54 -0800
Subject: [PATCH] Add performant smart response handling

---
 sanic/server.py        | 27 +++++++++++++++++++----
 tests/test_response.py | 49 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 4 deletions(-)

diff --git a/sanic/server.py b/sanic/server.py
index 11756005..b5e27f5a 100644
--- a/sanic/server.py
+++ b/sanic/server.py
@@ -6,7 +6,9 @@ from signal import SIGINT, SIGTERM
 from time import time
 from httptools import HttpRequestParser
 from httptools.parser.errors import HttpParserError
+
 from .exceptions import ServerError
+from .response import json, text
 
 try:
     import uvloop as async_loop
@@ -147,12 +149,29 @@ class HttpProtocol(asyncio.Protocol):
     # -------------------------------------------- #
 
     def write_response(self, response):
-        try:
-            keep_alive = self.parser.should_keep_alive() \
-                            and not self.signal.stopped
+
+        def attempt_write(_response):
             self.transport.write(
-                response.output(
+                _response.output(
                     self.request.version, keep_alive, self.request_timeout))
+
+        try:
+            keep_alive = (self.parser.should_keep_alive()
+                          and not self.signal.stopped)
+
+            try:
+                # If we already have an HTTPResponse object this should be
+                # as fast as ever
+                attempt_write(response)
+            except AttributeError:
+                try:
+                    # A performant way to check if we have a list or dict
+                    # Both list and dict contain a `clear` function
+                    response.clear
+                    attempt_write(json(response))
+                except AttributeError:
+                    attempt_write(text(str(response)))
+
             if not keep_alive:
                 self.transport.close()
             else:
diff --git a/tests/test_response.py b/tests/test_response.py
index f35f10e9..6dd504f4 100644
--- a/tests/test_response.py
+++ b/tests/test_response.py
@@ -1,4 +1,7 @@
 from random import choice
+from json import loads as json_loads, JSONDecodeError
+
+import pytest
 
 from sanic import Sanic
 from sanic.response import HTTPResponse
@@ -16,3 +19,49 @@ def test_response_body_not_a_string():
 
     request, response = sanic_endpoint_test(app, uri='/hello')
     assert response.text == str(random_num)
+
+
+def test_json():
+    """Tests the smart handling of dicts for handlers"""
+    app = Sanic('test_json')
+
+    @app.route('/')
+    async def handler(request):
+        return {"test": True}
+
+    request, response = sanic_endpoint_test(app)
+
+    try:
+        results = json_loads(response.text)
+    except JSONDecodeError:
+        pytest.fail(
+            "Expected JSON response but got '{}'".format(response))
+
+    assert results.get('test') is True
+
+
+def test_text():
+    """Tests the smart handling of strings for handlers"""
+    app = Sanic('test_text')
+
+    @app.route('/')
+    async def handler(request):
+        return 'Hello'
+
+    request, response = sanic_endpoint_test(app)
+
+    assert response.text == 'Hello'
+
+
+def test_int():
+    """Tests the smart handling of ints for handlers"""
+    app = Sanic('test_int')
+    random_int = choice(range(0, 10000))
+
+    @app.route('/')
+    async def handler(request):
+        return random_int
+
+    request, response = sanic_endpoint_test(app)
+
+    assert response.text == str(random_int)