From ca02ed3b9fee507023a578385c0dd27487ed7ad5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kyle=20Bl=C3=B6m?= <kylejbloom@gmail.com>
Date: Sat, 28 Jan 2017 11:18:52 -0800
Subject: [PATCH] Changed output to use a default_header dictionary and a
 ChainMap to unnecessary conditionals and simplified range parsing logic

---
 sanic/response.py    | 82 +++++++++++++++++---------------------------
 sanic/static.py      |  2 +-
 tests/test_static.py |  2 +-
 3 files changed, 34 insertions(+), 52 deletions(-)

diff --git a/sanic/response.py b/sanic/response.py
index b8ea5ee8..287eec26 100644
--- a/sanic/response.py
+++ b/sanic/response.py
@@ -1,6 +1,7 @@
 from aiofiles import open as open_async
 from mimetypes import guess_type
 from os import path
+from collections import ChainMap
 
 from ujson import dumps as json_dumps
 
@@ -97,26 +98,24 @@ class HTTPResponse:
     def output(self, version="1.1", keep_alive=False, keep_alive_timeout=None):
         # This is all returned in a kind-of funky way
         # We tried to make this as fast as possible in pure python
-        if keep_alive and keep_alive_timeout:
-            if 'Keep-Alive' not in self.headers:
-                self.headers['Keep-Alive'] = keep_alive_timeout
-        if 'Connection' not in self.headers:
-            if keep_alive:
-                self.headers['Connection'] = 'keep-alive'
-            else:
-                self.headers['Connection'] = 'close'
-        if 'Content-Length' not in self.headers:
-            self.headers['Content-Length'] = len(self.body)
-        if 'Content-Type' not in self.headers:
-            self.headers['Content-Type'] = self.content_type
+        default_header = dict()
+        if keep_alive:
+            if keep_alive_timeout:
+                default_header['Keep-Alive'] = keep_alive_timeout
+            default_header['Connection'] = 'keep-alive'
+        else:
+            default_header['Connection'] = 'close'
+        default_header['Content-Length'] = len(self.body)
+        default_header['Content-Type'] = self.content_type
         headers = b''
-        if self.headers:
-            for name, value in self.headers.items():
-                try:
-                    headers += (b'%b: %b\r\n' % (
+        for name, value in ChainMap(self.headers, default_header).items():
+            try:
+                headers += (
+                    b'%b: %b\r\n' % (
                         name.encode(), value.encode('utf-8')))
-                except AttributeError:
-                    headers += (b'%b: %b\r\n' % (
+            except AttributeError:
+                headers += (
+                    b'%b: %b\r\n' % (
                         str(name).encode(), str(value).encode('utf-8')))
         # Try to pull from the common codes first
         # Speeds up response rate 6% over pulling from all
@@ -148,46 +147,29 @@ class ContentRangeHandler:
     __slots__ = ('start', 'end', 'size', 'total', 'headers')
 
     def __init__(self, request, stats):
-        self.start = self.size = 0
+        self.size = self.start = 0
         self.end = None
         self.headers = dict()
         self.total = stats.st_size
         _range = request.headers.get('Range')
-        if _range:
-            self.start, self.end = ContentRangeHandler.parse_range(_range)
-            if self.start is not None and self.end is not None:
-                self.size = self.end - self.start
-            elif self.end is not None:
-                self.size = self.end
-            elif self.start is not None:
-                self.size = self.total - self.start
-            else:
-                self.size = self.total
-            self.headers['Content-Range'] = "bytes %s-%s/%s" % (
-                self.start, self.end, self.total)
-        else:
-            self.size = self.total
-
-    def __bool__(self):
-        return self.size > 0
-
-    @staticmethod
-    def parse_range(range_header):
-        unit, _, value = tuple(map(str.strip, range_header.partition('=')))
+        if _range is None:
+            return
+        unit, _, value = tuple(map(str.strip, _range.partition('=')))
         if unit != 'bytes':
-            return None
+            return
         start_b, _, end_b = tuple(map(str.strip, value.partition('-')))
         try:
-            start = int(start_b) if start_b.strip() else None
-            end = int(end_b) if end_b.strip() else None
+            self.start = int(start_b) if start_b else 0
+            self.end = int(end_b) if end_b else 0
         except ValueError:
-            return None
-        if end is not None:
-            if start is None:
-                if end != 0:
-                    start = -end
-                    end = None
-        return start, end
+            self.start = self.end = 0
+            return
+        self.size = self.end - self.start
+        self.headers['Content-Range'] = "bytes %s-%s/%s" % (
+            self.start, self.end, self.total)
+
+    def __bool__(self):
+        return self.size != 0
 
 
 def json(body, status=200, headers=None, **kwargs):
diff --git a/sanic/static.py b/sanic/static.py
index a3df5918..e0255334 100644
--- a/sanic/static.py
+++ b/sanic/static.py
@@ -74,7 +74,7 @@ def register(app, uri, file_or_directory, pattern,
                     if _range.start >= _range.total or _range.end == 0:
                         raise ContentRangeError('Content-Range malformed',
                                                 _range)
-                    if _range.start == 0 and _range.size == _range.total:
+                    if _range.start == 0 and _range.size == 0:
                         _range = None
                     else:
                         headers['Content-Length'] = str(_range.size)
diff --git a/tests/test_static.py b/tests/test_static.py
index 5f9d9e09..601b0deb 100644
--- a/tests/test_static.py
+++ b/tests/test_static.py
@@ -74,7 +74,7 @@ def test_static_head_request(static_file_path, static_file_content):
     assert int(response.headers['Content-Length']) == len(static_file_content)
 
 
-def test_static_content_range(static_file_path, static_file_content):
+def test_static_content_range_correct(static_file_path, static_file_content):
     app = Sanic('test_static')
     app.static('/testing.file', static_file_path, use_content_range=True)