Use printf-style String Formatting for output

sanic/response.py

@@ -1,18 +1,18 @@
 import ujson
 
 STATUS_CODES = {
-    200: 'OK',
-    400: 'Bad Request',
-    401: 'Unauthorized',
-    402: 'Payment Required',
-    403: 'Forbidden',
-    404: 'Not Found',
-    405: 'Method Not Allowed',
-    500: 'Internal Server Error',
-    501: 'Not Implemented',
-    502: 'Bad Gateway',
-    503: 'Service Unavailable',
-    504: 'Gateway Timeout',
+    200: b'OK',
+    400: b'Bad Request',
+    401: b'Unauthorized',
+    402: b'Payment Required',
+    403: b'Forbidden',
+    404: b'Not Found',
+    405: b'Method Not Allowed',
+    500: b'Internal Server Error',
+    501: b'Not Implemented',
+    502: b'Bad Gateway',
+    503: b'Service Unavailable',
+    504: b'Gateway Timeout',
 }
 
 
@@ -33,24 +33,24 @@ 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
-        additional_headers = []
-        if keep_alive and not keep_alive_timeout is None:
-            additional_headers = [b'Keep-Alive: timeout=', str(keep_alive_timeout).encode(), b's\r\n']
+        timeout_header = b''
+        if keep_alive and keep_alive_timeout:
+            timeout_header = b'Keep-Alive: timeout=%d\r\n' % keep_alive_timeout
+
+        headers = b''
         if self.headers:
-            for name, value in self.headers.items():
-                additional_headers.append('{}: {}\r\n'.format(name, value).encode('utf-8'))
-
-        return b''.join([
-                            'HTTP/{} {} {}\r\n'.format(version, self.status,
-                                                       STATUS_CODES.get(self.status, 'FAIL')).encode(),
-                            b'Content-Type: ', self.content_type.encode(), b'\r\n',
-                            b'Content-Length: ', str(len(self.body)).encode(), b'\r\n',
-                            b'Connection: ', ('keep-alive' if keep_alive else 'close').encode(), b'\r\n',
-                        ] + additional_headers + [
-                            b'\r\n',
-                            self.body,
-                        ])
-
+            headers = b''.join(b'%b: %b\r\n' % (name.encode(), value.encode('utf-8')) for name, value in self.headers.items())
+        return b'HTTP/%b %d %b\r\nContent-Type: %b\r\nContent-Length: %d\r\nConnection: %b\r\n%b%b\r\n%b' % (
+            version.encode(),
+            self.status,
+            STATUS_CODES.get(self.status, b'FAIL'),
+            self.content_type.encode(),
+            len(self.body),
+            b'keep-alive' if keep_alive else b'close',
+            timeout_header,
+            headers,
+            self.body
+        )
 
 def json(body, status=200, headers=None):
     return HTTPResponse(ujson.dumps(body), headers=headers, status=status,