Lazy cookie creation

sanic/cookies.py

@@ -0,0 +1,123 @@
+from datetime import datetime
+import re
+import string
+
+# ------------------------------------------------------------ #
+#  SimpleCookie
+# ------------------------------------------------------------ #
+
+# Straight up copied this section of dark magic from SimpleCookie
+
+_LegalChars = string.ascii_letters + string.digits + "!#$%&'*+-.^_`|~:"
+_UnescapedChars = _LegalChars + ' ()/<=>?@[]{}'
+
+_Translator = {n: '\\%03o' % n
+               for n in set(range(256)) - set(map(ord, _UnescapedChars))}
+_Translator.update({
+    ord('"'): '\\"',
+    ord('\\'): '\\\\',
+})
+
+def _quote(str):
+    r"""Quote a string for use in a cookie header.
+    If the string does not need to be double-quoted, then just return the
+    string.  Otherwise, surround the string in doublequotes and quote
+    (with a \) special characters.
+    """
+    if str is None or _is_legal_key(str):
+        return str
+    else:
+        return '"' + str.translate(_Translator) + '"'
+
+_is_legal_key = re.compile('[%s]+' % re.escape(_LegalChars)).fullmatch
+
+# ------------------------------------------------------------ #
+#  Custom SimpleCookie
+# ------------------------------------------------------------ #
+
+class CookieJar(dict):
+    """
+    CookieJar dynamically writes headers as cookies are added and removed
+    It gets around the limitation of one header per name by using the
+    MultiHeader class to provide a unique key that encodes to Set-Cookie
+    """
+    def __init__(self, headers):
+        super().__init__()
+        self.headers = headers
+        self.cookie_headers = {}
+    def __setitem__(self, key, value):
+        # If this cookie doesn't exist, add it to the header keys
+        cookie_header = self.cookie_headers.get(key)
+        if not cookie_header:
+            cookie = Cookie(key, value)
+            cookie_header = MultiHeader("Set-Cookie")
+            self.cookie_headers[key] = cookie_header
+            self.headers[cookie_header] = cookie
+            return super().__setitem__(key, cookie)
+        else:
+            self[key].value = value
+
+    def __delitem__(self, key):
+        del self.cookie_headers[key]
+        return super().__delitem__(key)
+
+class Cookie(dict):
+    """
+    This is a stripped down version of Morsel from SimpleCookie #gottagofast
+    """
+    _keys = {
+        "expires"  : "expires",
+        "path"     : "Path",
+        "comment"  : "Comment",
+        "domain"   : "Domain",
+        "max-age"  : "Max-Age",
+        "secure"   : "Secure",
+        "httponly" : "HttpOnly",
+        "version"  : "Version",
+    }
+    _flags = {'secure', 'httponly'}
+
+    def __init__(self, key, value):
+        if key in self._keys:
+            raise KeyError("Cookie name is a reserved word")
+        if not _is_legal_key(key):
+            raise KeyError("Cookie key contains illegal characters")
+        self.key = key
+        self.value = value
+        super().__init__()
+
+    def __setitem__(self, key, value):
+        if not key in self._keys:
+            raise KeyError("Unknown cookie property")
+        return super().__setitem__(key, value)
+
+    def encode(self, encoding):
+        output = ['%s=%s' % (self.key, _quote(self.value))]
+        for key, value in self.items():
+            if key == 'max-age' and isinstance(value, int):
+                output.append('%s=%d' % (self._keys[key], value))
+            elif key == 'expires' and isinstance(value, datetime):
+                output.append('%s=%s' % (
+                    self._keys[key],
+                    value.strftime("%a, %d-%b-%Y %T GMT")
+                ))
+            elif key in self._flags:
+                output.append(self._keys[key])
+            else:
+                output.append('%s=%s' % (self._keys[key], value))
+
+        return "; ".join(output).encode(encoding)
+
+# ------------------------------------------------------------ #
+#  Header Trickery
+# ------------------------------------------------------------ #
+
+class MultiHeader:
+    """
+    Allows us to set a header within response that has a unique key,
+    but may contain duplicate header names
+    """
+    def __init__(self, name):
+        self.name = name
+    def encode(self):
+        return self.name.encode()

sanic/response.py

@@ -1,6 +1,5 @@
 from aiofiles import open as open_async
-from datetime import datetime
-from http.cookies import SimpleCookie
+from .cookies import CookieJar
 from mimetypes import guess_type
 from os import path
 from ujson import dumps as json_dumps
@@ -101,12 +100,6 @@ class HTTPResponse:
                 b'%b: %b\r\n' % (name.encode(), value.encode('utf-8'))
                 for name, value in self.headers.items()
             )
-        if self._cookies:
-            for cookie in self._cookies.values():
-                if type(cookie['expires']) is datetime:
-                    cookie['expires'] = \
-                        cookie['expires'].strftime("%a, %d-%b-%Y %T GMT")
-            headers += (str(self._cookies) + "\r\n").encode('utf-8')
 
         # Try to pull from the common codes first
         # Speeds up response rate 6% over pulling from all
@@ -134,7 +127,7 @@ class HTTPResponse:
     @property
     def cookies(self):
         if self._cookies is None:
-            self._cookies = SimpleCookie()
+            self._cookies = CookieJar(self.headers)
         return self._cookies