1 files changed, 70 insertions, 0 deletions
diff --git a/netlib/http/message.py b/netlib/http/message.py
index da9681a0..db4054b1 100644
--- a/netlib/http/message.py
+++ b/netlib/http/message.py
@@ -4,6 +4,7 @@ import warnings
 
 import six
 
+from ..multidict import MultiDict
 from .headers import Headers
 from .. import encoding, utils
 
@@ -235,3 +236,72 @@ class decoded(object):
     def __exit__(self, type, value, tb):
         if self.ce:
             self.message.encode(self.ce)
+
+
+class MultiDictView(MultiDict):
+    """
+    Some parts in HTTP (Cookies, URL query strings, ...) require a specific data structure: A MultiDict.
+    It behaves mostly like an ordered dict but it can have several values for the same key.
+
+    The MultiDictView provides a MultiDict *view* on an :py:class:`Request` or :py:class:`Response`.
+    That is, it represents a part of the request as a MultiDict, but doesn't contain state/data themselves.
+
+    For example, ``request.cookies`` provides a view on the ``Cookie: ...`` header.
+    Any change to ``request.cookies`` will also modify the ``Cookie`` header.
+    Any change to the ``Cookie`` header will also modify ``request.cookies``.
+
+    Example:
+
+    .. code-block:: python
+
+        # Cookies are represented as a MultiDict.
+        >>> request.cookies
+        MultiDictView[("name", "value"), ("a", "false"), ("a", "42")]
+
+        # MultiDicts mostly behave like a normal dict.
+        >>> request.cookies["name"]
+        "value"
+
+        # If there is more than one value, only the first value is returned.
+        >>> request.cookies["a"]
+        "false"
+
+        # `.get_all(key)` returns a list of all values.
+        >>> request.cookies.get_all("a")
+        ["false", "42"]
+
+        # Changes to the headers are immediately reflected in the cookies.
+        >>> request.cookies
+        MultiDictView[("name", "value"), ...]
+        >>> del request.headers["Cookie"]
+        >>> request.cookies
+        MultiDictView[]  # empty now
+    """
+
+    def __init__(self, attr, message):
+        if False:  # pragma: no cover
+            # We do not want to call the parent constructor here as that
+            # would cause an unnecessary parse/unparse pass.
+            # This is here to silence linters. Message
+            super(MultiDictView, self).__init__(None)
+        self._attr = attr
+        self._message = message  # type: Message
+
+    @staticmethod
+    def _kconv(key):
+        # All request-attributes are case-sensitive.
+        return key
+
+    @staticmethod
+    def _reduce_values(values):
+        # We just return the first element if
+        # multiple elements exist with the same key.
+        return values[0]
+
+    @property
+    def fields(self):
+        return getattr(self._message, "_" + self._attr)
+
+    @fields.setter
+    def fields(self, value):
+        setattr(self._message, self._attr, value)