Add accept_encoding_property and tests.

1 files changed, 61 insertions, 0 deletions

diff --git a/src/webob/acceptparse.py b/src/webob/acceptparse.py
index 7733d27..db63a34 100644
--- a/src/webob/acceptparse.py
+++ b/src/webob/acceptparse.py
@@ -1241,6 +1241,67 @@ def create_accept_encoding_header(header_value):
         return AcceptEncodingInvalidHeader(header_value=header_value)
 
 
+def accept_encoding_property():
+    doc = """
+        Property representing the ``Accept-Encoding`` header.
+
+        (:rfc:`RFC 7231, section 5.3.4 <7231#section-5.3.4>`)
+
+        The header value in the request environ is parsed and a new object
+        representing the header is created every time we *get* the value of the
+        property. (*set* and *del* change the header value in the request
+        environ, and do not involve parsing.)
+    """
+
+    ENVIRON_KEY = 'HTTP_ACCEPT_ENCODING'
+
+    def fget(request):
+        """Get an object representing the header in the request."""
+        return create_accept_encoding_header(
+            header_value=request.environ.get(ENVIRON_KEY)
+        )
+
+    def fset(request, value):
+        """
+        Set the corresponding key in the request environ.
+
+        `value` can be:
+
+        * ``None``
+        * a ``str`` header value
+        * a ``dict``, with content-coding, ``identity`` or ``*`` ``str``\ s as
+          keys, and qvalue ``float``\ s as values
+        * a ``tuple`` or ``list``, where each item is either a header element
+          ``str``, or a (content-coding/``identity``/``*``, qvalue) ``tuple``
+          or ``list``
+        * an :class:`AcceptEncodingValidHeader`,
+          :class:`AcceptEncodingNoHeader`, or
+          :class:`AcceptEncodingInvalidHeader` instance
+        * object of any other type that returns a value for ``__str__``
+        """
+        if value is None or isinstance(value, AcceptEncodingNoHeader):
+            fdel(request=request)
+        else:
+            if isinstance(
+                value, (AcceptEncodingValidHeader, AcceptEncodingInvalidHeader)
+            ):
+                header_value = value.header_value
+            else:
+                header_value = AcceptEncoding._python_value_to_header_str(
+                    value=value,
+                )
+            request.environ[ENVIRON_KEY] = header_value
+
+    def fdel(request):
+        """Delete the corresponding key from the request environ."""
+        try:
+            del request.environ[ENVIRON_KEY]
+        except KeyError:
+            pass
+
+    return property(fget, fset, fdel, textwrap.dedent(doc))
+
+
 class AcceptLanguage(object):
     """
     Represent an ``Accept-Language`` header.