Allow Headers.add to get a list of parameters on *args

tests/test_datastructures.py

@@ -631,6 +631,9 @@ def test_basic_interface(self):
         headers.add('x', 'y', z='"')
         assert headers['x'] == r'y; z="\""'
 
+        headers.add('multi', 'yes', ('a', '1',), ('b', '2'), c='3')
+        assert headers['multi'] == 'yes; a=1; b=2; c=3'
+
     def test_defaults_and_conversion(self):
         # defaults
         headers = self.storage_class([

werkzeug/datastructures.py

@@ -889,9 +889,20 @@ def popitemlist(self):
         return key, [x.value for x in buckets]
 
 
-def _options_header_vkw(value, kw):
-    return dump_options_header(value, dict((k.replace('_', '-'), v)
-                                           for k, v in kw.items()))
+def _options_header_vkw(value, args, kwargs):
+    if args:
+        value = dump_options_header(
+            value,
+            ((k.replace('_', '-'), v) for k, v in args)
+        )
+
+    if kwargs:
+        value = dump_options_header(
+            value,
+            dict((k.replace('_', '-'), v) for k, v in iteritems(kwargs))
+        )
+
+    return value
 
 
 def _unicodify_header_value(value):
@@ -1140,7 +1151,7 @@ def __iter__(self):
     def __len__(self):
         return len(self._list)
 
-    def add(self, _key, _value, **kw):
+    def add(self, _key, _value, *args, **kwargs):
         """Add a new header tuple to the list.
 
         Keyword arguments can specify additional parameters for the header
@@ -1153,11 +1164,23 @@ def add(self, _key, _value, **kw):
         The keyword argument dumping uses :func:`dump_options_header`
         behind the scenes.
 
+        In some cases the order of the additional parameters is important.
+        For those cases, a list of ``(key, value)`` tuples can be passed in
+        ``*args``::
+
+            d.add(
+                'Content-Disposition', 'attachment',
+                ('filename', 'foo.png'), ('filename*', "UTF-8''fo%C3%B6.png")
+            )
+
+        .. versionadded:: 0.13.0
+            Key/value tuples as positional arguments are supported to ensure
+            the order of parameters.
+
         .. versionadded:: 0.4.1
             keyword arguments were added for :mod:`wsgiref` compatibility.
         """
-        if kw:
-            _value = _options_header_vkw(_value, kw)
+        _value = _options_header_vkw(_value, args, kwargs)
         _value = _unicodify_header_value(_value)
         self._validate_value(_value)
         self._list.append((_key, _value))
@@ -1181,23 +1204,22 @@ def clear(self):
         """Clears all headers."""
         del self._list[:]
 
-    def set(self, _key, _value, **kw):
+    def set(self, _key, _value, *args, **kwargs):
         """Remove all header tuples for `key` and add a new one.  The newly
         added key either appears at the end of the list if there was no
         entry or replaces the first one.
 
-        Keyword arguments can specify additional parameters for the header
-        value, with underscores converted to dashes.  See :meth:`add` for
-        more information.
+        Positional and keyword arguments can specify additional parameters for
+        the header value, with underscores converted to dashes.  See
+        :meth:`add` for more information.
 
         .. versionchanged:: 0.6.1
            :meth:`set` now accepts the same arguments as :meth:`add`.
 
         :param key: The key to be inserted.
         :param value: The value to be inserted.
         """
-        if kw:
-            _value = _options_header_vkw(_value, kw)
+        _value = _options_header_vkw(_value, args, kwargs)
         _value = _unicodify_header_value(_value)
         self._validate_value(_value)
         if not self._list:

werkzeug/http.py

@@ -17,6 +17,7 @@
     :license: BSD, see LICENSE for more details.
 """
 import re
+from collections import Mapping
 from time import time, gmtime
 try:
     from email.utils import parsedate_tz
@@ -207,12 +208,14 @@ def dump_options_header(header, options):
     """The reverse function to :func:`parse_options_header`.
 
     :param header: the header to dump
-    :param options: a dict of options to append.
+    :param options: a dict of options to append. Or pass a sequence of
+        ``(key, value)`` pairs to ensure the order of the keys.
     """
     segments = []
     if header is not None:
         segments.append(header)
-    for key, value in iteritems(options):
+    iter_func = iteritems if isinstance(options, Mapping) else iter
+    for key, value in iter_func(options):
         if value is None:
             segments.append(key)
         else: