Add new utilities from werkzeug

requests/utils.py

@@ -12,9 +12,103 @@ that are also useful for external consumption.
 import cgi
 import codecs
 import cookielib
+import os
+import random
 import re
 import zlib
 
+from urllib2 import parse_http_list as _parse_list_header
+
+
+# From mitsuhiko/werkzeug (used with permission).
+def parse_list_header(value):
+    """Parse lists as described by RFC 2068 Section 2.
+
+    In particular, parse comma-separated lists where the elements of
+    the list may include quoted-strings.  A quoted-string could
+    contain a comma.  A non-quoted string could have quotes in the
+    middle.  Quotes are removed automatically after parsing.
+
+    It basically works like :func:`parse_set_header` just that items
+    may appear multiple times and case sensitivity is preserved.
+
+    The return value is a standard :class:`list`:
+
+    >>> parse_list_header('token, "quoted value"')
+    ['token', 'quoted value']
+
+    To create a header from the :class:`list` again, use the
+    :func:`dump_header` function.
+
+    :param value: a string with a list header.
+    :return: :class:`list`
+    """
+    result = []
+    for item in _parse_list_header(value):
+        if item[:1] == item[-1:] == '"':
+            item = unquote_header_value(item[1:-1])
+        result.append(item)
+    return result
+
+
+# From mitsuhiko/werkzeug (used with permission).
+def parse_dict_header(value):
+    """Parse lists of key, value pairs as described by RFC 2068 Section 2 and
+    convert them into a python dict:
+
+    >>> d = parse_dict_header('foo="is a fish", bar="as well"')
+    >>> type(d) is dict
+    True
+    >>> sorted(d.items())
+    [('bar', 'as well'), ('foo', 'is a fish')]
+
+    If there is no value for a key it will be `None`:
+
+    >>> parse_dict_header('key_without_value')
+    {'key_without_value': None}
+
+    To create a header from the :class:`dict` again, use the
+    :func:`dump_header` function.
+
+    :param value: a string with a dict header.
+    :return: :class:`dict`
+    """
+    result = {}
+    for item in _parse_list_header(value):
+        if '=' not in item:
+            result[item] = None
+            continue
+        name, value = item.split('=', 1)
+        if value[:1] == value[-1:] == '"':
+            value = unquote_header_value(value[1:-1])
+        result[name] = value
+    return result
+
+
+# From mitsuhiko/werkzeug (used with permission).
+def unquote_header_value(value, is_filename=False):
+    r"""Unquotes a header value.  (Reversal of :func:`quote_header_value`).
+    This does not use the real unquoting but what browsers are actually
+    using for quoting.
+
+    :param value: the header value to unquote.
+    """
+    if value and value[0] == value[-1] == '"':
+        # this is not the real unquoting, but fixing this so that the
+        # RFC is met will result in bugs with internet explorer and
+        # probably some other browsers as well.  IE for example is
+        # uploading files with "C:\foo\bar.txt" as filename
+        value = value[1:-1]
+
+        # if this is a filename and the starting characters look like
+        # a UNC path, then just return the value without quotes.  Using the
+        # replace sequence below on a UNC path has the effect of turning
+        # the leading double slash into a single slash and then
+        # _fix_ie_filename() doesn't work correctly.  See #458.
+        if not is_filename or value[:2] != '\\\\':
+            return value.replace('\\\\', '\\').replace('\\"', '"')
+    return value
+
 
 def header_expand(headers):
     """Returns an HTTP Header value string from a dictionary.
@@ -63,6 +157,21 @@ def header_expand(headers):
 
 
 
+def randombytes(n):
+    """Return n random bytes."""
+    # Use /dev/urandom if it is available.  Fall back to random module
+    # if not.  It might be worthwhile to extend this function to use
+    # other platform-specific mechanisms for getting random bytes.
+    if os.path.exists("/dev/urandom"):
+        f = open("/dev/urandom")
+        s = f.read(n)
+        f.close()
+        return s
+    else:
+        L = [chr(random.randrange(0, 256)) for i in range(n)]
+        return "".join(L)
+
+
 def dict_from_cookiejar(cj):
     """Returns a key/value dictionary from a CookieJar.