William Grant
61 lines
1.8 KiB
Python
61 lines
1.8 KiB
Python
# This software is provided 'as-is', without any express or implied
|
|
# warranty. In no event will the author be held liable for any damages
|
|
# arising from the use of this software.
|
|
#
|
|
# Permission is granted to anyone to use this software for any purpose,
|
|
# including commercial applications, and to alter it and redistribute it
|
|
# freely, subject to the following restrictions:
|
|
#
|
|
# 1. The origin of this software must not be misrepresented; you must not
|
|
# claim that you wrote the original software. If you use this software
|
|
# in a product, an acknowledgment in the product documentation would be
|
|
# appreciated but is not required.
|
|
# 2. Altered source versions must be plainly marked as such, and must not be
|
|
# misrepresented as being the original software.
|
|
# 3. This notice may not be removed or altered from any source distribution.
|
|
#
|
|
# Copyright (c) 2011 William Grant <me@williamgrant.id.au>
|
|
|
|
__all__ = [
|
|
'DuplicateTag',
|
|
'InvalidTagSpec',
|
|
'InvalidTagValueList',
|
|
'parse_tag_value',
|
|
]
|
|
|
|
|
|
class InvalidTagValueList(Exception):
|
|
pass
|
|
|
|
|
|
class DuplicateTag(InvalidTagValueList):
|
|
pass
|
|
|
|
|
|
class InvalidTagSpec(InvalidTagValueList):
|
|
pass
|
|
|
|
|
|
def parse_tag_value(tag_list):
|
|
"""Parse a DKIM Tag=Value list.
|
|
|
|
Interprets the syntax specified by RFC4871 section 3.2.
|
|
Assumes that folding whitespace is already unfolded.
|
|
|
|
@param tag_list: A string containing a DKIM Tag=Value list.
|
|
"""
|
|
tags = {}
|
|
tag_specs = tag_list.split(';')
|
|
# Trailing semicolons are valid.
|
|
if not tag_specs[-1]:
|
|
tag_specs.pop()
|
|
for tag_spec in tag_specs:
|
|
try:
|
|
key, value = tag_spec.split('=', 1)
|
|
except ValueError:
|
|
raise InvalidTagSpec(tag_spec)
|
|
if key.strip() in tags:
|
|
raise DuplicateTag(key.strip())
|
|
tags[key.strip()] = value.strip()
|
|
return tags
|