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# $Header: /var/local/cvsroot/4Suite/Ft/Server/Server/Http/HeaderDict.py,v 1.6 2005/03/06 03:53:55 mbrown Exp $
"""
MIME message header storage for HTTP
Copyright 2005 Fourthought, Inc. (USA).
Detailed license and copyright information: http://4suite.org/COPYRIGHT
Project home, documentation, distributions: http://4suite.org/
"""
from __future__ import generators
class HeaderDict(dict):
"""
A dictionary-like object for storing MIME-like message headers.
Headers are stored in the object via regular dictionary interfaces.
They are retrieved via str(), repr() or self.terse(), which returns
a standard dict with duplicate headers merged into a comma-separated
list of values (even when it is not OK to do so).
The reason this class is needed is because the dictionary interface of
the Message class of the rfc822 and mimetools modules allows each new
header to overwrite a previously-stored header with the same key. Our
HeaderDict class stores its header values as lists, so no data is lost.
Its keys are accessed case-insensitively and are always written out
in a normalized format where usually only the first letter of each
hyphen-separated word is capitalized. (Content-MD5, ETag, TE, and
WWW-Authenticate are exceptions to this rule). The str(obj)
representation prints the headers in a convenient format suitable for
printing in a MIME-like message.
"""
# exceptions to the automatic camel-capping
forceCaps = { 'content-md5': 'Content-MD5',
'etag': 'ETag',
'te': 'TE',
'www-authenticate': 'WWW-Authenticate'
}
# camel-cap a hyphenated string
def _camelCap(self, s, checkForceCaps=False):
if len(s) == 0:
return ''
if checkForceCaps:
if s.lower() in forceCaps.keys():
return forceCaps[s.lower()]
return '-'.join(map(lambda s: s[:1].upper() + s.lower()[1:], s.split('-')))
def __init__(self, obj=None):
if obj is None:
return super(HeaderDict, self).__init__()
elif isinstance(obj, (tuple, list, str, unicode)):
for k, v in obj:
self.__setitem__(k, v)
else:
# will raise same TypeError as dict, if not iterable
for k in obj:
self.__setitem__(k, obj[k])
return
# case-insensitive lookup
def __getitem__(self, key):
return super(HeaderDict, self).__getitem__(key.lower())
# case-insensitive 'key in dict' lookup
def __contains__(self, key):
return super(HeaderDict, self).__contains__(key.lower())
# case-insensitive 'for key in dict' iteration
def __iter__(self):
return iter(self.keys())
# case-insensitive iterators
iterkeys = __iter__
def iteritems(self):
for key in self.iterkeys():
yield key, self.__getitem__(key)
# case-insensitive storage; appends to a list
def __setitem__(self, key, value):
if self.has_key(key):
l = super(HeaderDict, self).__getitem__(key.lower())
l.append(value)
return super(HeaderDict, self).__setitem__(key.lower(), l)
else:
return super(HeaderDict, self).__setitem__(key.lower(), [value])
# case-insensitive deletion: removes entire list
def __delitem__(self, key):
return super(HeaderDict, self).__delitem__(key.lower())
# retrieve a value or default if no such key
def get(self, key, default=None):
if self.has_key(key):
return self.__getitem__(key)
else:
return default
# case-insensitive key lookup
def has_key(self, key):
return super(HeaderDict, self).has_key(key.lower())
# normalize key names
def keys(self):
return [self._camelCap(key, False) for key in super(HeaderDict, self).keys()]
# return a terse dictionary (duplicate headers in one comma-separated string)
# this is for compatibility with functions want to read the header values as
# a single string rather than as a python list of strings
def terse(self):
newdict = {}
for key in self.keys():
newdict[key] = ', '.join(self.__getitem__(key))
return newdict
# append another dict or HeaderDict
def update(self, dict_):
if isinstance(dict_, self.__class__):
for key in dict_:
for val in dict_[key]:
self.__setitem__(key, val)
elif isinstance(dict_, dict):
for key in dict_:
self.__setitem__(key, dict_[key])
else:
raise TypeError("HeaderDict.update() called with a non-dictionary argument")
return
# string representations
def __repr__(self):
# dictionary syntax
return '{%s}' % ', '.join([("%s: %s" % (repr(key), repr(self.__getitem__(key.lower())))) for key in self.keys()])
def __str__(self):
# a series of 'Hyphenated-Header: value' CRLF-terminated lines, or empty string
rv = ''
if len(self.keys()):
for key in self.keys():
val = self.__getitem__(key.lower())
rv += ''.join(['%s: %s\r\n' % (key, v) for v in val])
return rv
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