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590 lines
20 KiB
590 lines
20 KiB
6 years ago
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"""Representing and manipulating email headers via custom objects.
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This module provides an implementation of the HeaderRegistry API.
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The implementation is designed to flexibly follow RFC5322 rules.
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Eventually HeaderRegistry will be a public API, but it isn't yet,
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and will probably change some before that happens.
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"""
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from types import MappingProxyType
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from email import utils
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from email import errors
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from email import _header_value_parser as parser
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class Address:
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def __init__(self, display_name='', username='', domain='', addr_spec=None):
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"""Create an object representing a full email address.
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An address can have a 'display_name', a 'username', and a 'domain'. In
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addition to specifying the username and domain separately, they may be
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specified together by using the addr_spec keyword *instead of* the
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username and domain keywords. If an addr_spec string is specified it
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must be properly quoted according to RFC 5322 rules; an error will be
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raised if it is not.
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An Address object has display_name, username, domain, and addr_spec
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attributes, all of which are read-only. The addr_spec and the string
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value of the object are both quoted according to RFC5322 rules, but
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without any Content Transfer Encoding.
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"""
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# This clause with its potential 'raise' may only happen when an
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# application program creates an Address object using an addr_spec
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# keyword. The email library code itself must always supply username
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# and domain.
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if addr_spec is not None:
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if username or domain:
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raise TypeError("addrspec specified when username and/or "
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"domain also specified")
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a_s, rest = parser.get_addr_spec(addr_spec)
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if rest:
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raise ValueError("Invalid addr_spec; only '{}' "
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"could be parsed from '{}'".format(
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a_s, addr_spec))
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if a_s.all_defects:
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raise a_s.all_defects[0]
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username = a_s.local_part
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domain = a_s.domain
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self._display_name = display_name
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self._username = username
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self._domain = domain
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@property
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def display_name(self):
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return self._display_name
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@property
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def username(self):
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return self._username
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@property
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def domain(self):
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return self._domain
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@property
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def addr_spec(self):
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"""The addr_spec (username@domain) portion of the address, quoted
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according to RFC 5322 rules, but with no Content Transfer Encoding.
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"""
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nameset = set(self.username)
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if len(nameset) > len(nameset-parser.DOT_ATOM_ENDS):
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lp = parser.quote_string(self.username)
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else:
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lp = self.username
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if self.domain:
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return lp + '@' + self.domain
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if not lp:
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return '<>'
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return lp
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def __repr__(self):
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return "{}(display_name={!r}, username={!r}, domain={!r})".format(
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self.__class__.__name__,
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self.display_name, self.username, self.domain)
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def __str__(self):
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nameset = set(self.display_name)
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if len(nameset) > len(nameset-parser.SPECIALS):
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disp = parser.quote_string(self.display_name)
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else:
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disp = self.display_name
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if disp:
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addr_spec = '' if self.addr_spec=='<>' else self.addr_spec
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return "{} <{}>".format(disp, addr_spec)
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return self.addr_spec
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def __eq__(self, other):
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if type(other) != type(self):
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return False
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return (self.display_name == other.display_name and
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self.username == other.username and
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self.domain == other.domain)
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class Group:
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def __init__(self, display_name=None, addresses=None):
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"""Create an object representing an address group.
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An address group consists of a display_name followed by colon and a
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list of addresses (see Address) terminated by a semi-colon. The Group
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is created by specifying a display_name and a possibly empty list of
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Address objects. A Group can also be used to represent a single
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address that is not in a group, which is convenient when manipulating
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lists that are a combination of Groups and individual Addresses. In
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this case the display_name should be set to None. In particular, the
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string representation of a Group whose display_name is None is the same
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as the Address object, if there is one and only one Address object in
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the addresses list.
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"""
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self._display_name = display_name
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self._addresses = tuple(addresses) if addresses else tuple()
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@property
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def display_name(self):
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return self._display_name
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@property
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def addresses(self):
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return self._addresses
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def __repr__(self):
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return "{}(display_name={!r}, addresses={!r}".format(
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self.__class__.__name__,
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self.display_name, self.addresses)
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def __str__(self):
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if self.display_name is None and len(self.addresses)==1:
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return str(self.addresses[0])
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disp = self.display_name
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if disp is not None:
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nameset = set(disp)
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if len(nameset) > len(nameset-parser.SPECIALS):
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disp = parser.quote_string(disp)
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adrstr = ", ".join(str(x) for x in self.addresses)
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adrstr = ' ' + adrstr if adrstr else adrstr
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return "{}:{};".format(disp, adrstr)
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def __eq__(self, other):
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if type(other) != type(self):
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return False
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return (self.display_name == other.display_name and
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self.addresses == other.addresses)
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# Header Classes #
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class BaseHeader(str):
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"""Base class for message headers.
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Implements generic behavior and provides tools for subclasses.
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A subclass must define a classmethod named 'parse' that takes an unfolded
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value string and a dictionary as its arguments. The dictionary will
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contain one key, 'defects', initialized to an empty list. After the call
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the dictionary must contain two additional keys: parse_tree, set to the
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parse tree obtained from parsing the header, and 'decoded', set to the
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string value of the idealized representation of the data from the value.
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(That is, encoded words are decoded, and values that have canonical
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representations are so represented.)
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The defects key is intended to collect parsing defects, which the message
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parser will subsequently dispose of as appropriate. The parser should not,
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insofar as practical, raise any errors. Defects should be added to the
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list instead. The standard header parsers register defects for RFC
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compliance issues, for obsolete RFC syntax, and for unrecoverable parsing
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errors.
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The parse method may add additional keys to the dictionary. In this case
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the subclass must define an 'init' method, which will be passed the
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dictionary as its keyword arguments. The method should use (usually by
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setting them as the value of similarly named attributes) and remove all the
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extra keys added by its parse method, and then use super to call its parent
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class with the remaining arguments and keywords.
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The subclass should also make sure that a 'max_count' attribute is defined
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that is either None or 1. XXX: need to better define this API.
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"""
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def __new__(cls, name, value):
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kwds = {'defects': []}
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cls.parse(value, kwds)
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if utils._has_surrogates(kwds['decoded']):
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kwds['decoded'] = utils._sanitize(kwds['decoded'])
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self = str.__new__(cls, kwds['decoded'])
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del kwds['decoded']
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self.init(name, **kwds)
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return self
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def init(self, name, *, parse_tree, defects):
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self._name = name
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self._parse_tree = parse_tree
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self._defects = defects
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@property
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def name(self):
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return self._name
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@property
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def defects(self):
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return tuple(self._defects)
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def __reduce__(self):
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return (
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_reconstruct_header,
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(
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self.__class__.__name__,
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self.__class__.__bases__,
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str(self),
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),
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self.__dict__)
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@classmethod
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def _reconstruct(cls, value):
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return str.__new__(cls, value)
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def fold(self, *, policy):
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"""Fold header according to policy.
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The parsed representation of the header is folded according to
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RFC5322 rules, as modified by the policy. If the parse tree
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contains surrogateescaped bytes, the bytes are CTE encoded using
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the charset 'unknown-8bit".
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Any non-ASCII characters in the parse tree are CTE encoded using
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charset utf-8. XXX: make this a policy setting.
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The returned value is an ASCII-only string possibly containing linesep
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characters, and ending with a linesep character. The string includes
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the header name and the ': ' separator.
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"""
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# At some point we need to put fws here iif it was in the source.
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header = parser.Header([
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parser.HeaderLabel([
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parser.ValueTerminal(self.name, 'header-name'),
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parser.ValueTerminal(':', 'header-sep')]),
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])
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if self._parse_tree:
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header.append(
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parser.CFWSList([parser.WhiteSpaceTerminal(' ', 'fws')]))
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header.append(self._parse_tree)
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return header.fold(policy=policy)
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def _reconstruct_header(cls_name, bases, value):
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return type(cls_name, bases, {})._reconstruct(value)
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class UnstructuredHeader:
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max_count = None
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value_parser = staticmethod(parser.get_unstructured)
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@classmethod
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def parse(cls, value, kwds):
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kwds['parse_tree'] = cls.value_parser(value)
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kwds['decoded'] = str(kwds['parse_tree'])
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class UniqueUnstructuredHeader(UnstructuredHeader):
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max_count = 1
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class DateHeader:
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"""Header whose value consists of a single timestamp.
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Provides an additional attribute, datetime, which is either an aware
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datetime using a timezone, or a naive datetime if the timezone
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in the input string is -0000. Also accepts a datetime as input.
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The 'value' attribute is the normalized form of the timestamp,
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which means it is the output of format_datetime on the datetime.
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"""
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max_count = None
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# This is used only for folding, not for creating 'decoded'.
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value_parser = staticmethod(parser.get_unstructured)
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@classmethod
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def parse(cls, value, kwds):
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if not value:
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kwds['defects'].append(errors.HeaderMissingRequiredValue())
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kwds['datetime'] = None
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kwds['decoded'] = ''
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kwds['parse_tree'] = parser.TokenList()
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return
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if isinstance(value, str):
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value = utils.parsedate_to_datetime(value)
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kwds['datetime'] = value
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kwds['decoded'] = utils.format_datetime(kwds['datetime'])
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kwds['parse_tree'] = cls.value_parser(kwds['decoded'])
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def init(self, *args, **kw):
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self._datetime = kw.pop('datetime')
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super().init(*args, **kw)
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@property
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def datetime(self):
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return self._datetime
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class UniqueDateHeader(DateHeader):
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max_count = 1
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class AddressHeader:
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max_count = None
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@staticmethod
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def value_parser(value):
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address_list, value = parser.get_address_list(value)
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assert not value, 'this should not happen'
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return address_list
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@classmethod
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def parse(cls, value, kwds):
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if isinstance(value, str):
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# We are translating here from the RFC language (address/mailbox)
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# to our API language (group/address).
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kwds['parse_tree'] = address_list = cls.value_parser(value)
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groups = []
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for addr in address_list.addresses:
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groups.append(Group(addr.display_name,
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[Address(mb.display_name or '',
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mb.local_part or '',
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mb.domain or '')
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for mb in addr.all_mailboxes]))
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defects = list(address_list.all_defects)
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else:
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# Assume it is Address/Group stuff
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if not hasattr(value, '__iter__'):
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value = [value]
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groups = [Group(None, [item]) if not hasattr(item, 'addresses')
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else item
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for item in value]
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defects = []
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kwds['groups'] = groups
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kwds['defects'] = defects
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kwds['decoded'] = ', '.join([str(item) for item in groups])
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if 'parse_tree' not in kwds:
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kwds['parse_tree'] = cls.value_parser(kwds['decoded'])
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def init(self, *args, **kw):
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self._groups = tuple(kw.pop('groups'))
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self._addresses = None
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super().init(*args, **kw)
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@property
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def groups(self):
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return self._groups
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@property
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def addresses(self):
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if self._addresses is None:
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self._addresses = tuple(address for group in self._groups
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for address in group.addresses)
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return self._addresses
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class UniqueAddressHeader(AddressHeader):
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max_count = 1
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class SingleAddressHeader(AddressHeader):
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@property
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|
def address(self):
|
||
|
|
if len(self.addresses)!=1:
|
||
|
|
raise ValueError(("value of single address header {} is not "
|
||
|
|
"a single address").format(self.name))
|
||
|
|
return self.addresses[0]
|
||
|
|
|
||
|
|
|
||
|
|
class UniqueSingleAddressHeader(SingleAddressHeader):
|
||
|
|
|
||
|
|
max_count = 1
|
||
|
|
|
||
|
|
|
||
|
|
class MIMEVersionHeader:
|
||
|
|
|
||
|
|
max_count = 1
|
||
|
|
|
||
|
|
value_parser = staticmethod(parser.parse_mime_version)
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def parse(cls, value, kwds):
|
||
|
|
kwds['parse_tree'] = parse_tree = cls.value_parser(value)
|
||
|
|
kwds['decoded'] = str(parse_tree)
|
||
|
|
kwds['defects'].extend(parse_tree.all_defects)
|
||
|
|
kwds['major'] = None if parse_tree.minor is None else parse_tree.major
|
||
|
|
kwds['minor'] = parse_tree.minor
|
||
|
|
if parse_tree.minor is not None:
|
||
|
|
kwds['version'] = '{}.{}'.format(kwds['major'], kwds['minor'])
|
||
|
|
else:
|
||
|
|
kwds['version'] = None
|
||
|
|
|
||
|
|
def init(self, *args, **kw):
|
||
|
|
self._version = kw.pop('version')
|
||
|
|
self._major = kw.pop('major')
|
||
|
|
self._minor = kw.pop('minor')
|
||
|
|
super().init(*args, **kw)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def major(self):
|
||
|
|
return self._major
|
||
|
|
|
||
|
|
@property
|
||
|
|
def minor(self):
|
||
|
|
return self._minor
|
||
|
|
|
||
|
|
@property
|
||
|
|
def version(self):
|
||
|
|
return self._version
|
||
|
|
|
||
|
|
|
||
|
|
class ParameterizedMIMEHeader:
|
||
|
|
|
||
|
|
# Mixin that handles the params dict. Must be subclassed and
|
||
|
|
# a property value_parser for the specific header provided.
|
||
|
|
|
||
|
|
max_count = 1
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def parse(cls, value, kwds):
|
||
|
|
kwds['parse_tree'] = parse_tree = cls.value_parser(value)
|
||
|
|
kwds['decoded'] = str(parse_tree)
|
||
|
|
kwds['defects'].extend(parse_tree.all_defects)
|
||
|
|
if parse_tree.params is None:
|
||
|
|
kwds['params'] = {}
|
||
|
|
else:
|
||
|
|
# The MIME RFCs specify that parameter ordering is arbitrary.
|
||
|
|
kwds['params'] = {utils._sanitize(name).lower():
|
||
|
|
utils._sanitize(value)
|
||
|
|
for name, value in parse_tree.params}
|
||
|
|
|
||
|
|
def init(self, *args, **kw):
|
||
|
|
self._params = kw.pop('params')
|
||
|
|
super().init(*args, **kw)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def params(self):
|
||
|
|
return MappingProxyType(self._params)
|
||
|
|
|
||
|
|
|
||
|
|
class ContentTypeHeader(ParameterizedMIMEHeader):
|
||
|
|
|
||
|
|
value_parser = staticmethod(parser.parse_content_type_header)
|
||
|
|
|
||
|
|
def init(self, *args, **kw):
|
||
|
|
super().init(*args, **kw)
|
||
|
|
self._maintype = utils._sanitize(self._parse_tree.maintype)
|
||
|
|
self._subtype = utils._sanitize(self._parse_tree.subtype)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def maintype(self):
|
||
|
|
return self._maintype
|
||
|
|
|
||
|
|
@property
|
||
|
|
def subtype(self):
|
||
|
|
return self._subtype
|
||
|
|
|
||
|
|
@property
|
||
|
|
def content_type(self):
|
||
|
|
return self.maintype + '/' + self.subtype
|
||
|
|
|
||
|
|
|
||
|
|
class ContentDispositionHeader(ParameterizedMIMEHeader):
|
||
|
|
|
||
|
|
value_parser = staticmethod(parser.parse_content_disposition_header)
|
||
|
|
|
||
|
|
def init(self, *args, **kw):
|
||
|
|
super().init(*args, **kw)
|
||
|
|
cd = self._parse_tree.content_disposition
|
||
|
|
self._content_disposition = cd if cd is None else utils._sanitize(cd)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def content_disposition(self):
|
||
|
|
return self._content_disposition
|
||
|
|
|
||
|
|
|
||
|
|
class ContentTransferEncodingHeader:
|
||
|
|
|
||
|
|
max_count = 1
|
||
|
|
|
||
|
|
value_parser = staticmethod(parser.parse_content_transfer_encoding_header)
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def parse(cls, value, kwds):
|
||
|
|
kwds['parse_tree'] = parse_tree = cls.value_parser(value)
|
||
|
|
kwds['decoded'] = str(parse_tree)
|
||
|
|
kwds['defects'].extend(parse_tree.all_defects)
|
||
|
|
|
||
|
|
def init(self, *args, **kw):
|
||
|
|
super().init(*args, **kw)
|
||
|
|
self._cte = utils._sanitize(self._parse_tree.cte)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def cte(self):
|
||
|
|
return self._cte
|
||
|
|
|
||
|
|
|
||
|
|
# The header factory #
|
||
|
|
|
||
|
|
_default_header_map = {
|
||
|
|
'subject': UniqueUnstructuredHeader,
|
||
|
|
'date': UniqueDateHeader,
|
||
|
|
'resent-date': DateHeader,
|
||
|
|
'orig-date': UniqueDateHeader,
|
||
|
|
'sender': UniqueSingleAddressHeader,
|
||
|
|
'resent-sender': SingleAddressHeader,
|
||
|
|
'to': UniqueAddressHeader,
|
||
|
|
'resent-to': AddressHeader,
|
||
|
|
'cc': UniqueAddressHeader,
|
||
|
|
'resent-cc': AddressHeader,
|
||
|
|
'bcc': UniqueAddressHeader,
|
||
|
|
'resent-bcc': AddressHeader,
|
||
|
|
'from': UniqueAddressHeader,
|
||
|
|
'resent-from': AddressHeader,
|
||
|
|
'reply-to': UniqueAddressHeader,
|
||
|
|
'mime-version': MIMEVersionHeader,
|
||
|
|
'content-type': ContentTypeHeader,
|
||
|
|
'content-disposition': ContentDispositionHeader,
|
||
|
|
'content-transfer-encoding': ContentTransferEncodingHeader,
|
||
|
|
}
|
||
|
|
|
||
|
|
class HeaderRegistry:
|
||
|
|
|
||
|
|
"""A header_factory and header registry."""
|
||
|
|
|
||
|
|
def __init__(self, base_class=BaseHeader, default_class=UnstructuredHeader,
|
||
|
|
use_default_map=True):
|
||
|
|
"""Create a header_factory that works with the Policy API.
|
||
|
|
|
||
|
|
base_class is the class that will be the last class in the created
|
||
|
|
header class's __bases__ list. default_class is the class that will be
|
||
|
|
used if "name" (see __call__) does not appear in the registry.
|
||
|
|
use_default_map controls whether or not the default mapping of names to
|
||
|
|
specialized classes is copied in to the registry when the factory is
|
||
|
|
created. The default is True.
|
||
|
|
|
||
|
|
"""
|
||
|
|
self.registry = {}
|
||
|
|
self.base_class = base_class
|
||
|
|
self.default_class = default_class
|
||
|
|
if use_default_map:
|
||
|
|
self.registry.update(_default_header_map)
|
||
|
|
|
||
|
|
def map_to_type(self, name, cls):
|
||
|
|
"""Register cls as the specialized class for handling "name" headers.
|
||
|
|
|
||
|
|
"""
|
||
|
|
self.registry[name.lower()] = cls
|
||
|
|
|
||
|
|
def __getitem__(self, name):
|
||
|
|
cls = self.registry.get(name.lower(), self.default_class)
|
||
|
|
return type('_'+cls.__name__, (cls, self.base_class), {})
|
||
|
|
|
||
|
|
def __call__(self, name, value):
|
||
|
|
"""Create a header instance for header 'name' from 'value'.
|
||
|
|
|
||
|
|
Creates a header instance by creating a specialized class for parsing
|
||
|
|
and representing the specified header by combining the factory
|
||
|
|
base_class with a specialized class from the registry or the
|
||
|
|
default_class, and passing the name and value to the constructed
|
||
|
|
class's constructor.
|
||
|
|
|
||
|
|
"""
|
||
|
|
return self[name](name, value)
|