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			586 lines
		
	
	
	
		
			20 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			586 lines
		
	
	
	
		
			20 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""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 represeting 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 an
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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 only put fws here if 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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            parser.CFWSList([parser.WhiteSpaceTerminal(' ', 'fws')]),
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                             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):
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        if len(self.addresses)!=1:
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            raise ValueError(("value of single address header {} is not "
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                "a single address").format(self.name))
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        return self.addresses[0]
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class UniqueSingleAddressHeader(SingleAddressHeader):
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    max_count = 1
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class MIMEVersionHeader:
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    max_count = 1
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    value_parser = staticmethod(parser.parse_mime_version)
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    @classmethod
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    def parse(cls, value, kwds):
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        kwds['parse_tree'] = parse_tree = cls.value_parser(value)
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        kwds['decoded'] = str(parse_tree)
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        kwds['defects'].extend(parse_tree.all_defects)
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        kwds['major'] = None if parse_tree.minor is None else parse_tree.major
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        kwds['minor'] = parse_tree.minor
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        if parse_tree.minor is not None:
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            kwds['version'] = '{}.{}'.format(kwds['major'], kwds['minor'])
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        else:
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            kwds['version'] = None
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    def init(self, *args, **kw):
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        self._version = kw.pop('version')
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        self._major = kw.pop('major')
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        self._minor = kw.pop('minor')
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        super().init(*args, **kw)
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    @property
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    def major(self):
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        return self._major
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    @property
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    def minor(self):
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        return self._minor
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    @property
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    def version(self):
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        return self._version
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class ParameterizedMIMEHeader:
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    # Mixin that handles the params dict.  Must be subclassed and
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    # a property value_parser for the specific header provided.
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    max_count = 1
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    @classmethod
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    def parse(cls, value, kwds):
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        kwds['parse_tree'] = parse_tree = cls.value_parser(value)
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        kwds['decoded'] = str(parse_tree)
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        kwds['defects'].extend(parse_tree.all_defects)
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        if parse_tree.params is None:
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            kwds['params'] = {}
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        else:
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            # The MIME RFCs specify that parameter ordering is arbitrary.
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            kwds['params'] = {utils._sanitize(name).lower():
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                                    utils._sanitize(value)
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                               for name, value in parse_tree.params}
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    def init(self, *args, **kw):
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        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)
 |