# Copyright (C) 2001-2007 Python Software Foundation

# Author: Barry Warsaw

# Contact: email-sig@python.org

"""Basic message object for the email package object model."""

__all__ = ['Message', 'EmailMessage']

import binascii

import re

import quopri

from io import BytesIO, StringIO

# Intrapackage imports

from email import utils

from email import errors

from email._policybase import compat32

from email import charset as _charset

from email._encoded_words import decode_b

Charset = _charset.Charset

SEMISPACE = '; '

# Regular expression that matches `special' characters in parameters, the

# existence of which force quoting of the parameter value.

tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]')

def _splitparam(param):

# Split header parameters. BAW: this may be too simple. It isn't

# strictly RFC 2045 (section 5.1) compliant, but it catches most headers

# found in the wild. We may eventually need a full fledged parser.

# RDM: we might have a Header here; for now just stringify it.

a, sep, b = str(param).partition(';')

if not sep:

return a.strip(), None

return a.strip(), b.strip()

def _formatparam(param, value=None, quote=True):

"""Convenience function to format and return a key=value pair.

This will quote the value if needed or if quote is true. If value is a

three tuple (charset, language, value), it will be encoded according

to RFC2231 rules. If it contains non-ascii characters it will likewise

be encoded according to RFC2231 rules, using the utf-8 charset and

a null language.

"""

if value is not None and len(value) > 0:

# A tuple is used for RFC 2231 encoded parameter values where items

# are (charset, language, value). charset is a string, not a Charset

# instance. RFC 2231 encoded values are never quoted, per RFC.

if isinstance(value, tuple):

# Encode as per RFC 2231

param += '*'

value = utils.encode_rfc2231(value[2], value[0], value[1])

return '%s=%s' % (param, value)

else:

try:

value.encode('ascii')

except UnicodeEncodeError:

param += '*'

value = utils.encode_rfc2231(value, 'utf-8', '')

return '%s=%s' % (param, value)

# BAW: Please check this. I think that if quote is set it should

# force quoting even if not necessary.

if quote or tspecials.search(value):

return '%s="%s"' % (param, utils.quote(value))

else:

return '%s=%s' % (param, value)

else:

return param

def _parseparam(s):

# RDM This might be a Header, so for now stringify it.

s = ';' + str(s)

plist = []

start = 0

while s.find(';', start) == start:

start += 1

end = s.find(';', start)

ind, diff = start, 0

while end > 0:

diff += s.count('"', ind, end) - s.count('\\"', ind, end)

if diff % 2 == 0:

break

end, ind = ind, s.find(';', end + 1)

if end < 0:

end = len(s)

i = s.find('=', start, end)

if i == -1:

f = s[start:end]

else:

f = s[start:i].rstrip().lower() + '=' + s[i+1:end].lstrip()

plist.append(f.strip())

start = end

return plist

def _unquotevalue(value):

# This is different than utils.collapse_rfc2231_value() because it doesn't

# try to convert the value to a str. Message.get_param() and

# Message.get_params() are both currently defined to return the tuple in

# the face of RFC 2231 parameters.

if isinstance(value, tuple):

return value[0], value[1], utils.unquote(value[2])

else:

return utils.unquote(value)

def _decode_uu(encoded):

"""Decode uuencoded data."""

decoded_lines = []

encoded_lines_iter = iter(encoded.splitlines())

for line in encoded_lines_iter:

if line.startswith(b"begin "):

mode, _, path = line.removeprefix(b"begin ").partition(b" ")

try:

int(mode, base=8)

except ValueError:

continue

else:

break

else:

raise ValueError("`begin` line not found")

for line in encoded_lines_iter:

if not line:

raise ValueError("Truncated input")

elif line.strip(b' \t\r\n\f') == b'end':

break

try:

decoded_line = binascii.a2b_uu(line)

except binascii.Error:

# Workaround for broken uuencoders by /Fredrik Lundh

nbytes = (((line[0]-32) & 63) * 4 + 5) // 3

decoded_line = binascii.a2b_uu(line[:nbytes])

decoded_lines.append(decoded_line)

return b''.join(decoded_lines)

class Message:

"""Basic message object.

A message object is defined as something that has a bunch of RFC 5322

headers and a payload. It may optionally have an envelope header

(a.k.a. Unix-From or From_ header). If the message is a container (i.e. a

multipart or a message/rfc822), then the payload is a list of Message

objects, otherwise it is a string.

Message objects implement part of the `mapping' interface, which assumes

there is exactly one occurrence of the header per message. Some headers

do in fact appear multiple times (e.g. Received) and for those headers,

you must use the explicit API to set or get all the headers. Not all of

the mapping methods are implemented.

"""

def __init__(self, policy=compat32):

self.policy = policy

self._headers = []

self._unixfrom = None

self._payload = None

self._charset = None

# Defaults for multipart messages

self.preamble = self.epilogue = None

self.defects = []

# Default content type

self._default_type = 'text/plain'

def __str__(self):

"""Return the entire formatted message as a string.

"""

return self.as_string()

def as_string(self, unixfrom=False, maxheaderlen=0, policy=None):

"""Return the entire formatted message as a string.

Optional 'unixfrom', when true, means include the Unix From_ envelope

header. For backward compatibility reasons, if maxheaderlen is

not specified it defaults to 0, so you must override it explicitly

if you want a different maxheaderlen. 'policy' is passed to the

Generator instance used to serialize the message; if it is not

specified the policy associated with the message instance is used.

If the message object contains binary data that is not encoded

according to RFC standards, the non-compliant data will be replaced by

Unicode "unknown character" code points.

"""

from email.generator import Generator

policy = self.policy if policy is None else policy

fp = StringIO()

g = Generator(fp,

mangle_from_=False,

maxheaderlen=maxheaderlen,

policy=policy)

g.flatten(self, unixfrom=unixfrom)

return fp.getvalue()

def __bytes__(self):

"""Return the entire formatted message as a bytes object.

"""

return self.as_bytes()

def as_bytes(self, unixfrom=False, policy=None):

"""Return the entire formatted message as a bytes object.

Optional 'unixfrom', when true, means include the Unix From_ envelope

header. 'policy' is passed to the BytesGenerator instance used to

serialize the message; if not specified the policy associated with

the message instance is used.

"""

from email.generator import BytesGenerator

policy = self.policy if policy is None else policy

fp = BytesIO()

g = BytesGenerator(fp, mangle_from_=False, policy=policy)

g.flatten(self, unixfrom=unixfrom)

return fp.getvalue()

def is_multipart(self):

"""Return True if the message consists of multiple parts."""

return isinstance(self._payload, list)

#

# Unix From_ line

#

def set_unixfrom(self, unixfrom):

self._unixfrom = unixfrom

def get_unixfrom(self):

return self._unixfrom

#

# Payload manipulation.

#

def attach(self, payload):

"""Add the given payload to the current payload.

The current payload will always be a list of objects after this method

is called. If you want to set the payload to a scalar object, use

set_payload() instead.

"""

if self._payload is None:

self._payload = [payload]

else:

try:

self._payload.append(payload)

except AttributeError:

raise TypeError("Attach is not valid on a message with a"

" non-multipart payload")

def get_payload(self, i=None, decode=False):

"""Return a reference to the payload.

The payload will either be a list object or a string. If you mutate

the list object, you modify the message's payload in place. Optional

i returns that index into the payload.

Optional decode is a flag indicating whether the payload should be

decoded or not, according to the Content-Transfer-Encoding header

(default is False).

When True and the message is not a multipart, the payload will be

decoded if this header's value is `quoted-printable' or `base64'. If

some other encoding is used, or the header is missing, or if the

payload has bogus data (i.e. bogus base64 or uuencoded data), the

payload is returned as-is.

If the message is a multipart and the decode flag is True, then None

is returned.

"""

# Here is the logic table for this code, based on the email5.0.0 code:

# i decode is_multipart result

# ------ ------ ------------ ------------------------------

# None True True None

# i True True None

# None False True _payload (a list)

# i False True _payload element i (a Message)

# i False False error (not a list)

# i True False error (not a list)

# None False False _payload

# None True False _payload decoded (bytes)

# Note that Barry planned to factor out the 'decode' case, but that

# isn't so easy now that we handle the 8 bit data, which needs to be

# converted in both the decode and non-decode path.

if self.is_multipart():

if decode:

return None

if i is None:

return self._payload

else:

return self._payload[i]

# For backward compatibility, Use isinstance and this error message

# instead of the more logical is_multipart test.

if i is not None and not isinstance(self._payload, list):

raise TypeError('Expected list, got %s' % type(self._payload))

payload = self._payload

cte = self.get('content-transfer-encoding', '')

if hasattr(cte, 'cte'):

cte = cte.cte

else:

# cte might be a Header, so for now stringify it.

cte = str(cte).strip().lower()

# payload may be bytes here.

if not decode:

if isinstance(payload, str) and utils._has_surrogates(payload):

try:

bpayload = payload.encode('ascii', 'surrogateescape')

try:

payload = bpayload.decode(self.get_content_charset('ascii'), 'replace')

except LookupError:

payload = bpayload.decode('ascii', 'replace')

except UnicodeEncodeError:

pass

return payload

if isinstance(payload, str):

try:

bpayload = payload.encode('ascii', 'surrogateescape')

except UnicodeEncodeError:

# This won't happen for RFC compliant messages (messages

# containing only ASCII code points in the string input).

# If it does happen, turn the string into bytes in a way

# guaranteed not to fail.

bpayload = payload.encode('raw-unicode-escape')

else:

bpayload = payload

if cte == 'quoted-printable':

return quopri.decodestring(bpayload)

elif cte == 'base64':

# XXX: this is a bit of a hack; decode_b should probably be factored

# out somewhere, but I haven't figured out where yet.

value, defects = decode_b(b''.join(bpayload.splitlines()))

for defect in defects:

self.policy.handle_defect(self, defect)

return value

elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'):

try:

return _decode_uu(bpayload)

except ValueError:

# Some decoding problem.

return bpayload

if isinstance(payload, str):

return bpayload

return payload

def set_payload(self, payload, charset=None):

"""Set the payload to the given value.

Optional charset sets the message's default character set. See

set_charset() for details.

"""

if hasattr(payload, 'encode'):

if charset is None:

self._payload = payload

return

if not isinstance(charset, Charset):

charset = Charset(charset)

payload = payload.encode(charset.output_charset, 'surrogateescape')

if hasattr(payload, 'decode'):

self._payload = payload.decode('ascii', 'surrogateescape')

else:

self._payload = payload

if charset is not None:

self.set_charset(charset)

def set_charset(self, charset):

"""Set the charset of the payload to a given character set.

charset can be a Charset instance, a string naming a character set, or

None. If it is a string it will be converted to a Charset instance.

If charset is None, the charset parameter will be removed from the

Content-Type field. Anything else will generate a TypeError.

The message will be assumed to be of type text/* encoded with

charset.input_charset. It will be converted to charset.output_charset

and encoded properly, if needed, when generating the plain text

representation of the message. MIME headers (MIME-Version,

Content-Type, Content-Transfer-Encoding) will be added as needed.

"""

if charset is None:

self.del_param('charset')

self._charset = None

return

if not isinstance(charset, Charset):

charset = Charset(charset)

self._charset = charset

if 'MIME-Version' not in self:

self.add_header('MIME-Version', '1.0')

if 'Content-Type' not in self:

self.add_header('Content-Type', 'text/plain',

charset=charset.get_output_charset())

else:

self.set_param('charset', charset.get_output_charset())

if charset != charset.get_output_charset():

self._payload = charset.body_encode(self._payload)

if 'Content-Transfer-Encoding' not in self:

cte = charset.get_body_encoding()

try:

cte(self)

except TypeError:

# This 'if' is for backward compatibility, it allows str

# through even though that won't work correctly if the

# message is serialized.

payload = self._payload

if payload:

try:

payload = payload.encode('ascii', 'surrogateescape')

except UnicodeError:

payload = payload.encode(charset.output_charset)

self._payload = charset.body_encode(payload)

self.add_header('Content-Transfer-Encoding', cte)

def get_charset(self):

"""Return the Charset instance associated with the message's payload.

"""

return self._charset

#

# MAPPING INTERFACE (partial)

#

def __len__(self):

"""Return the total number of headers, including duplicates."""

return len(self._headers)

def __getitem__(self, name):

"""Get a header value.

Return None if the header is missing instead of raising an exception.

Note that if the header appeared multiple times, exactly which

occurrence gets returned is undefined. Use get_all() to get all

the values matching a header field name.

"""

return self.get(name)

def __setitem__(self, name, val):

"""Set the value of a header.

Note: this does not overwrite an existing header with the same field

name. Use __delitem__() first to delete any existing headers.

"""

max_count = self.policy.header_max_count(name)

if max_count:

lname = name.lower()

found = 0

for k, v in self._headers:

if k.lower() == lname:

found += 1

if found >= max_count:

raise ValueError("There may be at most {} {} headers "

"in a message".format(max_count, name))

self._headers.append(self.policy.header_store_parse(name, val))

def __delitem__(self, name):

"""Delete all occurrences of a header, if present.

Does not raise an exception if the header is missing.

"""

name = name.lower()

newheaders = []

for k, v in self._headers:

if k.lower() != name:

newheaders.append((k, v))

self._headers = newheaders

def __contains__(self, name):

name_lower = name.lower()

for k, v in self._headers:

if name_lower == k.lower():

return True

return False

def __iter__(self):

for field, value in self._headers:

yield field

def keys(self):

"""Return a list of all the message's header field names.

These will be sorted in the order they appeared in the original

message, or were added to the message, and may contain duplicates.

Any fields deleted and re-inserted are always appended to the header

list.

"""

return [k for k, v in self._headers]

def values(self):

"""Return a list of all the message's header values.

These will be sorted in the order they appeared in the original

message, or were added to the message, and may contain duplicates.

Any fields deleted and re-inserted are always appended to the header

list.

"""

return [self.policy.header_fetch_parse(k, v)

for k, v in self._headers]

def items(self):

"""Get all the message's header fields and values.

These will be sorted in the order they appeared in the original

message, or were added to the message, and may contain duplicates.

Any fields deleted and re-inserted are always appended to the header

list.

"""

return [(k, self.policy.header_fetch_parse(k, v))

for k, v in self._headers]

def get(self, name, failobj=None):

"""Get a header value.

Like __getitem__() but return failobj instead of None when the field

is missing.

"""

name = name.lower()

for k, v in self._headers:

if k.lower() == name:

return self.policy.header_fetch_parse(k, v)

return failobj

#

# "Internal" methods (public API, but only intended for use by a parser

# or generator, not normal application code.

#

def set_raw(self, name, value):

"""Store name and value in the model without modification.

This is an "internal" API, intended only for use by a parser.

"""

self._headers.append((name, value))

def raw_items(self):

"""Return the (name, value) header pairs without modification.

This is an "internal" API, intended only for use by a generator.

"""

return iter(self._headers.copy())

#

# Additional useful stuff

#

def get_all(self, name, failobj=None):

"""Return a list of all the values for the named field.

These will be sorted in the order they appeared in the original

message, and may contain duplicates. Any fields deleted and

re-inserted are always appended to the header list.

If no such fields exist, failobj is returned (defaults to None).

"""

values = []

name = name.lower()

for k, v in self._headers:

if k.lower() == name:

values.append(self.policy.header_fetch_parse(k, v))

if not values:

return failobj

return values

def add_header(self, _name, _value, **_params):

"""Extended header setting.

name is the header field to add. keyword arguments can be used to set

additional parameters for the header field, with underscores converted

to dashes. Normally the parameter will be added as key="value" unless

value is None, in which case only the key will be added. If a

parameter value contains non-ASCII characters it can be specified as a

three-tuple of (charset, language, value), in which case it will be

encoded according to RFC2231 rules. Otherwise it will be encoded using

the utf-8 charset and a language of ''.

Examples:

msg.add_header('content-disposition', 'attachment', filename='bud.gif')

msg.add_header('content-disposition', 'attachment',

filename=('utf-8', '', 'Fußballer.ppt'))

msg.add_header('content-disposition', 'attachment',

filename='Fußballer.ppt'))

"""

parts = []

for k, v in _params.items():

if v is None:

parts.append(k.replace('_', '-'))

else:

parts.append(_formatparam(k.replace('_', '-'), v))

if _value is not None:

parts.insert(0, _value)

self[_name] = SEMISPACE.join(parts)

def replace_header(self, _name, _value):

"""Replace a header.

Replace the first matching header found in the message, retaining

header order and case. If no matching header was found, a KeyError is

raised.

"""

_name = _name.lower()

for i, (k, v) in zip(range(len(self._headers)), self._headers):

if k.lower() == _name:

self._headers[i] = self.policy.header_store_parse(k, _value)

break

else:

raise KeyError(_name)

#

# Use these three methods instead of the three above.

#

def get_content_type(self):

"""Return the message's content type.

The returned string is coerced to lower case of the form

`maintype/subtype'. If there was no Content-Type header in the

message, the default type as given by get_default_type() will be

returned. Since according to RFC 2045, messages always have a default

type this will always return a value.

RFC 2045 defines a message's default type to be text/plain unless it

appears inside a multipart/digest container, in which case it would be

message/rfc822.

"""

missing = object()

value = self.get('content-type', missing)

if value is missing:

# This should have no parameters

return self.get_default_type()

ctype = _splitparam(value)[0].lower()

# RFC 2045, section 5.2 says if its invalid, use text/plain

if ctype.count('/') != 1:

return 'text/plain'

return ctype

def get_content_maintype(self):

"""Return the message's main content type.

This is the `maintype' part of the string returned by

get_content_type().

"""

ctype = self.get_content_type()

return ctype.split('/')[0]

def get_content_subtype(self):

"""Returns the message's sub-content type.

This is the `subtype' part of the string returned by

get_content_type().

"""

ctype = self.get_content_type()

return ctype.split('/')[1]

def get_default_type(self):

"""Return the `default' content type.

Most messages have a default content type of text/plain, except for

messages that are subparts of multipart/digest containers. Such

subparts have a default content type of message/rfc822.

"""

return self._default_type

def set_default_type(self, ctype):

"""Set the `default' content type.

ctype should be either "text/plain" or "message/rfc822", although this

is not enforced. The default content type is not stored in the

Content-Type header.

"""

self._default_type = ctype

def _get_params_preserve(self, failobj, header):

# Like get_params() but preserves the quoting of values. BAW:

# should this be part of the public interface?

missing = object()

value = self.get(header, missing)

if value is missing:

return failobj

params = []

for p in _parseparam(value):

try:

name, val = p.split('=', 1)

name = name.strip()

val = val.strip()

except ValueError:

# Must have been a bare attribute

name = p.strip()

val = ''

params.append((name, val))

params = utils.decode_params(params)

return params

def get_params(self, failobj=None, header='content-type', unquote=True):

"""Return the message's Content-Type parameters, as a list.

The elements of the returned list are 2-tuples of key/value pairs, as

split on the `=' sign. The left hand side of the `=' is the key,

while the right hand side is the value. If there is no `=' sign in

the parameter the value is the empty string. The value is as

described in the get_param() method.

Optional failobj is the object to return if there is no Content-Type

header. Optional header is the header to search instead of

Content-Type. If unquote is True, the value is unquoted.

"""

missing = object()

params = self._get_params_preserve(missing, header)

if params is missing:

return failobj

if unquote:

return [(k, _unquotevalue(v)) for k, v in params]

else:

return params

def get_param(self, param, failobj=None, header='content-type',

unquote=True):

"""Return the parameter value if found in the Content-Type header.

Optional failobj is the object to return if there is no Content-Type

header, or the Content-Type header has no such parameter. Optional

header is the header to search instead of Content-Type.

Parameter keys are always compared case insensitively. The return

value can either be a string, or a 3-tuple if the parameter was RFC

2231 encoded. When it's a 3-tuple, the elements of the value are of

the form (CHARSET, LANGUAGE, VALUE). Note that both CHARSET and

LANGUAGE can be None, in which case you should consider VALUE to be

encoded in the us-ascii charset. You can usually ignore LANGUAGE.

The parameter value (either the returned string, or the VALUE item in

the 3-tuple) is always unquoted, unless unquote is set to False.

If your application doesn't care whether the parameter was RFC 2231

encoded, it can turn the return value into a string as follows:

rawparam = msg.get_param('foo')

param = email.utils.collapse_rfc2231_value(rawparam)

"""

if header not in self:

return failobj

for k, v in self._get_params_preserve(failobj, header):

if k.lower() == param.lower():

if unquote:

return _unquotevalue(v)

else:

return v

return failobj

def set_param(self, param, value, header='Content-Type', requote=True,

charset=None, language='', replace=False):

"""Set a parameter in the Content-Type header.

If the parameter already exists in the header, its value will be

replaced with the new value.

If header is Content-Type and has not yet been defined for this

message, it will be set to "text/plain" and the new parameter and

value will be appended as per RFC 2045.

An alternate header can be specified in the header argument, and all

parameters will be quoted as necessary unless requote is False.

If charset is specified, the parameter will be encoded according to RFC

2231. Optional language specifies the RFC 2231 language, defaulting

to the empty string. Both charset and language should be strings.

"""

if not isinstance(value, tuple) and charset:

value = (charset, language, value)

if header not in self and header.lower() == 'content-type':

ctype = 'text/plain'

else:

ctype = self.get(header)

if not self.get_param(param, header=header):

if not ctype:

ctype = _formatparam(param, value, requote)

else:

ctype = SEMISPACE.join(

[ctype, _formatparam(param, value, requote)])

else:

ctype = ''

for old_param, old_value in self.get_params(header=header,

unquote=requote):

append_param = ''

if old_param.lower() == param.lower():

append_param = _formatparam(param, value, requote)

else:

append_param = _formatparam(old_param, old_value, requote)

if not ctype:

ctype = append_param

else:

ctype = SEMISPACE.join([ctype, append_param])

if ctype != self.get(header):

if replace:

self.replace_header(header, ctype)

else:

del self[header]

self[header] = ctype

def del_param(self, param, header='content-type', requote=True):

"""Remove the given parameter completely from the Content-Type header.

The header will be re-written in place without the parameter or its

value. All values will be quoted as necessary unless requote is

False. Optional header specifies an alternative to the Content-Type

header.

"""

if header not in self:

return

new_ctype = ''

for p, v in self.get_params(header=header, unquote=requote):

if p.lower() != param.lower():

if not new_ctype:

new_ctype = _formatparam(p, v, requote)

else:

new_ctype = SEMISPACE.join([new_ctype,

_formatparam(p, v, requote)])

if new_ctype != self.get(header):

del self[header]

self[header] = new_ctype

def set_type(self, type, header='Content-Type', requote=True):

"""Set the main type and subtype for the Content-Type header.

type must be a string in the form "maintype/subtype", otherwise a

ValueError is raised.

This method replaces the Content-Type header, keeping all the

parameters in place. If requote is False, this leaves the existing

header's quoting as is. Otherwise, the parameters will be quoted (the

default).

An alternative header can be specified in the header argument. When

the Content-Type header is set, we'll always also add a MIME-Version

header.

"""

# BAW: should we be strict?

if not type.count('/') == 1:

raise ValueError

# Set the Content-Type, you get a MIME-Version

if header.lower() == 'content-type':

del self['mime-version']

self['MIME-Version'] = '1.0'

if header not in self:

self[header] = type

return

params = self.get_params(header=header, unquote=requote)

del self[header]

self[header] = type

# Skip the first param; it's the old type.

for p, v in params[1:]:

self.set_param(p, v, header, requote)

def get_filename(self, failobj=None):

"""Return the filename associated with the payload if present.

The filename is extracted from the Content-Disposition header's

`filename' parameter, and it is unquoted. If that header is missing

the `filename' parameter, this method falls back to looking for the

`name' parameter.

"""

missing = object()

filename = self.get_param('filename', missing, 'content-disposition')

if filename is missing:

filename = self.get_param('name', missing, 'content-type')

if filename is missing:

return failobj

return utils.collapse_rfc2231_value(filename).strip()

def get_boundary(self, failobj=None):

"""Return the boundary associated with the payload if present.

The boundary is extracted from the Content-Type header's `boundary'

parameter, and it is unquoted.

"""

missing = object()

boundary = self.get_param('boundary', missing)

if boundary is missing:

return failobj

# RFC 2046 says that boundaries may begin but not end in w/s

return utils.collapse_rfc2231_value(boundary).rstrip()

def set_boundary(self, boundary):

"""Set the boundary parameter in Content-Type to 'boundary'.

This is subtly different than deleting the Content-Type header and

adding a new one with a new boundary parameter via add_header(). The

main difference is that using the set_boundary() method preserves the

order of the Content-Type header in the original message.

HeaderParseError is raised if the message has no Content-Type header.

"""

missing = object()

params = self._get_params_preserve(missing, 'content-type')

if params is missing:

# There was no Content-Type header, and we don't know what type

# to set it to, so raise an exception.

raise errors.HeaderParseError('No Content-Type header found')

newparams = []

foundp = False

for pk, pv in params:

if pk.lower() == 'boundary':

newparams.append(('boundary', '"%s"' % boundary))

foundp = True

else:

newparams.append((pk, pv))

if not foundp:

# The original Content-Type header had no boundary attribute.

# Tack one on the end. BAW: should we raise an exception

# instead???

newparams.append(('boundary', '"%s"' % boundary))

# Replace the existing Content-Type header with the new value

newheaders = []

for h, v in self._headers:

if h.lower() == 'content-type':

parts = []

for k, v in newparams:

if v == '':

parts.append(k)

else:

parts.append('%s=%s' % (k, v))

val = SEMISPACE.join(parts)

newheaders.append(self.policy.header_store_parse(h, val))

else:

newheaders.append((h, v))

self._headers = newheaders

def get_content_charset(self, failobj=None):

"""Return the charset parameter of the Content-Type header.

The returned string is always coerced to lower case. If there is no

Content-Type header, or if that header has no charset parameter,

failobj is returned.

"""

missing = object()

charset = self.get_param('charset', missing)

if charset is missing:

return failobj

if isinstance(charset, tuple):

# RFC 2231 encoded, so decode it, and it better end up as ascii.

pcharset = charset[0] or 'us-ascii'

try:

# LookupError will be raised if the charset isn't known to

# Python. UnicodeError will be raised if the encoded text

# contains a character not in the charset.

as_bytes = charset[2].encode('raw-unicode-escape')

charset = str(as_bytes, pcharset)

except (LookupError, UnicodeError):

charset = charset[2]

# charset characters must be in us-ascii range

try:

charset.encode('us-ascii')

except UnicodeError:

return failobj

# RFC 2046, $4.1.2 says charsets are not case sensitive

return charset.lower()

def get_charsets(self, failobj=None):

"""Return a list containing the charset(s) used in this message.

The returned list of items describes the Content-Type headers'

charset parameter for this message and all the subparts in its

payload.

Each item will either be a string (the value of the charset parameter

in the Content-Type header of that part) or the value of the

'failobj' parameter (defaults to None), if the part does not have a

main MIME type of "text", or the charset is not defined.

The list will contain one string for each part of the message, plus

one for the container message (i.e. self), so that a non-multipart

message will still return a list of length 1.

"""

return [part.get_content_charset(failobj) for part in self.walk()]

def get_content_disposition(self):

"""Return the message's content-disposition if it exists, or None.

The return values can be either 'inline', 'attachment' or None

according to the rfc2183.

"""

value = self.get('content-disposition')

if value is None:

return None

c_d = _splitparam(value)[0].lower()

return c_d

# I.e. def walk(self): ...

from email.iterators import walk

class MIMEPart(Message):

def __init__(self, policy=None):

if policy is None:

from email.policy import default

policy = default

super().__init__(policy)

def as_string(self, unixfrom=False, maxheaderlen=None, policy=None):

"""Return the entire formatted message as a string.