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import binascii
import email.charset
import email.message
import email.errors
from email import quoprimime
class ContentManager:
def __init__(self):
self.get_handlers = {}
self.set_handlers = {}
def add_get_handler(self, key, handler):
self.get_handlers[key] = handler
def get_content(self, msg, *args, **kw):
content_type = msg.get_content_type()
if content_type in self.get_handlers:
return self.get_handlers[content_type](msg, *args, **kw)
maintype = msg.get_content_maintype()
if maintype in self.get_handlers:
return self.get_handlers[maintype](msg, *args, **kw)
if '' in self.get_handlers:
return self.get_handlers[''](msg, *args, **kw)
raise KeyError(content_type)
def add_set_handler(self, typekey, handler):
self.set_handlers[typekey] = handler
def set_content(self, msg, obj, *args, **kw):
if msg.get_content_maintype() == 'multipart':
# XXX: is this error a good idea or not? We can remove it later,
# but we can't add it later, so do it for now.
raise TypeError("set_content not valid on multipart")
handler = self._find_set_handler(msg, obj)
msg.clear_content()
handler(msg, obj, *args, **kw)
def _find_set_handler(self, msg, obj):
full_path_for_error = None
for typ in type(obj).__mro__:
if typ in self.set_handlers:
return self.set_handlers[typ]
qname = typ.__qualname__
modname = getattr(typ, '__module__', '')
full_path = '.'.join((modname, qname)) if modname else qname
if full_path_for_error is None:
full_path_for_error = full_path
if full_path in self.set_handlers:
return self.set_handlers[full_path]
if qname in self.set_handlers:
return self.set_handlers[qname]
name = typ.__name__
if name in self.set_handlers:
return self.set_handlers[name]
if None in self.set_handlers:
return self.set_handlers[None]
raise KeyError(full_path_for_error)
raw_data_manager = ContentManager()
def get_text_content(msg, errors='replace'):
content = msg.get_payload(decode=True)
charset = msg.get_param('charset', 'ASCII')
return content.decode(charset, errors=errors)
raw_data_manager.add_get_handler('text', get_text_content)
def get_non_text_content(msg):
return msg.get_payload(decode=True)
for maintype in 'audio image video application'.split():
raw_data_manager.add_get_handler(maintype, get_non_text_content)
def get_message_content(msg):
return msg.get_payload(0)
for subtype in 'rfc822 external-body'.split():
raw_data_manager.add_get_handler('message/'+subtype, get_message_content)
def get_and_fixup_unknown_message_content(msg):
# If we don't understand a message subtype, we are supposed to treat it as
# if it were application/octet-stream, per
# tools.ietf.org/html/rfc2046#section-5.2.4. Feedparser doesn't do that,
# so do our best to fix things up. Note that it is *not* appropriate to
# model message/partial content as Message objects, so they are handled
# here as well. (How to reassemble them is out of scope for this comment :)
return bytes(msg.get_payload(0))
raw_data_manager.add_get_handler('message',
get_and_fixup_unknown_message_content)
def _prepare_set(msg, maintype, subtype, headers):
msg['Content-Type'] = '/'.join((maintype, subtype))
if headers:
if not hasattr(headers[0], 'name'):
mp = msg.policy
headers = [mp.header_factory(*mp.header_source_parse([header]))
for header in headers]
try:
for header in headers:
if header.defects:
raise header.defects[0]
msg[header.name] = header
except email.errors.HeaderDefect as exc:
raise ValueError("Invalid header: {}".format(
header.fold(policy=msg.policy))) from exc
def _finalize_set(msg, disposition, filename, cid, params):
if disposition is None and filename is not None:
disposition = 'attachment'
if disposition is not None:
msg['Content-Disposition'] = disposition
if filename is not None:
msg.set_param('filename',
filename,
header='Content-Disposition',
replace=True)
if cid is not None:
msg['Content-ID'] = cid
if params is not None:
for key, value in params.items():
msg.set_param(key, value)
# XXX: This is a cleaned-up version of base64mime.body_encode (including a bug
# fix in the calculation of unencoded_bytes_per_line). It would be nice to
# drop both this and quoprimime.body_encode in favor of enhanced binascii
# routines that accepted a max_line_length parameter.
def _encode_base64(data, max_line_length):
encoded_lines = []
unencoded_bytes_per_line = max_line_length // 4 * 3
for i in range(0, len(data), unencoded_bytes_per_line):
thisline = data[i:i+unencoded_bytes_per_line]
encoded_lines.append(binascii.b2a_base64(thisline).decode('ascii'))
return ''.join(encoded_lines)
def _encode_text(string, charset, cte, policy):
lines = string.encode(charset).splitlines()
linesep = policy.linesep.encode('ascii')
def embedded_body(lines): return linesep.join(lines) + linesep
def normal_body(lines): return b'\n'.join(lines) + b'\n'
if cte is None:
# Use heuristics to decide on the "best" encoding.
if max((len(x) for x in lines), default=0) <= policy.max_line_length:
try:
return '7bit', normal_body(lines).decode('ascii')
except UnicodeDecodeError:
pass
if policy.cte_type == '8bit':
return '8bit', normal_body(lines).decode('ascii', 'surrogateescape')
sniff = embedded_body(lines[:10])
sniff_qp = quoprimime.body_encode(sniff.decode('latin-1'),
policy.max_line_length)
sniff_base64 = binascii.b2a_base64(sniff)
# This is a little unfair to qp; it includes lineseps, base64 doesn't.
if len(sniff_qp) > len(sniff_base64):
cte = 'base64'
else:
cte = 'quoted-printable'
if len(lines) <= 10:
return cte, sniff_qp
if cte == '7bit':
data = normal_body(lines).decode('ascii')
elif cte == '8bit':
data = normal_body(lines).decode('ascii', 'surrogateescape')
elif cte == 'quoted-printable':
data = quoprimime.body_encode(normal_body(lines).decode('latin-1'),
policy.max_line_length)
elif cte == 'base64':
data = _encode_base64(embedded_body(lines), policy.max_line_length)
else:
raise ValueError("Unknown content transfer encoding {}".format(cte))
return cte, data
def set_text_content(msg, string, subtype="plain", charset='utf-8', cte=None,
disposition=None, filename=None, cid=None,
params=None, headers=None):
_prepare_set(msg, 'text', subtype, headers)
cte, payload = _encode_text(string, charset, cte, msg.policy)
msg.set_payload(payload)
msg.set_param('charset',
email.charset.ALIASES.get(charset, charset),
replace=True)
msg['Content-Transfer-Encoding'] = cte
_finalize_set(msg, disposition, filename, cid, params)
raw_data_manager.add_set_handler(str, set_text_content)
def set_message_content(msg, message, subtype="rfc822", cte=None,
disposition=None, filename=None, cid=None,
params=None, headers=None):
if subtype == 'partial':
raise ValueError("message/partial is not supported for Message objects")
if subtype == 'rfc822':
if cte not in (None, '7bit', '8bit', 'binary'):
# http://tools.ietf.org/html/rfc2046#section-5.2.1 mandate.
raise ValueError(
"message/rfc822 parts do not support cte={}".format(cte))
# 8bit will get coerced on serialization if policy.cte_type='7bit'. We
# may end up claiming 8bit when it isn't needed, but the only negative
# result of that should be a gateway that needs to coerce to 7bit
# having to look through the whole embedded message to discover whether
# or not it actually has to do anything.
cte = '8bit' if cte is None else cte
elif subtype == 'external-body':
if cte not in (None, '7bit'):
# http://tools.ietf.org/html/rfc2046#section-5.2.3 mandate.
raise ValueError(
"message/external-body parts do not support cte={}".format(cte))
cte = '7bit'
elif cte is None:
# http://tools.ietf.org/html/rfc2046#section-5.2.4 says all future
# subtypes should be restricted to 7bit, so assume that.
cte = '7bit'
_prepare_set(msg, 'message', subtype, headers)
msg.set_payload([message])
msg['Content-Transfer-Encoding'] = cte
_finalize_set(msg, disposition, filename, cid, params)
raw_data_manager.add_set_handler(email.message.Message, set_message_content)
def set_bytes_content(msg, data, maintype, subtype, cte='base64',
disposition=None, filename=None, cid=None,
params=None, headers=None):
_prepare_set(msg, maintype, subtype, headers)
if cte == 'base64':
data = _encode_base64(data, max_line_length=msg.policy.max_line_length)
elif cte == 'quoted-printable':
# XXX: quoprimime.body_encode won't encode newline characters in data,
# so we can't use it. This means max_line_length is ignored. Another
# bug to fix later. (Note: encoders.quopri is broken on line ends.)
data = binascii.b2a_qp(data, istext=False, header=False, quotetabs=True)
data = data.decode('ascii')
elif cte == '7bit':
data = data.decode('ascii')
elif cte in ('8bit', 'binary'):
data = data.decode('ascii', 'surrogateescape')
msg.set_payload(data)
msg['Content-Transfer-Encoding'] = cte
_finalize_set(msg, disposition, filename, cid, params)
for typ in (bytes, bytearray, memoryview):
raw_data_manager.add_set_handler(typ, set_bytes_content)
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