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