1import binascii 2import email.charset 3import email.message 4import email.errors 5from email import quoprimime 6 7class ContentManager: 8 9 def __init__(self): 10 self.get_handlers = {} 11 self.set_handlers = {} 12 13 def add_get_handler(self, key, handler): 14 self.get_handlers[key] = handler 15 16 def get_content(self, msg, *args, **kw): 17 content_type = msg.get_content_type() 18 if content_type in self.get_handlers: 19 return self.get_handlers[content_type](msg, *args, **kw) 20 maintype = msg.get_content_maintype() 21 if maintype in self.get_handlers: 22 return self.get_handlers[maintype](msg, *args, **kw) 23 if '' in self.get_handlers: 24 return self.get_handlers[''](msg, *args, **kw) 25 raise KeyError(content_type) 26 27 def add_set_handler(self, typekey, handler): 28 self.set_handlers[typekey] = handler 29 30 def set_content(self, msg, obj, *args, **kw): 31 if msg.get_content_maintype() == 'multipart': 32 # XXX: is this error a good idea or not? We can remove it later, 33 # but we can't add it later, so do it for now. 34 raise TypeError("set_content not valid on multipart") 35 handler = self._find_set_handler(msg, obj) 36 msg.clear_content() 37 handler(msg, obj, *args, **kw) 38 39 def _find_set_handler(self, msg, obj): 40 full_path_for_error = None 41 for typ in type(obj).__mro__: 42 if typ in self.set_handlers: 43 return self.set_handlers[typ] 44 qname = typ.__qualname__ 45 modname = getattr(typ, '__module__', '') 46 full_path = '.'.join((modname, qname)) if modname else qname 47 if full_path_for_error is None: 48 full_path_for_error = full_path 49 if full_path in self.set_handlers: 50 return self.set_handlers[full_path] 51 if qname in self.set_handlers: 52 return self.set_handlers[qname] 53 name = typ.__name__ 54 if name in self.set_handlers: 55 return self.set_handlers[name] 56 if None in self.set_handlers: 57 return self.set_handlers[None] 58 raise KeyError(full_path_for_error) 59 60 61raw_data_manager = ContentManager() 62 63 64def get_text_content(msg, errors='replace'): 65 content = msg.get_payload(decode=True) 66 charset = msg.get_param('charset', 'ASCII') 67 return content.decode(charset, errors=errors) 68raw_data_manager.add_get_handler('text', get_text_content) 69 70 71def get_non_text_content(msg): 72 return msg.get_payload(decode=True) 73for maintype in 'audio image video application'.split(): 74 raw_data_manager.add_get_handler(maintype, get_non_text_content) 75del maintype 76 77 78def get_message_content(msg): 79 return msg.get_payload(0) 80for subtype in 'rfc822 external-body'.split(): 81 raw_data_manager.add_get_handler('message/'+subtype, get_message_content) 82del subtype 83 84 85def get_and_fixup_unknown_message_content(msg): 86 # If we don't understand a message subtype, we are supposed to treat it as 87 # if it were application/octet-stream, per 88 # tools.ietf.org/html/rfc2046#section-5.2.4. Feedparser doesn't do that, 89 # so do our best to fix things up. Note that it is *not* appropriate to 90 # model message/partial content as Message objects, so they are handled 91 # here as well. (How to reassemble them is out of scope for this comment :) 92 return bytes(msg.get_payload(0)) 93raw_data_manager.add_get_handler('message', 94 get_and_fixup_unknown_message_content) 95 96 97def _prepare_set(msg, maintype, subtype, headers): 98 msg['Content-Type'] = '/'.join((maintype, subtype)) 99 if headers: 100 if not hasattr(headers[0], 'name'): 101 mp = msg.policy 102 headers = [mp.header_factory(*mp.header_source_parse([header])) 103 for header in headers] 104 try: 105 for header in headers: 106 if header.defects: 107 raise header.defects[0] 108 msg[header.name] = header 109 except email.errors.HeaderDefect as exc: 110 raise ValueError("Invalid header: {}".format( 111 header.fold(policy=msg.policy))) from exc 112 113 114def _finalize_set(msg, disposition, filename, cid, params): 115 if disposition is None and filename is not None: 116 disposition = 'attachment' 117 if disposition is not None: 118 msg['Content-Disposition'] = disposition 119 if filename is not None: 120 msg.set_param('filename', 121 filename, 122 header='Content-Disposition', 123 replace=True) 124 if cid is not None: 125 msg['Content-ID'] = cid 126 if params is not None: 127 for key, value in params.items(): 128 msg.set_param(key, value) 129 130 131# XXX: This is a cleaned-up version of base64mime.body_encode (including a bug 132# fix in the calculation of unencoded_bytes_per_line). It would be nice to 133# drop both this and quoprimime.body_encode in favor of enhanced binascii 134# routines that accepted a max_line_length parameter. 135def _encode_base64(data, max_line_length): 136 encoded_lines = [] 137 unencoded_bytes_per_line = max_line_length // 4 * 3 138 for i in range(0, len(data), unencoded_bytes_per_line): 139 thisline = data[i:i+unencoded_bytes_per_line] 140 encoded_lines.append(binascii.b2a_base64(thisline).decode('ascii')) 141 return ''.join(encoded_lines) 142 143 144def _encode_text(string, charset, cte, policy): 145 lines = string.encode(charset).splitlines() 146 linesep = policy.linesep.encode('ascii') 147 def embedded_body(lines): return linesep.join(lines) + linesep 148 def normal_body(lines): return b'\n'.join(lines) + b'\n' 149 if cte is None: 150 # Use heuristics to decide on the "best" encoding. 151 if max((len(x) for x in lines), default=0) <= policy.max_line_length: 152 try: 153 return '7bit', normal_body(lines).decode('ascii') 154 except UnicodeDecodeError: 155 pass 156 if policy.cte_type == '8bit': 157 return '8bit', normal_body(lines).decode('ascii', 'surrogateescape') 158 sniff = embedded_body(lines[:10]) 159 sniff_qp = quoprimime.body_encode(sniff.decode('latin-1'), 160 policy.max_line_length) 161 sniff_base64 = binascii.b2a_base64(sniff) 162 # This is a little unfair to qp; it includes lineseps, base64 doesn't. 163 if len(sniff_qp) > len(sniff_base64): 164 cte = 'base64' 165 else: 166 cte = 'quoted-printable' 167 if len(lines) <= 10: 168 return cte, sniff_qp 169 if cte == '7bit': 170 data = normal_body(lines).decode('ascii') 171 elif cte == '8bit': 172 data = normal_body(lines).decode('ascii', 'surrogateescape') 173 elif cte == 'quoted-printable': 174 data = quoprimime.body_encode(normal_body(lines).decode('latin-1'), 175 policy.max_line_length) 176 elif cte == 'base64': 177 data = _encode_base64(embedded_body(lines), policy.max_line_length) 178 else: 179 raise ValueError("Unknown content transfer encoding {}".format(cte)) 180 return cte, data 181 182 183def set_text_content(msg, string, subtype="plain", charset='utf-8', cte=None, 184 disposition=None, filename=None, cid=None, 185 params=None, headers=None): 186 _prepare_set(msg, 'text', subtype, headers) 187 cte, payload = _encode_text(string, charset, cte, msg.policy) 188 msg.set_payload(payload) 189 msg.set_param('charset', 190 email.charset.ALIASES.get(charset, charset), 191 replace=True) 192 msg['Content-Transfer-Encoding'] = cte 193 _finalize_set(msg, disposition, filename, cid, params) 194raw_data_manager.add_set_handler(str, set_text_content) 195 196 197def set_message_content(msg, message, subtype="rfc822", cte=None, 198 disposition=None, filename=None, cid=None, 199 params=None, headers=None): 200 if subtype == 'partial': 201 raise ValueError("message/partial is not supported for Message objects") 202 if subtype == 'rfc822': 203 if cte not in (None, '7bit', '8bit', 'binary'): 204 # http://tools.ietf.org/html/rfc2046#section-5.2.1 mandate. 205 raise ValueError( 206 "message/rfc822 parts do not support cte={}".format(cte)) 207 # 8bit will get coerced on serialization if policy.cte_type='7bit'. We 208 # may end up claiming 8bit when it isn't needed, but the only negative 209 # result of that should be a gateway that needs to coerce to 7bit 210 # having to look through the whole embedded message to discover whether 211 # or not it actually has to do anything. 212 cte = '8bit' if cte is None else cte 213 elif subtype == 'external-body': 214 if cte not in (None, '7bit'): 215 # http://tools.ietf.org/html/rfc2046#section-5.2.3 mandate. 216 raise ValueError( 217 "message/external-body parts do not support cte={}".format(cte)) 218 cte = '7bit' 219 elif cte is None: 220 # http://tools.ietf.org/html/rfc2046#section-5.2.4 says all future 221 # subtypes should be restricted to 7bit, so assume that. 222 cte = '7bit' 223 _prepare_set(msg, 'message', subtype, headers) 224 msg.set_payload([message]) 225 msg['Content-Transfer-Encoding'] = cte 226 _finalize_set(msg, disposition, filename, cid, params) 227raw_data_manager.add_set_handler(email.message.Message, set_message_content) 228 229 230def set_bytes_content(msg, data, maintype, subtype, cte='base64', 231 disposition=None, filename=None, cid=None, 232 params=None, headers=None): 233 _prepare_set(msg, maintype, subtype, headers) 234 if cte == 'base64': 235 data = _encode_base64(data, max_line_length=msg.policy.max_line_length) 236 elif cte == 'quoted-printable': 237 # XXX: quoprimime.body_encode won't encode newline characters in data, 238 # so we can't use it. This means max_line_length is ignored. Another 239 # bug to fix later. (Note: encoders.quopri is broken on line ends.) 240 data = binascii.b2a_qp(data, istext=False, header=False, quotetabs=True) 241 data = data.decode('ascii') 242 elif cte == '7bit': 243 data = data.decode('ascii') 244 elif cte in ('8bit', 'binary'): 245 data = data.decode('ascii', 'surrogateescape') 246 msg.set_payload(data) 247 msg['Content-Transfer-Encoding'] = cte 248 _finalize_set(msg, disposition, filename, cid, params) 249for typ in (bytes, bytearray, memoryview): 250 raw_data_manager.add_set_handler(typ, set_bytes_content) 251del typ 252