1############################################################################### 2# 3# The MIT License (MIT) 4# 5# Copyright (c) Crossbar.io Technologies GmbH 6# 7# Permission is hereby granted, free of charge, to any person obtaining a copy 8# of this software and associated documentation files (the "Software"), to deal 9# in the Software without restriction, including without limitation the rights 10# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 11# copies of the Software, and to permit persons to whom the Software is 12# furnished to do so, subject to the following conditions: 13# 14# The above copyright notice and this permission notice shall be included in 15# all copies or substantial portions of the Software. 16# 17# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 22# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 23# THE SOFTWARE. 24# 25############################################################################### 26 27from __future__ import absolute_import 28 29import snappy 30 31from autobahn.websocket.compress_base import PerMessageCompressOffer, \ 32 PerMessageCompressOfferAccept, \ 33 PerMessageCompressResponse, \ 34 PerMessageCompressResponseAccept, \ 35 PerMessageCompress 36 37__all__ = ( 38 'PerMessageSnappyMixin', 39 'PerMessageSnappyOffer', 40 'PerMessageSnappyOfferAccept', 41 'PerMessageSnappyResponse', 42 'PerMessageSnappyResponseAccept', 43 'PerMessageSnappy', 44) 45 46 47class PerMessageSnappyMixin(object): 48 """ 49 Mixin class for this extension. 50 """ 51 52 EXTENSION_NAME = "permessage-snappy" 53 """ 54 Name of this WebSocket extension. 55 """ 56 57 58class PerMessageSnappyOffer(PerMessageCompressOffer, PerMessageSnappyMixin): 59 """ 60 Set of extension parameters for `permessage-snappy` WebSocket extension 61 offered by a client to a server. 62 """ 63 64 @classmethod 65 def parse(cls, params): 66 """ 67 Parses a WebSocket extension offer for `permessage-snappy` provided by a client to a server. 68 69 :param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`. 70 :type params: list 71 72 :returns: A new instance of :class:`autobahn.compress.PerMessageSnappyOffer`. 73 :rtype: obj 74 """ 75 # extension parameter defaults 76 accept_no_context_takeover = False 77 request_no_context_takeover = False 78 79 # verify/parse client ("client-to-server direction") parameters of permessage-snappy offer 80 for p in params: 81 82 if len(params[p]) > 1: 83 raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) 84 85 val = params[p][0] 86 87 if p == 'client_no_context_takeover': 88 # noinspection PySimplifyBooleanCheck 89 if val is not True: 90 raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) 91 else: 92 accept_no_context_takeover = True 93 94 elif p == 'server_no_context_takeover': 95 # noinspection PySimplifyBooleanCheck 96 if val is not True: 97 raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) 98 else: 99 request_no_context_takeover = True 100 101 else: 102 raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) 103 104 offer = cls(accept_no_context_takeover, 105 request_no_context_takeover) 106 return offer 107 108 def __init__(self, 109 accept_no_context_takeover=True, 110 request_no_context_takeover=False): 111 """ 112 113 :param accept_no_context_takeover: Iff true, client accepts "no context takeover" feature. 114 :type accept_no_context_takeover: bool 115 :param request_no_context_takeover: Iff true, client request "no context takeover" feature. 116 :type request_no_context_takeover: bool 117 """ 118 if type(accept_no_context_takeover) != bool: 119 raise Exception("invalid type %s for accept_no_context_takeover" % type(accept_no_context_takeover)) 120 121 self.accept_no_context_takeover = accept_no_context_takeover 122 123 if type(request_no_context_takeover) != bool: 124 raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover)) 125 126 self.request_no_context_takeover = request_no_context_takeover 127 128 def get_extension_string(self): 129 """ 130 Returns the WebSocket extension configuration string as sent to the server. 131 132 :returns: PMCE configuration string. 133 :rtype: str 134 """ 135 pmce_string = self.EXTENSION_NAME 136 if self.accept_no_context_takeover: 137 pmce_string += "; client_no_context_takeover" 138 if self.request_no_context_takeover: 139 pmce_string += "; server_no_context_takeover" 140 return pmce_string 141 142 def __json__(self): 143 """ 144 Returns a JSON serializable object representation. 145 146 :returns: JSON serializable representation. 147 :rtype: dict 148 """ 149 return {'extension': self.EXTENSION_NAME, 150 'accept_no_context_takeover': self.accept_no_context_takeover, 151 'request_no_context_takeover': self.request_no_context_takeover} 152 153 def __repr__(self): 154 """ 155 Returns Python object representation that can be eval'ed to reconstruct the object. 156 157 :returns: Python string representation. 158 :rtype: str 159 """ 160 return "PerMessageSnappyOffer(accept_no_context_takeover = %s, request_no_context_takeover = %s)" % (self.accept_no_context_takeover, self.request_no_context_takeover) 161 162 163class PerMessageSnappyOfferAccept(PerMessageCompressOfferAccept, PerMessageSnappyMixin): 164 """ 165 Set of parameters with which to accept an `permessage-snappy` offer 166 from a client by a server. 167 """ 168 169 def __init__(self, 170 offer, 171 request_no_context_takeover=False, 172 no_context_takeover=None): 173 """ 174 175 :param offer: The offer being accepted. 176 :type offer: Instance of :class:`autobahn.compress.PerMessageSnappyOffer`. 177 :param request_no_context_takeover: Iff true, server request "no context takeover" feature. 178 :type request_no_context_takeover: bool 179 :param no_context_takeover: Override server ("server-to-client direction") context takeover (this must be compatible with offer). 180 :type no_context_takeover: bool 181 """ 182 if not isinstance(offer, PerMessageSnappyOffer): 183 raise Exception("invalid type %s for offer" % type(offer)) 184 185 self.offer = offer 186 187 if type(request_no_context_takeover) != bool: 188 raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover)) 189 190 if request_no_context_takeover and not offer.accept_no_context_takeover: 191 raise Exception("invalid value %s for request_no_context_takeover - feature unsupported by client" % request_no_context_takeover) 192 193 self.request_no_context_takeover = request_no_context_takeover 194 195 if no_context_takeover is not None: 196 if type(no_context_takeover) != bool: 197 raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover)) 198 199 if offer.request_no_context_takeover and not no_context_takeover: 200 raise Exception("invalid value %s for no_context_takeover - client requested feature" % no_context_takeover) 201 202 self.no_context_takeover = no_context_takeover 203 204 def get_extension_string(self): 205 """ 206 Returns the WebSocket extension configuration string as sent to the server. 207 208 :returns: PMCE configuration string. 209 :rtype: str 210 """ 211 pmce_string = self.EXTENSION_NAME 212 if self.offer.request_no_context_takeover: 213 pmce_string += "; server_no_context_takeover" 214 if self.request_no_context_takeover: 215 pmce_string += "; client_no_context_takeover" 216 return pmce_string 217 218 def __json__(self): 219 """ 220 Returns a JSON serializable object representation. 221 222 :returns: JSON serializable representation. 223 :rtype: dict 224 """ 225 return {'extension': self.EXTENSION_NAME, 226 'offer': self.offer.__json__(), 227 'request_no_context_takeover': self.request_no_context_takeover, 228 'no_context_takeover': self.no_context_takeover} 229 230 def __repr__(self): 231 """ 232 Returns Python object representation that can be eval'ed to reconstruct the object. 233 234 :returns: Python string representation. 235 :rtype: str 236 """ 237 return "PerMessageSnappyAccept(offer = %s, request_no_context_takeover = %s, no_context_takeover = %s)" % (self.offer.__repr__(), self.request_no_context_takeover, self.no_context_takeover) 238 239 240class PerMessageSnappyResponse(PerMessageCompressResponse, PerMessageSnappyMixin): 241 """ 242 Set of parameters for `permessage-snappy` responded by server. 243 """ 244 245 @classmethod 246 def parse(cls, params): 247 """ 248 Parses a WebSocket extension response for `permessage-snappy` provided by a server to a client. 249 250 :param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`. 251 :type params: list 252 253 :returns: A new instance of :class:`autobahn.compress.PerMessageSnappyResponse`. 254 :rtype: obj 255 """ 256 client_no_context_takeover = False 257 server_no_context_takeover = False 258 259 for p in params: 260 261 if len(params[p]) > 1: 262 raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) 263 264 val = params[p][0] 265 266 if p == 'client_no_context_takeover': 267 # noinspection PySimplifyBooleanCheck 268 if val is not True: 269 raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) 270 else: 271 client_no_context_takeover = True 272 273 elif p == 'server_no_context_takeover': 274 # noinspection PySimplifyBooleanCheck 275 if val is not True: 276 raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) 277 else: 278 server_no_context_takeover = True 279 280 else: 281 raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) 282 283 response = cls(client_no_context_takeover, 284 server_no_context_takeover) 285 return response 286 287 def __init__(self, 288 client_no_context_takeover, 289 server_no_context_takeover): 290 self.client_no_context_takeover = client_no_context_takeover 291 self.server_no_context_takeover = server_no_context_takeover 292 293 def __json__(self): 294 """ 295 Returns a JSON serializable object representation. 296 297 :returns: JSON serializable representation. 298 :rtype: dict 299 """ 300 return {'extension': self.EXTENSION_NAME, 301 'client_no_context_takeover': self.client_no_context_takeover, 302 'server_no_context_takeover': self.server_no_context_takeover} 303 304 def __repr__(self): 305 """ 306 Returns Python object representation that can be eval'ed to reconstruct the object. 307 308 :returns: Python string representation. 309 :rtype: str 310 """ 311 return "PerMessageSnappyResponse(client_no_context_takeover = %s, server_no_context_takeover = %s)" % (self.client_no_context_takeover, self.server_no_context_takeover) 312 313 314class PerMessageSnappyResponseAccept(PerMessageCompressResponseAccept, PerMessageSnappyMixin): 315 """ 316 Set of parameters with which to accept an `permessage-snappy` response 317 from a server by a client. 318 """ 319 320 def __init__(self, 321 response, 322 no_context_takeover=None): 323 """ 324 325 :param response: The response being accepted. 326 :type response: Instance of :class:`autobahn.compress.PerMessageSnappyResponse`. 327 :param no_context_takeover: Override client ("client-to-server direction") context takeover (this must be compatible with response). 328 :type no_context_takeover: bool 329 """ 330 if not isinstance(response, PerMessageSnappyResponse): 331 raise Exception("invalid type %s for response" % type(response)) 332 333 self.response = response 334 335 if no_context_takeover is not None: 336 if type(no_context_takeover) != bool: 337 raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover)) 338 339 if response.client_no_context_takeover and not no_context_takeover: 340 raise Exception("invalid value %s for no_context_takeover - server requested feature" % no_context_takeover) 341 342 self.no_context_takeover = no_context_takeover 343 344 def __json__(self): 345 """ 346 Returns a JSON serializable object representation. 347 348 :returns: JSON serializable representation. 349 :rtype: dict 350 """ 351 return {'extension': self.EXTENSION_NAME, 352 'response': self.response.__json__(), 353 'no_context_takeover': self.no_context_takeover} 354 355 def __repr__(self): 356 """ 357 Returns Python object representation that can be eval'ed to reconstruct the object. 358 359 :returns: Python string representation. 360 :rtype: str 361 """ 362 return "PerMessageSnappyResponseAccept(response = %s, no_context_takeover = %s)" % (self.response.__repr__(), self.no_context_takeover) 363 364 365class PerMessageSnappy(PerMessageCompress, PerMessageSnappyMixin): 366 """ 367 `permessage-snappy` WebSocket extension processor. 368 """ 369 370 @classmethod 371 def create_from_response_accept(cls, is_server, accept): 372 pmce = cls(is_server, 373 accept.response.server_no_context_takeover, 374 accept.no_context_takeover if accept.no_context_takeover is not None else accept.response.client_no_context_takeover) 375 return pmce 376 377 @classmethod 378 def create_from_offer_accept(cls, is_server, accept): 379 pmce = cls(is_server, 380 accept.no_context_takeover if accept.no_context_takeover is not None else accept.offer.request_no_context_takeover, 381 accept.request_no_context_takeover) 382 return pmce 383 384 def __init__(self, 385 is_server, 386 server_no_context_takeover, 387 client_no_context_takeover): 388 self._is_server = is_server 389 self.server_no_context_takeover = server_no_context_takeover 390 self.client_no_context_takeover = client_no_context_takeover 391 392 self._compressor = None 393 self._decompressor = None 394 395 def __json__(self): 396 return {'extension': self.EXTENSION_NAME, 397 'server_no_context_takeover': self.server_no_context_takeover, 398 'client_no_context_takeover': self.client_no_context_takeover} 399 400 def __repr__(self): 401 return "PerMessageSnappy(is_server = %s, server_no_context_takeover = %s, client_no_context_takeover = %s)" % (self._is_server, self.server_no_context_takeover, self.client_no_context_takeover) 402 403 def start_compress_message(self): 404 if self._is_server: 405 if self._compressor is None or self.server_no_context_takeover: 406 self._compressor = snappy.StreamCompressor() 407 else: 408 if self._compressor is None or self.client_no_context_takeover: 409 self._compressor = snappy.StreamCompressor() 410 411 def compress_message_data(self, data): 412 return self._compressor.add_chunk(data) 413 414 def end_compress_message(self): 415 return "" 416 417 def start_decompress_message(self): 418 if self._is_server: 419 if self._decompressor is None or self.client_no_context_takeover: 420 self._decompressor = snappy.StreamDecompressor() 421 else: 422 if self._decompressor is None or self.server_no_context_takeover: 423 self._decompressor = snappy.StreamDecompressor() 424 425 def decompress_message_data(self, data): 426 return self._decompressor.decompress(data) 427 428 def end_decompress_message(self): 429 pass 430