1 #!/usr/bin/env python 2 3 """ 4 CGI classes. 5 6 Copyright (C) 2004, 2005, 2006 Paul Boddie <paul@boddie.org.uk> 7 8 This library is free software; you can redistribute it and/or 9 modify it under the terms of the GNU Lesser General Public 10 License as published by the Free Software Foundation; either 11 version 2.1 of the License, or (at your option) any later version. 12 13 This library is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 Lesser General Public License for more details. 17 18 You should have received a copy of the GNU Lesser General Public 19 License along with this library; if not, write to the Free Software 20 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA 21 """ 22 23 import WebStack.Generic 24 import os, sys 25 from WebStack.Helpers.Request import MessageBodyStream, get_body_fields, decode_value, get_storage_items, Cookie 26 from WebStack.Helpers.Response import ConvertingStream 27 from WebStack.Helpers.Auth import UserInfo 28 from WebStack.Helpers.Session import SessionStore 29 from WebStack.Helpers import Environment 30 from cgi import parse_qs, FieldStorage 31 from Cookie import SimpleCookie 32 from StringIO import StringIO 33 34 class Transaction(WebStack.Generic.Transaction): 35 36 """ 37 CGI transaction interface. 38 """ 39 40 def __init__(self, input=None, output=None, env=None): 41 42 """ 43 Initialise the transaction using the CGI 'input' and 'output' streams. 44 These streams are optional and default to standard input and standard 45 output respectively. 46 """ 47 48 self.input = input or sys.stdin 49 self.output = output or sys.stdout 50 self.env = env or os.environ 51 52 # Other attributes of interest in instances of this class. 53 54 self.content_type = None 55 self.response_code = 200 56 self.content = StringIO() 57 self.headers_out = {} 58 self.cookies_out = SimpleCookie() 59 60 # Define the incoming cookies. 61 62 self.cookies_in = SimpleCookie(self.env.get("HTTP_COOKIE")) 63 64 # Cached information. 65 66 self.storage_body = None 67 68 # Special objects retained throughout the transaction. 69 70 self.session_store = None 71 72 def commit(self): 73 74 """ 75 A special method, synchronising the transaction with framework-specific 76 objects. 77 78 See draft-coar-cgi-v11-03, section 7. 79 """ 80 81 # Close the session store. 82 83 if self.session_store is not None: 84 self.session_store.close() 85 86 # NOTE: Provide sensible messages. 87 88 self.output.write("Status: %s %s\n" % (self.response_code, "WebStack status")) 89 if self.content_type is not None: 90 self.output.write("Content-type: %s\n" % str(self.content_type)) 91 for header, value in self.headers_out.items(): 92 self.output.write("%s: %s\n" % 93 (self.format_header_value(header), self.format_header_value(value)) 94 ) 95 cookie_str = str(self.cookies_out) 96 if cookie_str: 97 self.output.write(cookie_str + "\n") 98 self.output.write("\n") 99 100 self.content.seek(0) 101 self.output.write(self.content.read()) 102 103 def rollback(self): 104 105 """ 106 A special method, partially synchronising the transaction with 107 framework-specific objects, but discarding previously emitted content 108 that is to be replaced by an error message. 109 """ 110 111 self.content = StringIO() 112 self.headers_out = {} 113 self.cookies_out = SimpleCookie() 114 115 # Server-related methods. 116 117 def get_server_name(self): 118 119 "Returns the server name." 120 121 return self.env.get("SERVER_NAME") 122 123 def get_server_port(self): 124 125 "Returns the server port as a string." 126 127 return self.env.get("SERVER_PORT") 128 129 # Request-related methods. 130 131 def get_request_stream(self): 132 133 """ 134 Returns the request stream for the transaction. 135 """ 136 137 return self.input 138 139 def get_request_method(self): 140 141 """ 142 Returns the request method. 143 """ 144 145 return self.env.get("REQUEST_METHOD") 146 147 def get_headers(self): 148 149 """ 150 Returns all request headers as a dictionary-like object mapping header 151 names to values. 152 """ 153 154 return Environment.get_headers(self.env) 155 156 def get_header_values(self, key): 157 158 """ 159 Returns a list of all request header values associated with the given 160 'key'. Note that according to RFC 2616, 'key' is treated as a 161 case-insensitive string. 162 """ 163 164 return self.convert_to_list(self.get_headers().get(key)) 165 166 def get_content_type(self): 167 168 """ 169 Returns the content type specified on the request, along with the 170 charset employed. 171 """ 172 173 return self.parse_content_type(self.env.get("CONTENT_TYPE")) 174 175 def get_content_charsets(self): 176 177 """ 178 Returns the character set preferences. 179 """ 180 181 return self.parse_content_preferences(self.get_headers().get("accept-charset")) 182 183 def get_content_languages(self): 184 185 """ 186 Returns extracted language information from the transaction. 187 """ 188 189 return self.parse_content_preferences(self.get_headers().get("accept-language")) 190 191 def get_path(self, encoding=None): 192 193 """ 194 Returns the entire path from the request as a Unicode object. Any "URL 195 encoded" character values in the part of the path before the query 196 string will be decoded and presented as genuine characters; the query 197 string will remain "URL encoded", however. 198 199 If the optional 'encoding' is set, use that in preference to the default 200 encoding to convert the path into a form not containing "URL encoded" 201 character values. 202 """ 203 204 path = self.get_path_without_query(encoding) 205 qs = self.get_query_string() 206 if qs: 207 return path + "?" + qs 208 else: 209 return path 210 211 def get_path_without_query(self, encoding=None): 212 213 """ 214 Returns the entire path from the request minus the query string as a 215 Unicode object containing genuine characters (as opposed to "URL 216 encoded" character values). 217 218 If the optional 'encoding' is set, use that in preference to the default 219 encoding to convert the path into a form not containing "URL encoded" 220 character values. 221 """ 222 223 path = decode_value(self.env.get("SCRIPT_NAME") or "", encoding) 224 path += self.get_path_info(encoding) 225 return path 226 227 def get_path_info(self, encoding=None): 228 229 """ 230 Returns the "path info" (the part of the URL after the resource name 231 handling the current request) from the request as a Unicode object 232 containing genuine characters (as opposed to "URL encoded" character 233 values). 234 235 If the optional 'encoding' is set, use that in preference to the default 236 encoding to convert the path into a form not containing "URL encoded" 237 character values. 238 """ 239 240 return decode_value(self.env.get("PATH_INFO") or "", encoding) 241 242 def get_query_string(self): 243 244 """ 245 Returns the query string from the path in the request. 246 """ 247 248 return self.env.get("QUERY_STRING") or "" 249 250 # Higher level request-related methods. 251 252 def get_fields_from_path(self, encoding=None): 253 254 """ 255 Extracts fields (or request parameters) from the path specified in the 256 transaction. The underlying framework may refuse to supply fields from 257 the path if handling a POST transaction. The optional 'encoding' 258 parameter specifies the character encoding of the query string for cases 259 where the default encoding is to be overridden. 260 261 Returns a dictionary mapping field names to lists of values (even if a 262 single value is associated with any given field name). 263 """ 264 265 fields = {} 266 for name, values in parse_qs(self.get_query_string(), keep_blank_values=1).items(): 267 name = decode_value(name, encoding) 268 fields[name] = [] 269 for value in values: 270 value = decode_value(value, encoding) 271 fields[name].append(value) 272 return fields 273 274 def get_fields_from_body(self, encoding=None): 275 276 """ 277 Extracts fields (or request parameters) from the message body in the 278 transaction. The optional 'encoding' parameter specifies the character 279 encoding of the message body for cases where no such information is 280 available, but where the default encoding is to be overridden. 281 282 Returns a dictionary mapping field names to lists of values (even if a 283 single value is associated with any given field name). Each value is 284 either a Unicode object (representing a simple form field, for example) 285 or a WebStack.Helpers.Request.FileContent object (representing a file 286 upload form field). 287 """ 288 289 encoding = encoding or self.get_content_type().charset or self.default_charset 290 291 if self.storage_body is None: 292 self.storage_body = FieldStorage(fp=self.get_request_stream(), 293 headers={"content-type" : str(self.get_content_type())}, 294 environ={"REQUEST_METHOD" : self.get_request_method()}, 295 keep_blank_values=1) 296 297 # Avoid strange design issues with FieldStorage by checking the internal 298 # field list directly. 299 300 fields = {} 301 if self.storage_body.list is not None: 302 303 # Traverse the storage, finding each field value. 304 305 fields = get_body_fields(get_storage_items(self.storage_body), encoding) 306 307 return fields 308 309 def get_fields(self, encoding=None): 310 311 """ 312 Extracts fields (or request parameters) from both the path specified in 313 the transaction as well as the message body. The optional 'encoding' 314 parameter specifies the character encoding of the message body for cases 315 where no such information is available, but where the default encoding 316 is to be overridden. 317 318 Returns a dictionary mapping field names to lists of values (even if a 319 single value is associated with any given field name). Each value is 320 either a Unicode object (representing a simple form field, for example) 321 or a WebStack.Helpers.Request.FileContent object (representing a file 322 upload form field). 323 324 Where a given field name is used in both the path and message body to 325 specify values, the values from both sources will be combined into a 326 single list associated with that field name. 327 """ 328 329 # Combine the two sources. 330 331 fields = {} 332 fields.update(self.get_fields_from_path()) 333 for name, values in self.get_fields_from_body(encoding).items(): 334 if not fields.has_key(name): 335 fields[name] = values 336 else: 337 fields[name] += values 338 return fields 339 340 def get_user(self): 341 342 """ 343 Extracts user information from the transaction. 344 345 Returns a username as a string or None if no user is defined. 346 """ 347 348 if self.user is not None: 349 return self.user 350 else: 351 return self.env.get("REMOTE_USER") 352 353 def get_cookies(self): 354 355 """ 356 Obtains cookie information from the request. 357 358 Returns a dictionary mapping cookie names to cookie objects. 359 """ 360 361 return self.process_cookies(self.cookies_in) 362 363 def get_cookie(self, cookie_name): 364 365 """ 366 Obtains cookie information from the request. 367 368 Returns a cookie object for the given 'cookie_name' or None if no such 369 cookie exists. 370 """ 371 372 cookie = self.cookies_in.get(self.encode_cookie_value(cookie_name)) 373 if cookie is not None: 374 return Cookie(cookie_name, self.decode_cookie_value(cookie.value)) 375 else: 376 return None 377 378 # Response-related methods. 379 380 def get_response_stream(self): 381 382 """ 383 Returns the response stream for the transaction. 384 """ 385 386 # Return a stream which is later emptied into the real stream. 387 # Unicode can upset this operation. Using either the specified charset 388 # or a default encoding. 389 390 encoding = self.get_response_stream_encoding() 391 return ConvertingStream(self.content, encoding) 392 393 def get_response_stream_encoding(self): 394 395 """ 396 Returns the response stream encoding. 397 """ 398 399 if self.content_type: 400 encoding = self.content_type.charset 401 else: 402 encoding = None 403 return encoding or self.default_charset 404 405 def get_response_code(self): 406 407 """ 408 Get the response code associated with the transaction. If no response 409 code is defined, None is returned. 410 """ 411 412 return self.response_code 413 414 def set_response_code(self, response_code): 415 416 """ 417 Set the 'response_code' using a numeric constant defined in the HTTP 418 specification. 419 """ 420 421 self.response_code = response_code 422 423 def set_header_value(self, header, value): 424 425 """ 426 Set the HTTP 'header' with the given 'value'. 427 """ 428 429 # The header is not written out immediately due to the buffering in use. 430 431 self.headers_out[header] = value 432 433 def set_content_type(self, content_type): 434 435 """ 436 Sets the 'content_type' for the response. 437 """ 438 439 # The content type has to be written as a header, before actual content, 440 # but after the response line. This means that some kind of buffering is 441 # required. Hence, we don't write the header out immediately. 442 443 self.content_type = content_type 444 445 # Higher level response-related methods. 446 447 def set_cookie(self, cookie): 448 449 """ 450 Stores the given 'cookie' object in the response. 451 """ 452 453 # NOTE: If multiple cookies of the same name could be specified, this 454 # NOTE: could need changing. 455 456 self.set_cookie_value(cookie.name, cookie.value) 457 458 def set_cookie_value(self, name, value, path=None, expires=None): 459 460 """ 461 Stores a cookie with the given 'name' and 'value' in the response. 462 463 The optional 'path' is a string which specifies the scope of the cookie, 464 and the optional 'expires' parameter is a value compatible with the 465 time.time function, and indicates the expiry date/time of the cookie. 466 """ 467 468 name = self.encode_cookie_value(name) 469 self.cookies_out[name] = self.encode_cookie_value(value) 470 if path is not None: 471 self.cookies_out[name]["path"] = path 472 if expires is not None: 473 self.cookies_out[name]["expires"] = expires 474 475 def delete_cookie(self, cookie_name): 476 477 """ 478 Adds to the response a request that the cookie with the given 479 'cookie_name' be deleted/discarded by the client. 480 """ 481 482 # Create a special cookie, given that we do not know whether the browser 483 # has been sent the cookie or not. 484 # NOTE: Magic discovered in Webware. 485 486 name = self.encode_cookie_value(cookie_name) 487 self.cookies_out[name] = "" 488 self.cookies_out[name]["path"] = "/" 489 self.cookies_out[name]["expires"] = 0 490 self.cookies_out[name]["max-age"] = 0 491 492 # Session-related methods. 493 494 def get_session(self, create=1): 495 496 """ 497 Gets a session corresponding to an identifier supplied in the 498 transaction. 499 500 If no session has yet been established according to information 501 provided in the transaction then the optional 'create' parameter 502 determines whether a new session will be established. 503 504 Where no session has been established and where 'create' is set to 0 505 then None is returned. In all other cases, a session object is created 506 (where appropriate) and returned. 507 """ 508 509 # NOTE: Requires configuration. 510 511 if self.session_store is None: 512 self.session_store = SessionStore(self, "WebStack-sessions") 513 return self.session_store.get_session(create) 514 515 def expire_session(self): 516 517 """ 518 Expires any session established according to information provided in the 519 transaction. 520 """ 521 522 # NOTE: Requires configuration. 523 524 if self.session_store is None: 525 self.session_store = SessionStore(self, "WebStack-sessions") 526 self.session_store.expire_session() 527 528 # vim: tabstop=4 expandtab shiftwidth=4