1 """HTTP server base class. 2 3 Note: the class in this module doesn't implement any HTTP request; see 4 SimpleHTTPServer for simple implementations of GET, HEAD and POST 5 (including CGI scripts). It does, however, optionally implement HTTP/1.1 6 persistent connections, as of version 0.3. 7 8 Contents: 9 10 - BaseHTTPRequestHandler: HTTP request handler base class 11 - test: test function 12 13 XXX To do: 14 15 - log requests even later (to capture byte count) 16 - log user-agent header and other interesting goodies 17 - send error log to separate file 18 """ 19 20 21 # See also: 22 # 23 # HTTP Working Group T. Berners-Lee 24 # INTERNET-DRAFT R. T. Fielding 25 # <draft-ietf-http-v10-spec-00.txt> H. Frystyk Nielsen 26 # Expires September 8, 1995 March 8, 1995 27 # 28 # URL: http://www.ics.uci.edu/pub/ietf/http/draft-ietf-http-v10-spec-00.txt 29 # 30 # and 31 # 32 # Network Working Group R. Fielding 33 # Request for Comments: 2616 et al 34 # Obsoletes: 2068 June 1999 35 # Category: Standards Track 36 # 37 # URL: http://www.faqs.org/rfcs/rfc2616.html 38 39 # Log files 40 # --------- 41 # 42 # Here's a quote from the NCSA httpd docs about log file format. 43 # 44 # | The logfile format is as follows. Each line consists of: 45 # | 46 # | host rfc931 authuser [DD/Mon/YYYY:hh:mm:ss] "request" ddd bbbb 47 # | 48 # | host: Either the DNS name or the IP number of the remote client 49 # | rfc931: Any information returned by identd for this person, 50 # | - otherwise. 51 # | authuser: If user sent a userid for authentication, the user name, 52 # | - otherwise. 53 # | DD: Day 54 # | Mon: Month (calendar name) 55 # | YYYY: Year 56 # | hh: hour (24-hour format, the machine's timezone) 57 # | mm: minutes 58 # | ss: seconds 59 # | request: The first line of the HTTP request as sent by the client. 60 # | ddd: the status code returned by the server, - if not available. 61 # | bbbb: the total number of bytes sent, 62 # | *not including the HTTP/1.0 header*, - if not available 63 # | 64 # | You can determine the name of the file accessed through request. 65 # 66 # (Actually, the latter is only true if you know the server configuration 67 # at the time the request was made!) 68 69 __version__ = "0.3" 70 71 __all__ = ["HTTPServer", "BaseHTTPRequestHandler"] 72 73 import sys 74 import time 75 import socket # For gethostbyaddr() 76 from warnings import filterwarnings, catch_warnings 77 with catch_warnings(): 78 if sys.py3kwarning: 79 filterwarnings("ignore", ".*mimetools has been removed", 80 DeprecationWarning) 81 import mimetools 82 import SocketServer 83 84 # Default error message template 85 DEFAULT_ERROR_MESSAGE = """\ 86 <head> 87 <title>Error response</title> 88 </head> 89 <body> 90 <h1>Error response</h1> 91 <p>Error code %(code)d. 92 <p>Message: %(message)s. 93 <p>Error code explanation: %(code)s = %(explain)s. 94 </body> 95 """ 96 97 DEFAULT_ERROR_CONTENT_TYPE = "text/html" 98 99 def _quote_html(html): 100 return html.replace("&", "&").replace("<", "<").replace(">", ">") 101 102 class HTTPServer(SocketServer.TCPServer): 103 104 allow_reuse_address = 1 # Seems to make sense in testing environment 105 106 def server_bind(self): 107 """Override server_bind to store the server name.""" 108 SocketServer.TCPServer.server_bind(self) 109 host, port = self.socket.getsockname()[:2] 110 self.server_name = socket.getfqdn(host) 111 self.server_port = port 112 113 114 class BaseHTTPRequestHandler(SocketServer.StreamRequestHandler): 115 116 """HTTP request handler base class. 117 118 The following explanation of HTTP serves to guide you through the 119 code as well as to expose any misunderstandings I may have about 120 HTTP (so you don't need to read the code to figure out I'm wrong 121 :-). 122 123 HTTP (HyperText Transfer Protocol) is an extensible protocol on 124 top of a reliable stream transport (e.g. TCP/IP). The protocol 125 recognizes three parts to a request: 126 127 1. One line identifying the request type and path 128 2. An optional set of RFC-822-style headers 129 3. An optional data part 130 131 The headers and data are separated by a blank line. 132 133 The first line of the request has the form 134 135 <command> <path> <version> 136 137 where <command> is a (case-sensitive) keyword such as GET or POST, 138 <path> is a string containing path information for the request, 139 and <version> should be the string "HTTP/1.0" or "HTTP/1.1". 140 <path> is encoded using the URL encoding scheme (using %xx to signify 141 the ASCII character with hex code xx). 142 143 The specification specifies that lines are separated by CRLF but 144 for compatibility with the widest range of clients recommends 145 servers also handle LF. Similarly, whitespace in the request line 146 is treated sensibly (allowing multiple spaces between components 147 and allowing trailing whitespace). 148 149 Similarly, for output, lines ought to be separated by CRLF pairs 150 but most clients grok LF characters just fine. 151 152 If the first line of the request has the form 153 154 <command> <path> 155 156 (i.e. <version> is left out) then this is assumed to be an HTTP 157 0.9 request; this form has no optional headers and data part and 158 the reply consists of just the data. 159 160 The reply form of the HTTP 1.x protocol again has three parts: 161 162 1. One line giving the response code 163 2. An optional set of RFC-822-style headers 164 3. The data 165 166 Again, the headers and data are separated by a blank line. 167 168 The response code line has the form 169 170 <version> <responsecode> <responsestring> 171 172 where <version> is the protocol version ("HTTP/1.0" or "HTTP/1.1"), 173 <responsecode> is a 3-digit response code indicating success or 174 failure of the request, and <responsestring> is an optional 175 human-readable string explaining what the response code means. 176 177 This server parses the request and the headers, and then calls a 178 function specific to the request type (<command>). Specifically, 179 a request SPAM will be handled by a method do_SPAM(). If no 180 such method exists the server sends an error response to the 181 client. If it exists, it is called with no arguments: 182 183 do_SPAM() 184 185 Note that the request name is case sensitive (i.e. SPAM and spam 186 are different requests). 187 188 The various request details are stored in instance variables: 189 190 - client_address is the client IP address in the form (host, 191 port); 192 193 - command, path and version are the broken-down request line; 194 195 - headers is an instance of mimetools.Message (or a derived 196 class) containing the header information; 197 198 - rfile is a file object open for reading positioned at the 199 start of the optional input data part; 200 201 - wfile is a file object open for writing. 202 203 IT IS IMPORTANT TO ADHERE TO THE PROTOCOL FOR WRITING! 204 205 The first thing to be written must be the response line. Then 206 follow 0 or more header lines, then a blank line, and then the 207 actual data (if any). The meaning of the header lines depends on 208 the command executed by the server; in most cases, when data is 209 returned, there should be at least one header line of the form 210 211 Content-type: <type>/<subtype> 212 213 where <type> and <subtype> should be registered MIME types, 214 e.g. "text/html" or "text/plain". 215 216 """ 217 218 # The Python system version, truncated to its first component. 219 sys_version = "Python/" + sys.version.split()[0] 220 221 # The server software version. You may want to override this. 222 # The format is multiple whitespace-separated strings, 223 # where each string is of the form name[/version]. 224 server_version = "BaseHTTP/" + __version__ 225 226 # The default request version. This only affects responses up until 227 # the point where the request line is parsed, so it mainly decides what 228 # the client gets back when sending a malformed request line. 229 # Most web servers default to HTTP 0.9, i.e. don't send a status line. 230 default_request_version = "HTTP/0.9" 231 232 def parse_request(self): 233 """Parse a request (internal). 234 235 The request should be stored in self.raw_requestline; the results 236 are in self.command, self.path, self.request_version and 237 self.headers. 238 239 Return True for success, False for failure; on failure, an 240 error is sent back. 241 242 """ 243 self.command = None # set in case of error on the first line 244 self.request_version = version = self.default_request_version 245 self.close_connection = 1 246 requestline = self.raw_requestline 247 if requestline[-2:] == '\r\n': 248 requestline = requestline[:-2] 249 elif requestline[-1:] == '\n': 250 requestline = requestline[:-1] 251 self.requestline = requestline 252 words = requestline.split() 253 if len(words) == 3: 254 [command, path, version] = words 255 if version[:5] != 'HTTP/': 256 self.send_error(400, "Bad request version (%r)" % version) 257 return False 258 try: 259 base_version_number = version.split('/', 1)[1] 260 version_number = base_version_number.split(".") 261 # RFC 2145 section 3.1 says there can be only one "." and 262 # - major and minor numbers MUST be treated as 263 # separate integers; 264 # - HTTP/2.4 is a lower version than HTTP/2.13, which in 265 # turn is lower than HTTP/12.3; 266 # - Leading zeros MUST be ignored by recipients. 267 if len(version_number) != 2: 268 raise ValueError 269 version_number = int(version_number[0]), int(version_number[1]) 270 except (ValueError, IndexError): 271 self.send_error(400, "Bad request version (%r)" % version) 272 return False 273 if version_number >= (1, 1) and self.protocol_version >= "HTTP/1.1": 274 self.close_connection = 0 275 if version_number >= (2, 0): 276 self.send_error(505, 277 "Invalid HTTP Version (%s)" % base_version_number) 278 return False 279 elif len(words) == 2: 280 [command, path] = words 281 self.close_connection = 1 282 if command != 'GET': 283 self.send_error(400, 284 "Bad HTTP/0.9 request type (%r)" % command) 285 return False 286 elif not words: 287 return False 288 else: 289 self.send_error(400, "Bad request syntax (%r)" % requestline) 290 return False 291 self.command, self.path, self.request_version = command, path, version 292 293 # Examine the headers and look for a Connection directive 294 self.headers = self.MessageClass(self.rfile, 0) 295 296 conntype = self.headers.get('Connection', "") 297 if conntype.lower() == 'close': 298 self.close_connection = 1 299 elif (conntype.lower() == 'keep-alive' and 300 self.protocol_version >= "HTTP/1.1"): 301 self.close_connection = 0 302 return True 303 304 def handle_one_request(self): 305 """Handle a single HTTP request. 306 307 You normally don't need to override this method; see the class 308 __doc__ string for information on how to handle specific HTTP 309 commands such as GET and POST. 310 311 """ 312 try: 313 self.raw_requestline = self.rfile.readline(65537) 314 if len(self.raw_requestline) > 65536: 315 self.requestline = '' 316 self.request_version = '' 317 self.command = '' 318 self.send_error(414) 319 return 320 if not self.raw_requestline: 321 self.close_connection = 1 322 return 323 if not self.parse_request(): 324 # An error code has been sent, just exit 325 return 326 mname = 'do_' + self.command 327 if not hasattr(self, mname): 328 self.send_error(501, "Unsupported method (%r)" % self.command) 329 return 330 method = getattr(self, mname) 331 method() 332 self.wfile.flush() #actually send the response if not already done. 333 except socket.timeout, e: 334 #a read or a write timed out. Discard this connection 335 self.log_error("Request timed out: %r", e) 336 self.close_connection = 1 337 return 338 339 def handle(self): 340 """Handle multiple requests if necessary.""" 341 self.close_connection = 1 342 343 self.handle_one_request() 344 while not self.close_connection: 345 self.handle_one_request() 346 347 def send_error(self, code, message=None): 348 """Send and log an error reply. 349 350 Arguments are the error code, and a detailed message. 351 The detailed message defaults to the short entry matching the 352 response code. 353 354 This sends an error response (so it must be called before any 355 output has been generated), logs the error, and finally sends 356 a piece of HTML explaining the error to the user. 357 358 """ 359 360 try: 361 short, long = self.responses[code] 362 except KeyError: 363 short, long = '???', '???' 364 if message is None: 365 message = short 366 explain = long 367 self.log_error("code %d, message %s", code, message) 368 # using _quote_html to prevent Cross Site Scripting attacks (see bug #1100201) 369 content = (self.error_message_format % 370 {'code': code, 'message': _quote_html(message), 'explain': explain}) 371 self.send_response(code, message) 372 self.send_header("Content-Type", self.error_content_type) 373 self.send_header('Connection', 'close') 374 self.end_headers() 375 if self.command != 'HEAD' and code >= 200 and code not in (204, 304): 376 self.wfile.write(content) 377 378 error_message_format = DEFAULT_ERROR_MESSAGE 379 error_content_type = DEFAULT_ERROR_CONTENT_TYPE 380 381 def send_response(self, code, message=None): 382 """Send the response header and log the response code. 383 384 Also send two standard headers with the server software 385 version and the current date. 386 387 """ 388 self.log_request(code) 389 if message is None: 390 if code in self.responses: 391 message = self.responses[code][0] 392 else: 393 message = '' 394 if self.request_version != 'HTTP/0.9': 395 self.wfile.write("%s %d %s\r\n" % 396 (self.protocol_version, code, message)) 397 # print (self.protocol_version, code, message) 398 self.send_header('Server', self.version_string()) 399 self.send_header('Date', self.date_time_string()) 400 401 def send_header(self, keyword, value): 402 """Send a MIME header.""" 403 if self.request_version != 'HTTP/0.9': 404 self.wfile.write("%s: %s\r\n" % (keyword, value)) 405 406 if keyword.lower() == 'connection': 407 if value.lower() == 'close': 408 self.close_connection = 1 409 elif value.lower() == 'keep-alive': 410 self.close_connection = 0 411 412 def end_headers(self): 413 """Send the blank line ending the MIME headers.""" 414 if self.request_version != 'HTTP/0.9': 415 self.wfile.write("\r\n") 416 417 def log_request(self, code='-', size='-'): 418 """Log an accepted request. 419 420 This is called by send_response(). 421 422 """ 423 424 self.log_message('"%s" %s %s', 425 self.requestline, str(code), str(size)) 426 427 def log_error(self, format, *args): 428 """Log an error. 429 430 This is called when a request cannot be fulfilled. By 431 default it passes the message on to log_message(). 432 433 Arguments are the same as for log_message(). 434 435 XXX This should go to the separate error log. 436 437 """ 438 439 self.log_message(format, *args) 440 441 def log_message(self, format, *args): 442 """Log an arbitrary message. 443 444 This is used by all other logging functions. Override 445 it if you have specific logging wishes. 446 447 The first argument, FORMAT, is a format string for the 448 message to be logged. If the format string contains 449 any % escapes requiring parameters, they should be 450 specified as subsequent arguments (it's just like 451 printf!). 452 453 The client host and current date/time are prefixed to 454 every message. 455 456 """ 457 458 sys.stderr.write("%s - - [%s] %s\n" % 459 (self.address_string(), 460 self.log_date_time_string(), 461 format%args)) 462 463 def version_string(self): 464 """Return the server software version string.""" 465 return self.server_version + ' ' + self.sys_version 466 467 def date_time_string(self, timestamp=None): 468 """Return the current date and time formatted for a message header.""" 469 if timestamp is None: 470 timestamp = time.time() 471 year, month, day, hh, mm, ss, wd, y, z = time.gmtime(timestamp) 472 s = "%s, %02d %3s %4d %02d:%02d:%02d GMT" % ( 473 self.weekdayname[wd], 474 day, self.monthname[month], year, 475 hh, mm, ss) 476 return s 477 478 def log_date_time_string(self): 479 """Return the current time formatted for logging.""" 480 now = time.time() 481 year, month, day, hh, mm, ss, x, y, z = time.localtime(now) 482 s = "%02d/%3s/%04d %02d:%02d:%02d" % ( 483 day, self.monthname[month], year, hh, mm, ss) 484 return s 485 486 weekdayname = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'] 487 488 monthname = [None, 489 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 490 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] 491 492 def address_string(self): 493 """Return the client address formatted for logging. 494 495 This version looks up the full hostname using gethostbyaddr(), 496 and tries to find a name that contains at least one dot. 497 498 """ 499 500 host, port = self.client_address[:2] 501 return socket.getfqdn(host) 502 503 # Essentially static class variables 504 505 # The version of the HTTP protocol we support. 506 # Set this to HTTP/1.1 to enable automatic keepalive 507 protocol_version = "HTTP/1.0" 508 509 # The Message-like class used to parse headers 510 MessageClass = mimetools.Message 511 512 # Table mapping response codes to messages; entries have the 513 # form {code: (shortmessage, longmessage)}. 514 # See RFC 2616. 515 responses = { 516 100: ('Continue', 'Request received, please continue'), 517 101: ('Switching Protocols', 518 'Switching to new protocol; obey Upgrade header'), 519 520 200: ('OK', 'Request fulfilled, document follows'), 521 201: ('Created', 'Document created, URL follows'), 522 202: ('Accepted', 523 'Request accepted, processing continues off-line'), 524 203: ('Non-Authoritative Information', 'Request fulfilled from cache'), 525 204: ('No Content', 'Request fulfilled, nothing follows'), 526 205: ('Reset Content', 'Clear input form for further input.'), 527 206: ('Partial Content', 'Partial content follows.'), 528 529 300: ('Multiple Choices', 530 'Object has several resources -- see URI list'), 531 301: ('Moved Permanently', 'Object moved permanently -- see URI list'), 532 302: ('Found', 'Object moved temporarily -- see URI list'), 533 303: ('See Other', 'Object moved -- see Method and URL list'), 534 304: ('Not Modified', 535 'Document has not changed since given time'), 536 305: ('Use Proxy', 537 'You must use proxy specified in Location to access this ' 538 'resource.'), 539 307: ('Temporary Redirect', 540 'Object moved temporarily -- see URI list'), 541 542 400: ('Bad Request', 543 'Bad request syntax or unsupported method'), 544 401: ('Unauthorized', 545 'No permission -- see authorization schemes'), 546 402: ('Payment Required', 547 'No payment -- see charging schemes'), 548 403: ('Forbidden', 549 'Request forbidden -- authorization will not help'), 550 404: ('Not Found', 'Nothing matches the given URI'), 551 405: ('Method Not Allowed', 552 'Specified method is invalid for this resource.'), 553 406: ('Not Acceptable', 'URI not available in preferred format.'), 554 407: ('Proxy Authentication Required', 'You must authenticate with ' 555 'this proxy before proceeding.'), 556 408: ('Request Timeout', 'Request timed out; try again later.'), 557 409: ('Conflict', 'Request conflict.'), 558 410: ('Gone', 559 'URI no longer exists and has been permanently removed.'), 560 411: ('Length Required', 'Client must specify Content-Length.'), 561 412: ('Precondition Failed', 'Precondition in headers is false.'), 562 413: ('Request Entity Too Large', 'Entity is too large.'), 563 414: ('Request-URI Too Long', 'URI is too long.'), 564 415: ('Unsupported Media Type', 'Entity body in unsupported format.'), 565 416: ('Requested Range Not Satisfiable', 566 'Cannot satisfy request range.'), 567 417: ('Expectation Failed', 568 'Expect condition could not be satisfied.'), 569 570 500: ('Internal Server Error', 'Server got itself in trouble'), 571 501: ('Not Implemented', 572 'Server does not support this operation'), 573 502: ('Bad Gateway', 'Invalid responses from another server/proxy.'), 574 503: ('Service Unavailable', 575 'The server cannot process the request due to a high load'), 576 504: ('Gateway Timeout', 577 'The gateway server did not receive a timely response'), 578 505: ('HTTP Version Not Supported', 'Cannot fulfill request.'), 579 } 580 581 582 def test(HandlerClass = BaseHTTPRequestHandler, 583 ServerClass = HTTPServer, protocol="HTTP/1.0"): 584 """Test the HTTP request handler class. 585 586 This runs an HTTP server on port 8000 (or the first command line 587 argument). 588 589 """ 590 591 if sys.argv[1:]: 592 port = int(sys.argv[1]) 593 else: 594 port = 8000 595 server_address = ('', port) 596 597 HandlerClass.protocol_version = protocol 598 httpd = ServerClass(server_address, HandlerClass) 599 600 sa = httpd.socket.getsockname() 601 print "Serving HTTP on", sa[0], "port", sa[1], "..." 602 httpd.serve_forever() 603 604 605 if __name__ == '__main__': 606 test() 607
