Lib/BaseHTTPServer.py

   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("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
 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()
 314             if not self.raw_requestline:
 315                 self.close_connection = 1
 316                 return
 317             if not self.parse_request():
 318                 # An error code has been sent, just exit
 319                 return
 320             mname = 'do_' + self.command
 321             if not hasattr(self, mname):
 322                 self.send_error(501, "Unsupported method (%r)" % self.command)
 323                 return
 324             method = getattr(self, mname)
 325             method()
 326             self.wfile.flush() #actually send the response if not already done.
 327         except socket.timeout, e:
 328             #a read or a write timed out.  Discard this connection
 329             self.log_error("Request timed out: %r", e)
 330             self.close_connection = 1
 331             return
 332
 333     def handle(self):
 334         """Handle multiple requests if necessary."""
 335         self.close_connection = 1
 336
 337         self.handle_one_request()
 338         while not self.close_connection:
 339             self.handle_one_request()
 340
 341     def send_error(self, code, message=None):
 342         """Send and log an error reply.
 343
 344         Arguments are the error code, and a detailed message.
 345         The detailed message defaults to the short entry matching the
 346         response code.
 347
 348         This sends an error response (so it must be called before any
 349         output has been generated), logs the error, and finally sends
 350         a piece of HTML explaining the error to the user.
 351
 352         """
 353
 354         try:
 355             short, long = self.responses[code]
 356         except KeyError:
 357             short, long = '???', '???'
 358         if message is None:
 359             message = short
 360         explain = long
 361         self.log_error("code %d, message %s", code, message)
 362         # using _quote_html to prevent Cross Site Scripting attacks (see bug #1100201)
 363         content = (self.error_message_format %
 364                    {'code': code, 'message': _quote_html(message), 'explain': explain})
 365         self.send_response(code, message)
 366         self.send_header("Content-Type", self.error_content_type)
 367         self.send_header('Connection', 'close')
 368         self.end_headers()
 369         if self.command != 'HEAD' and code >= 200 and code not in (204, 304):
 370             self.wfile.write(content)
 371
 372     error_message_format = DEFAULT_ERROR_MESSAGE
 373     error_content_type = DEFAULT_ERROR_CONTENT_TYPE
 374
 375     def send_response(self, code, message=None):
 376         """Send the response header and log the response code.
 377
 378         Also send two standard headers with the server software
 379         version and the current date.
 380
 381         """
 382         self.log_request(code)
 383         if message is None:
 384             if code in self.responses:
 385                 message = self.responses[code][0]
 386             else:
 387                 message = ''
 388         if self.request_version != 'HTTP/0.9':
 389             self.wfile.write("%s %d %s\r\n" %
 390                              (self.protocol_version, code, message))
 391             # print (self.protocol_version, code, message)
 392         self.send_header('Server', self.version_string())
 393         self.send_header('Date', self.date_time_string())
 394
 395     def send_header(self, keyword, value):
 396         """Send a MIME header."""
 397         if self.request_version != 'HTTP/0.9':
 398             self.wfile.write("%s: %s\r\n" % (keyword, value))
 399
 400         if keyword.lower() == 'connection':
 401             if value.lower() == 'close':
 402                 self.close_connection = 1
 403             elif value.lower() == 'keep-alive':
 404                 self.close_connection = 0
 405
 406     def end_headers(self):
 407         """Send the blank line ending the MIME headers."""
 408         if self.request_version != 'HTTP/0.9':
 409             self.wfile.write("\r\n")
 410
 411     def log_request(self, code='-', size='-'):
 412         """Log an accepted request.
 413
 414         This is called by send_response().
 415
 416         """
 417
 418         self.log_message('"%s" %s %s',
 419                          self.requestline, str(code), str(size))
 420
 421     def log_error(self, format, *args):
 422         """Log an error.
 423
 424         This is called when a request cannot be fulfilled.  By
 425         default it passes the message on to log_message().
 426
 427         Arguments are the same as for log_message().
 428
 429         XXX This should go to the separate error log.
 430
 431         """
 432
 433         self.log_message(format, *args)
 434
 435     def log_message(self, format, *args):
 436         """Log an arbitrary message.
 437
 438         This is used by all other logging functions.  Override
 439         it if you have specific logging wishes.
 440
 441         The first argument, FORMAT, is a format string for the
 442         message to be logged.  If the format string contains
 443         any % escapes requiring parameters, they should be
 444         specified as subsequent arguments (it's just like
 445         printf!).
 446
 447         The client host and current date/time are prefixed to
 448         every message.
 449
 450         """
 451
 452         sys.stderr.write("%s - - [%s] %s\n" %
 453                          (self.address_string(),
 454                           self.log_date_time_string(),
 455                           format%args))
 456
 457     def version_string(self):
 458         """Return the server software version string."""
 459         return self.server_version + ' ' + self.sys_version
 460
 461     def date_time_string(self, timestamp=None):
 462         """Return the current date and time formatted for a message header."""
 463         if timestamp is None:
 464             timestamp = time.time()
 465         year, month, day, hh, mm, ss, wd, y, z = time.gmtime(timestamp)
 466         s = "%s, %02d %3s %4d %02d:%02d:%02d GMT" % (
 467                 self.weekdayname[wd],
 468                 day, self.monthname[month], year,
 469                 hh, mm, ss)
 470         return s
 471
 472     def log_date_time_string(self):
 473         """Return the current time formatted for logging."""
 474         now = time.time()
 475         year, month, day, hh, mm, ss, x, y, z = time.localtime(now)
 476         s = "%02d/%3s/%04d %02d:%02d:%02d" % (
 477                 day, self.monthname[month], year, hh, mm, ss)
 478         return s
 479
 480     weekdayname = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
 481
 482     monthname = [None,
 483                  'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
 484                  'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
 485
 486     def address_string(self):
 487         """Return the client address formatted for logging.
 488
 489         This version looks up the full hostname using gethostbyaddr(),
 490         and tries to find a name that contains at least one dot.
 491
 492         """
 493
 494         host, port = self.client_address[:2]
 495         return socket.getfqdn(host)
 496
 497     # Essentially static class variables
 498
 499     # The version of the HTTP protocol we support.
 500     # Set this to HTTP/1.1 to enable automatic keepalive
 501     protocol_version = "HTTP/1.0"
 502
 503     # The Message-like class used to parse headers
 504     MessageClass = mimetools.Message
 505
 506     # Table mapping response codes to messages; entries have the
 507     # form {code: (shortmessage, longmessage)}.
 508     # See RFC 2616.
 509     responses = {
 510         100: ('Continue', 'Request received, please continue'),
 511         101: ('Switching Protocols',
 512               'Switching to new protocol; obey Upgrade header'),
 513
 514         200: ('OK', 'Request fulfilled, document follows'),
 515         201: ('Created', 'Document created, URL follows'),
 516         202: ('Accepted',
 517               'Request accepted, processing continues off-line'),
 518         203: ('Non-Authoritative Information', 'Request fulfilled from cache'),
 519         204: ('No Content', 'Request fulfilled, nothing follows'),
 520         205: ('Reset Content', 'Clear input form for further input.'),
 521         206: ('Partial Content', 'Partial content follows.'),
 522
 523         300: ('Multiple Choices',
 524               'Object has several resources -- see URI list'),
 525         301: ('Moved Permanently', 'Object moved permanently -- see URI list'),
 526         302: ('Found', 'Object moved temporarily -- see URI list'),
 527         303: ('See Other', 'Object moved -- see Method and URL list'),
 528         304: ('Not Modified',
 529               'Document has not changed since given time'),
 530         305: ('Use Proxy',
 531               'You must use proxy specified in Location to access this '
 532               'resource.'),
 533         307: ('Temporary Redirect',
 534               'Object moved temporarily -- see URI list'),
 535
 536         400: ('Bad Request',
 537               'Bad request syntax or unsupported method'),
 538         401: ('Unauthorized',
 539               'No permission -- see authorization schemes'),
 540         402: ('Payment Required',
 541               'No payment -- see charging schemes'),
 542         403: ('Forbidden',
 543               'Request forbidden -- authorization will not help'),
 544         404: ('Not Found', 'Nothing matches the given URI'),
 545         405: ('Method Not Allowed',
 546               'Specified method is invalid for this server.'),
 547         406: ('Not Acceptable', 'URI not available in preferred format.'),
 548         407: ('Proxy Authentication Required', 'You must authenticate with '
 549               'this proxy before proceeding.'),
 550         408: ('Request Timeout', 'Request timed out; try again later.'),
 551         409: ('Conflict', 'Request conflict.'),
 552         410: ('Gone',
 553               'URI no longer exists and has been permanently removed.'),
 554         411: ('Length Required', 'Client must specify Content-Length.'),
 555         412: ('Precondition Failed', 'Precondition in headers is false.'),
 556         413: ('Request Entity Too Large', 'Entity is too large.'),
 557         414: ('Request-URI Too Long', 'URI is too long.'),
 558         415: ('Unsupported Media Type', 'Entity body in unsupported format.'),
 559         416: ('Requested Range Not Satisfiable',
 560               'Cannot satisfy request range.'),
 561         417: ('Expectation Failed',
 562               'Expect condition could not be satisfied.'),
 563
 564         500: ('Internal Server Error', 'Server got itself in trouble'),
 565         501: ('Not Implemented',
 566               'Server does not support this operation'),
 567         502: ('Bad Gateway', 'Invalid responses from another server/proxy.'),
 568         503: ('Service Unavailable',
 569               'The server cannot process the request due to a high load'),
 570         504: ('Gateway Timeout',
 571               'The gateway server did not receive a timely response'),
 572         505: ('HTTP Version Not Supported', 'Cannot fulfill request.'),
 573         }
 574
 575
 576 def test(HandlerClass = BaseHTTPRequestHandler,
 577          ServerClass = HTTPServer, protocol="HTTP/1.0"):
 578     """Test the HTTP request handler class.
 579
 580     This runs an HTTP server on port 8000 (or the first command line
 581     argument).
 582
 583     """
 584
 585     if sys.argv[1:]:
 586         port = int(sys.argv[1])
 587     else:
 588         port = 8000
 589     server_address = ('', port)
 590
 591     HandlerClass.protocol_version = protocol
 592     httpd = ServerClass(server_address, HandlerClass)
 593
 594     sa = httpd.socket.getsockname()
 595     print "Serving HTTP on", sa[0], "port", sa[1], "..."
 596     httpd.serve_forever()
 597
 598
 599 if __name__ == '__main__':
 600     test()