"""HTTP server base class. Note: the class in this module doesn't implement any HTTP request; see SimpleHTTPServer for simple implementations of GET, HEAD and POST (including CGI scripts). Contents: - BaseHTTPRequestHandler: HTTP request handler base class - test: test function XXX To do: - send server version - log requests even later (to capture byte count) - log user-agent header and other interesting goodies - send error log to separate file - are request names really case sensitive? """ # See also: # # HTTP Working Group T. Berners-Lee # INTERNET-DRAFT R. T. Fielding # H. Frystyk Nielsen # Expires September 8, 1995 March 8, 1995 # # URL: http://www.ics.uci.edu/pub/ietf/http/draft-ietf-http-v10-spec-00.txt # Log files # --------- # # Here's a quote from the NCSA httpd docs about log file format. # # | The logfile format is as follows. Each line consists of: # | # | host rfc931 authuser [DD/Mon/YYYY:hh:mm:ss] "request" ddd bbbb # | # | host: Either the DNS name or the IP number of the remote client # | rfc931: Any information returned by identd for this person, # | - otherwise. # | authuser: If user sent a userid for authentication, the user name, # | - otherwise. # | DD: Day # | Mon: Month (calendar name) # | YYYY: Year # | hh: hour (24-hour format, the machine's timezone) # | mm: minutes # | ss: seconds # | request: The first line of the HTTP request as sent by the client. # | ddd: the status code returned by the server, - if not available. # | bbbb: the total number of bytes sent, # | *not including the HTTP/1.0 header*, - if not available # | # | You can determine the name of the file accessed through request. # # (Actually, the latter is only true if you know the server configuration # at the time the request was made!) __version__ = "0.2" import sys import time import socket # For gethostbyaddr() import string import mimetools import SocketServer # Default error message DEFAULT_ERROR_MESSAGE = """\ Error response

Error response

Error code %(code)d.

Message: %(message)s.

Error code explanation: %(code)s = %(explain)s. """ class HTTPServer(SocketServer.TCPServer): def server_bind(self): """Override server_bind to store the server name.""" SocketServer.TCPServer.server_bind(self) host, port = self.socket.getsockname() if not host or host == '0.0.0.0': host = socket.gethostname() try: hostname, hostnames, hostaddrs = socket.gethostbyaddr(host) except socket.error: hostname = host else: if '.' not in hostname: for host in hostnames: if '.' in host: hostname = host break self.server_name = hostname self.server_port = port class BaseHTTPRequestHandler(SocketServer.StreamRequestHandler): """HTTP request handler base class. The following explanation of HTTP serves to guide you through the code as well as to expose any misunderstandings I may have about HTTP (so you don't need to read the code to figure out I'm wrong :-). HTTP (HyperText Transfer Protocol) is an extensible protocol on top of a reliable stream transport (e.g. TCP/IP). The protocol recognizes three parts to a request: 1. One line identifying the request type and path 2. An optional set of RFC-822-style headers 3. An optional data part The headers and data are separated by a blank line. The first line of the request has the form where is a (case-sensitive) keyword such as GET or POST, is a string containing path information for the request, and should be the string "HTTP/1.0". is encoded using the URL encoding scheme (using %xx to signify the ASCII character with hex code xx). The protocol is vague about whether lines are separated by LF characters or by CRLF pairs -- for compatibility with the widest range of clients, both should be accepted. Similarly, whitespace in the request line should be treated sensibly (allowing multiple spaces between components and allowing trailing whitespace). Similarly, for output, lines ought to be separated by CRLF pairs but most clients grok LF characters just fine. If the first line of the request has the form (i.e. is left out) then this is assumed to be an HTTP 0.9 request; this form has no optional headers and data part and the reply consists of just the data. The reply form of the HTTP 1.0 protocol again has three parts: 1. One line giving the response code 2. An optional set of RFC-822-style headers 3. The data Again, the headers and data are separated by a blank line. The response code line has the form where is the protocol version (always "HTTP/1.0"), is a 3-digit response code indicating success or failure of the request, and is an optional human-readable string explaining what the response code means. This server parses the request and the headers, and then calls a function specific to the request type (). Specifically, a request SPAM will be handled by a method handle_SPAM(). If no such method exists the server sends an error response to the client. If it exists, it is called with no arguments: do_SPAM() Note that the request name is case sensitive (i.e. SPAM and spam are different requests). The various request details are stored in instance variables: - client_address is the client IP address in the form (host, port); - command, path and version are the broken-down request line; - headers is an instance of mimetools.Message (or a derived class) containing the header information; - rfile is a file object open for reading positioned at the start of the optional input data part; - wfile is a file object open for writing. IT IS IMPORTANT TO ADHERE TO THE PROTOCOL FOR WRITING! The first thing to be written must be the response line. Then follow 0 or more header lines, then a blank line, and then the actual data (if any). The meaning of the header lines depends on the command executed by the server; in most cases, when data is returned, there should be at least one header line of the form Content-type: / where and should be registered MIME types, e.g. "text/html" or "text/plain". """ # The Python system version, truncated to its first component. sys_version = "Python/" + string.split(sys.version)[0] # The server software version. You may want to override this. # The format is multiple whitespace-separated strings, # where each string is of the form name[/version]. server_version = "BaseHTTP/" + __version__ def handle(self): """Handle a single HTTP request. You normally don't need to override this method; see the class __doc__ string for information on how to handle specific HTTP commands such as GET and POST. """ self.raw_requestline = self.rfile.readline() self.request_version = version = "HTTP/0.9" # Default requestline = self.raw_requestline if requestline[-2:] == '\r\n': requestline = requestline[:-2] elif requestline[-1:] == '\n': requestline = requestline[:-1] self.requestline = requestline words = string.split(requestline) if len(words) == 3: [command, path, version] = words if version[:5] != 'HTTP/': self.send_error(400, "Bad request version (%s)" % `version`) return elif len(words) == 2: [command, path] = words if command != 'GET': self.send_error(400, "Bad HTTP/0.9 request type (%s)" % `command`) return else: self.send_error(400, "Bad request syntax (%s)" % `requestline`) return self.command, self.path, self.request_version = command, path, version self.headers = self.MessageClass(self.rfile, 0) mname = 'do_' + command if not hasattr(self, mname): self.send_error(501, "Unsupported method (%s)" % `command`) return method = getattr(self, mname) method() def send_error(self, code, message=None): """Send and log an error reply. Arguments are the error code, and a detailed message. The detailed message defaults to the short entry matching the response code. This sends an error response (so it must be called before any output has been generated), logs the error, and finally sends a piece of HTML explaining the error to the user. """ try: short, long = self.responses[code] except KeyError: short, long = '???', '???' if not message: message = short explain = long self.log_error("code %d, message %s", code, message) self.send_response(code, message) self.end_headers() self.wfile.write(self.error_message_format % {'code': code, 'message': message, 'explain': explain}) error_message_format = DEFAULT_ERROR_MESSAGE def send_response(self, code, message=None): """Send the response header and log the response code. Also send two standard headers with the server software version and the current date. """ self.log_request(code) if message is None: if self.responses.has_key(code): message = self.responses[code][0] else: message = '' if self.request_version != 'HTTP/0.9': self.wfile.write("%s %s %s\r\n" % (self.protocol_version, str(code), message)) self.send_header('Server', self.version_string()) self.send_header('Date', self.date_time_string()) def send_header(self, keyword, value): """Send a MIME header.""" if self.request_version != 'HTTP/0.9': self.wfile.write("%s: %s\r\n" % (keyword, value)) def end_headers(self): """Send the blank line ending the MIME headers.""" if self.request_version != 'HTTP/0.9': self.wfile.write("\r\n") def log_request(self, code='-', size='-'): """Log an accepted request. This is called by send_reponse(). """ self.log_message('"%s" %s %s', self.requestline, str(code), str(size)) def log_error(self, *args): """Log an error. This is called when a request cannot be fulfilled. By default it passes the message on to log_message(). Arguments are the same as for log_message(). XXX This should go to the separate error log. """ apply(self.log_message, args) def log_message(self, format, *args): """Log an arbitrary message. This is used by all other logging functions. Override it if you have specific logging wishes. The first argument, FORMAT, is a format string for the message to be logged. If the format string contains any % escapes requiring parameters, they should be specified as subsequent arguments (it's just like printf!). The client host and current date/time are prefixed to every message. """ sys.stderr.write("%s - - [%s] %s\n" % (self.address_string(), self.log_date_time_string(), format%args)) def version_string(self): """Return the server software version string.""" return self.server_version + ' ' + self.sys_version def date_time_string(self): """Return the current date and time formatted for a message header.""" now = time.time() year, month, day, hh, mm, ss, wd, y, z = time.gmtime(now) s = "%s, %02d %3s %4d %02d:%02d:%02d GMT" % ( self.weekdayname[wd], day, self.monthname[month], year, hh, mm, ss) return s def log_date_time_string(self): """Return the current time formatted for logging.""" now = time.time() year, month, day, hh, mm, ss, x, y, z = time.localtime(now) s = "%02d/%3s/%04d %02d:%02d:%02d" % ( day, self.monthname[month], year, hh, mm, ss) return s weekdayname = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'] monthname = [None, 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'] def address_string(self): """Return the client address formatted for logging. This version looks up the full hostname using gethostbyaddr(), and tries to find a name that contains at least one dot. """ (host, port) = self.client_address try: name, names, addresses = socket.gethostbyaddr(host) except socket.error, msg: return host names.insert(0, name) for name in names: if '.' in name: return name return names[0] # Essentially static class variables # The version of the HTTP protocol we support. # Don't override unless you know what you're doing (hint: incoming # requests are required to have exactly this version string). protocol_version = "HTTP/1.0" # The Message-like class used to parse headers MessageClass = mimetools.Message # Table mapping response codes to messages; entries have the # form {code: (shortmessage, longmessage)}. # See http://www.w3.org/hypertext/WWW/Protocols/HTTP/HTRESP.html responses = { 200: ('OK', 'Request fulfilled, document follows'), 201: ('Created', 'Document created, URL follows'), 202: ('Accepted', 'Request accepted, processing continues off-line'), 203: ('Partial information', 'Request fulfilled from cache'), 204: ('No response', 'Request fulfilled, nothing follows'), 301: ('Moved', 'Object moved permanently -- see URI list'), 302: ('Found', 'Object moved temporarily -- see URI list'), 303: ('Method', 'Object moved -- see Method and URL list'), 304: ('Not modified', 'Document has not changed singe given time'), 400: ('Bad request', 'Bad request syntax or unsupported method'), 401: ('Unauthorized', 'No permission -- see authorization schemes'), 402: ('Payment required', 'No payment -- see charging schemes'), 403: ('Forbidden', 'Request forbidden -- authorization will not help'), 404: ('Not found', 'Nothing matches the given URI'), 500: ('Internal error', 'Server got itself in trouble'), 501: ('Not implemented', 'Server does not support this operation'), 502: ('Service temporarily overloaded', 'The server cannot process the request due to a high load'), 503: ('Gateway timeout', 'The gateway server did not receive a timely response'), } def test(HandlerClass = BaseHTTPRequestHandler, ServerClass = HTTPServer): """Test the HTTP request handler class. This runs an HTTP server on port 8000 (or the first command line argument). """ if sys.argv[1:]: port = string.atoi(sys.argv[1]) else: port = 8000 server_address = ('', port) httpd = ServerClass(server_address, HandlerClass) print "Serving HTTP on port", port, "..." httpd.serve_forever() if __name__ == '__main__': test()