Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 1 | """Generic socket server classes. |
| 2 | |
| 3 | This module tries to capture the various aspects of defining a server: |
| 4 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 5 | For socket-based servers: |
| 6 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 7 | - address family: |
Martin v. Löwis | a43c2f8 | 2001-07-24 20:34:08 +0000 | [diff] [blame] | 8 | - AF_INET{,6}: IP (Internet Protocol) sockets (default) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 9 | - AF_UNIX: Unix domain sockets |
| 10 | - others, e.g. AF_DECNET are conceivable (see <socket.h> |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 11 | - socket type: |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 12 | - SOCK_STREAM (reliable stream, e.g. TCP) |
| 13 | - SOCK_DGRAM (datagrams, e.g. UDP) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 14 | |
| 15 | For request-based servers (including socket-based): |
| 16 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 17 | - client address verification before further looking at the request |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 18 | (This is actually a hook for any processing that needs to look |
| 19 | at the request before anything else, e.g. logging) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 20 | - how to handle multiple requests: |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 21 | - synchronous (one request is handled at a time) |
| 22 | - forking (each request is handled by a new process) |
| 23 | - threading (each request is handled by a new thread) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 24 | |
| 25 | The classes in this module favor the server type that is simplest to |
| 26 | write: a synchronous TCP/IP server. This is bad class design, but |
| 27 | save some typing. (There's also the issue that a deep class hierarchy |
| 28 | slows down method lookups.) |
| 29 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 30 | There are five classes in an inheritance diagram, four of which represent |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 31 | synchronous servers of four types: |
| 32 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 33 | +------------+ |
| 34 | | BaseServer | |
| 35 | +------------+ |
| 36 | | |
| 37 | v |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 38 | +-----------+ +------------------+ |
| 39 | | TCPServer |------->| UnixStreamServer | |
| 40 | +-----------+ +------------------+ |
| 41 | | |
| 42 | v |
| 43 | +-----------+ +--------------------+ |
| 44 | | UDPServer |------->| UnixDatagramServer | |
| 45 | +-----------+ +--------------------+ |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 46 | |
Guido van Rossum | db2b70c | 1997-07-16 16:21:38 +0000 | [diff] [blame] | 47 | Note that UnixDatagramServer derives from UDPServer, not from |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 48 | UnixStreamServer -- the only difference between an IP and a Unix |
| 49 | stream server is the address family, which is simply repeated in both |
Guido van Rossum | db2b70c | 1997-07-16 16:21:38 +0000 | [diff] [blame] | 50 | unix server classes. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 51 | |
| 52 | Forking and threading versions of each type of server can be created |
Guido van Rossum | ebbffd4 | 2005-04-30 00:20:35 +0000 | [diff] [blame] | 53 | using the ForkingMixIn and ThreadingMixIn mix-in classes. For |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 54 | instance, a threading UDP server class is created as follows: |
| 55 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 56 | class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 57 | |
Guido van Rossum | db2b70c | 1997-07-16 16:21:38 +0000 | [diff] [blame] | 58 | The Mix-in class must come first, since it overrides a method defined |
Martin v. Löwis | f86e8ef | 2002-11-22 08:08:44 +0000 | [diff] [blame] | 59 | in UDPServer! Setting the various member variables also changes |
| 60 | the behavior of the underlying server mechanism. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 61 | |
| 62 | To implement a service, you must derive a class from |
| 63 | BaseRequestHandler and redefine its handle() method. You can then run |
| 64 | various versions of the service by combining one of the server classes |
| 65 | with your request handler class. |
| 66 | |
| 67 | The request handler class must be different for datagram or stream |
Georg Brandl | ca5feab | 2005-07-18 07:38:44 +0000 | [diff] [blame] | 68 | services. This can be hidden by using the request handler |
| 69 | subclasses StreamRequestHandler or DatagramRequestHandler. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 70 | |
| 71 | Of course, you still have to use your head! |
| 72 | |
| 73 | For instance, it makes no sense to use a forking server if the service |
| 74 | contains state in memory that can be modified by requests (since the |
| 75 | modifications in the child process would never reach the initial state |
| 76 | kept in the parent process and passed to each child). In this case, |
| 77 | you can use a threading server, but you will probably have to use |
| 78 | locks to avoid two requests that come in nearly simultaneous to apply |
| 79 | conflicting changes to the server state. |
| 80 | |
| 81 | On the other hand, if you are building e.g. an HTTP server, where all |
| 82 | data is stored externally (e.g. in the file system), a synchronous |
| 83 | class will essentially render the service "deaf" while one request is |
| 84 | being handled -- which may be for a very long time if a client is slow |
| 85 | to reqd all the data it has requested. Here a threading or forking |
| 86 | server is appropriate. |
| 87 | |
| 88 | In some cases, it may be appropriate to process part of a request |
| 89 | synchronously, but to finish processing in a forked child depending on |
| 90 | the request data. This can be implemented by using a synchronous |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 91 | server and doing an explicit fork in the request handler class |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 92 | handle() method. |
| 93 | |
| 94 | Another approach to handling multiple simultaneous requests in an |
| 95 | environment that supports neither threads nor fork (or where these are |
| 96 | too expensive or inappropriate for the service) is to maintain an |
| 97 | explicit table of partially finished requests and to use select() to |
| 98 | decide which request to work on next (or whether to handle a new |
| 99 | incoming request). This is particularly important for stream services |
| 100 | where each client can potentially be connected for a long time (if |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 101 | threads or subprocesses cannot be used). |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 102 | |
| 103 | Future work: |
| 104 | - Standard classes for Sun RPC (which uses either UDP or TCP) |
| 105 | - Standard mix-in classes to implement various authentication |
| 106 | and encryption schemes |
| 107 | - Standard framework for select-based multiplexing |
| 108 | |
| 109 | XXX Open problems: |
| 110 | - What to do with out-of-band data? |
| 111 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 112 | BaseServer: |
| 113 | - split generic "request" functionality out into BaseServer class. |
| 114 | Copyright (C) 2000 Luke Kenneth Casson Leighton <lkcl@samba.org> |
| 115 | |
| 116 | example: read entries from a SQL database (requires overriding |
| 117 | get_request() to return a table entry from the database). |
| 118 | entry is processed by a RequestHandlerClass. |
| 119 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 120 | """ |
| 121 | |
Guido van Rossum | 10b0418 | 2001-01-19 16:45:46 +0000 | [diff] [blame] | 122 | # Author of the BaseServer patch: Luke Kenneth Casson Leighton |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 123 | |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 124 | # XXX Warning! |
| 125 | # There is a test suite for this module, but it cannot be run by the |
| 126 | # standard regression test. |
| 127 | # To run it manually, run Lib/test/test_socketserver.py. |
| 128 | |
| 129 | __version__ = "0.4" |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 130 | |
| 131 | |
| 132 | import socket |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 133 | import select |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 134 | import sys |
| 135 | import os |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 136 | try: |
| 137 | import threading |
| 138 | except ImportError: |
| 139 | import dummy_threading as threading |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 140 | |
Skip Montanaro | e99d5ea | 2001-01-20 19:54:20 +0000 | [diff] [blame] | 141 | __all__ = ["TCPServer","UDPServer","ForkingUDPServer","ForkingTCPServer", |
| 142 | "ThreadingUDPServer","ThreadingTCPServer","BaseRequestHandler", |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 143 | "StreamRequestHandler","DatagramRequestHandler", |
| 144 | "ThreadingMixIn", "ForkingMixIn"] |
Skip Montanaro | e99d5ea | 2001-01-20 19:54:20 +0000 | [diff] [blame] | 145 | if hasattr(socket, "AF_UNIX"): |
| 146 | __all__.extend(["UnixStreamServer","UnixDatagramServer", |
| 147 | "ThreadingUnixStreamServer", |
| 148 | "ThreadingUnixDatagramServer"]) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 149 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 150 | class BaseServer: |
| 151 | |
| 152 | """Base class for server classes. |
| 153 | |
| 154 | Methods for the caller: |
| 155 | |
| 156 | - __init__(server_address, RequestHandlerClass) |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 157 | - serve_forever(poll_interval=0.5) |
| 158 | - shutdown() |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 159 | - handle_request() # if you do not use serve_forever() |
| 160 | - fileno() -> int # for select() |
| 161 | |
| 162 | Methods that may be overridden: |
| 163 | |
| 164 | - server_bind() |
| 165 | - server_activate() |
| 166 | - get_request() -> request, client_address |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 167 | - handle_timeout() |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 168 | - verify_request(request, client_address) |
| 169 | - server_close() |
| 170 | - process_request(request, client_address) |
Ka-Ping Yee | 285a7e5 | 2001-04-11 04:02:05 +0000 | [diff] [blame] | 171 | - close_request(request) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 172 | - handle_error() |
| 173 | |
| 174 | Methods for derived classes: |
| 175 | |
| 176 | - finish_request(request, client_address) |
| 177 | |
| 178 | Class variables that may be overridden by derived classes or |
| 179 | instances: |
| 180 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 181 | - timeout |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 182 | - address_family |
| 183 | - socket_type |
Barry Warsaw | b97f0b7 | 2003-10-09 23:48:52 +0000 | [diff] [blame] | 184 | - allow_reuse_address |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 185 | |
| 186 | Instance variables: |
| 187 | |
| 188 | - RequestHandlerClass |
| 189 | - socket |
| 190 | |
| 191 | """ |
| 192 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 193 | timeout = None |
| 194 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 195 | def __init__(self, server_address, RequestHandlerClass): |
| 196 | """Constructor. May be extended, do not override.""" |
| 197 | self.server_address = server_address |
| 198 | self.RequestHandlerClass = RequestHandlerClass |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 199 | self.__is_shut_down = threading.Event() |
| 200 | self.__serving = False |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 201 | |
| 202 | def server_activate(self): |
| 203 | """Called by constructor to activate the server. |
| 204 | |
| 205 | May be overridden. |
| 206 | |
| 207 | """ |
| 208 | pass |
| 209 | |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 210 | def serve_forever(self, poll_interval=0.5): |
| 211 | """Handle one request at a time until shutdown. |
| 212 | |
| 213 | Polls for shutdown every poll_interval seconds. Ignores |
| 214 | self.timeout. If you need to do periodic tasks, do them in |
| 215 | another thread. |
| 216 | """ |
| 217 | self.__serving = True |
| 218 | self.__is_shut_down.clear() |
| 219 | while self.__serving: |
| 220 | # XXX: Consider using another file descriptor or |
| 221 | # connecting to the socket to wake this up instead of |
| 222 | # polling. Polling reduces our responsiveness to a |
| 223 | # shutdown request and wastes cpu at all other times. |
| 224 | r, w, e = select.select([self], [], [], poll_interval) |
| 225 | if r: |
| 226 | self._handle_request_noblock() |
| 227 | self.__is_shut_down.set() |
| 228 | |
| 229 | def shutdown(self): |
| 230 | """Stops the serve_forever loop. |
| 231 | |
| 232 | Blocks until the loop has finished. This must be called while |
| 233 | serve_forever() is running in another thread, or it will |
| 234 | deadlock. |
| 235 | """ |
| 236 | self.__serving = False |
| 237 | self.__is_shut_down.wait() |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 238 | |
| 239 | # The distinction between handling, getting, processing and |
| 240 | # finishing a request is fairly arbitrary. Remember: |
| 241 | # |
| 242 | # - handle_request() is the top-level call. It calls |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 243 | # select, get_request(), verify_request() and process_request() |
| 244 | # - get_request() is different for stream or datagram sockets |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 245 | # - process_request() is the place that may fork a new process |
| 246 | # or create a new thread to finish the request |
| 247 | # - finish_request() instantiates the request handler class; |
| 248 | # this constructor will handle the request all by itself |
| 249 | |
| 250 | def handle_request(self): |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 251 | """Handle one request, possibly blocking. |
| 252 | |
| 253 | Respects self.timeout. |
| 254 | """ |
| 255 | # Support people who used socket.settimeout() to escape |
| 256 | # handle_request before self.timeout was available. |
| 257 | timeout = self.socket.gettimeout() |
| 258 | if timeout is None: |
| 259 | timeout = self.timeout |
| 260 | elif self.timeout is not None: |
| 261 | timeout = min(timeout, self.timeout) |
| 262 | fd_sets = select.select([self], [], [], timeout) |
| 263 | if not fd_sets[0]: |
| 264 | self.handle_timeout() |
| 265 | return |
| 266 | self._handle_request_noblock() |
| 267 | |
| 268 | def _handle_request_noblock(self): |
| 269 | """Handle one request, without blocking. |
| 270 | |
| 271 | I assume that select.select has returned that the socket is |
| 272 | readable before this function was called, so there should be |
| 273 | no risk of blocking in get_request(). |
| 274 | """ |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 275 | try: |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 276 | request, client_address = self.get_request() |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 277 | except socket.error: |
| 278 | return |
| 279 | if self.verify_request(request, client_address): |
| 280 | try: |
| 281 | self.process_request(request, client_address) |
| 282 | except: |
| 283 | self.handle_error(request, client_address) |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 284 | self.close_request(request) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 285 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 286 | def handle_timeout(self): |
| 287 | """Called if no new request arrives within self.timeout. |
| 288 | |
| 289 | Overridden by ForkingMixIn. |
| 290 | """ |
| 291 | pass |
| 292 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 293 | def verify_request(self, request, client_address): |
| 294 | """Verify the request. May be overridden. |
| 295 | |
Tim Peters | bc0e910 | 2002-04-04 22:55:58 +0000 | [diff] [blame] | 296 | Return True if we should proceed with this request. |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 297 | |
| 298 | """ |
Tim Peters | bc0e910 | 2002-04-04 22:55:58 +0000 | [diff] [blame] | 299 | return True |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 300 | |
| 301 | def process_request(self, request, client_address): |
| 302 | """Call finish_request. |
| 303 | |
| 304 | Overridden by ForkingMixIn and ThreadingMixIn. |
| 305 | |
| 306 | """ |
| 307 | self.finish_request(request, client_address) |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 308 | self.close_request(request) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 309 | |
| 310 | def server_close(self): |
| 311 | """Called to clean-up the server. |
| 312 | |
| 313 | May be overridden. |
| 314 | |
| 315 | """ |
| 316 | pass |
| 317 | |
| 318 | def finish_request(self, request, client_address): |
| 319 | """Finish one request by instantiating RequestHandlerClass.""" |
| 320 | self.RequestHandlerClass(request, client_address, self) |
| 321 | |
Ka-Ping Yee | 285a7e5 | 2001-04-11 04:02:05 +0000 | [diff] [blame] | 322 | def close_request(self, request): |
| 323 | """Called to clean up an individual request.""" |
| 324 | pass |
| 325 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 326 | def handle_error(self, request, client_address): |
| 327 | """Handle an error gracefully. May be overridden. |
| 328 | |
| 329 | The default is to print a traceback and continue. |
| 330 | |
| 331 | """ |
Guido van Rossum | be19ed7 | 2007-02-09 05:37:30 +0000 | [diff] [blame] | 332 | print('-'*40) |
| 333 | print('Exception happened during processing of request from', end=' ') |
| 334 | print(client_address) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 335 | import traceback |
| 336 | traceback.print_exc() # XXX But this goes to stderr! |
Guido van Rossum | be19ed7 | 2007-02-09 05:37:30 +0000 | [diff] [blame] | 337 | print('-'*40) |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 338 | |
| 339 | |
| 340 | class TCPServer(BaseServer): |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 341 | |
| 342 | """Base class for various socket-based server classes. |
| 343 | |
| 344 | Defaults to synchronous IP stream (i.e., TCP). |
| 345 | |
| 346 | Methods for the caller: |
| 347 | |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 348 | - __init__(server_address, RequestHandlerClass, bind_and_activate=True) |
Christian Heimes | dd15f6c | 2008-03-16 00:07:10 +0000 | [diff] [blame] | 349 | - serve_forever(poll_interval=0.5) |
| 350 | - shutdown() |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 351 | - handle_request() # if you don't use serve_forever() |
| 352 | - fileno() -> int # for select() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 353 | |
| 354 | Methods that may be overridden: |
| 355 | |
| 356 | - server_bind() |
| 357 | - server_activate() |
| 358 | - get_request() -> request, client_address |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 359 | - handle_timeout() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 360 | - verify_request(request, client_address) |
| 361 | - process_request(request, client_address) |
Ka-Ping Yee | 285a7e5 | 2001-04-11 04:02:05 +0000 | [diff] [blame] | 362 | - close_request(request) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 363 | - handle_error() |
| 364 | |
| 365 | Methods for derived classes: |
| 366 | |
| 367 | - finish_request(request, client_address) |
| 368 | |
| 369 | Class variables that may be overridden by derived classes or |
| 370 | instances: |
| 371 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 372 | - timeout |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 373 | - address_family |
| 374 | - socket_type |
| 375 | - request_queue_size (only for stream sockets) |
Barry Warsaw | 3aaad50 | 2003-10-09 22:44:05 +0000 | [diff] [blame] | 376 | - allow_reuse_address |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 377 | |
| 378 | Instance variables: |
| 379 | |
| 380 | - server_address |
| 381 | - RequestHandlerClass |
| 382 | - socket |
| 383 | |
| 384 | """ |
| 385 | |
| 386 | address_family = socket.AF_INET |
| 387 | |
| 388 | socket_type = socket.SOCK_STREAM |
| 389 | |
| 390 | request_queue_size = 5 |
| 391 | |
Raymond Hettinger | c8f8034 | 2002-08-25 16:36:49 +0000 | [diff] [blame] | 392 | allow_reuse_address = False |
Guido van Rossum | e3c7a5f | 2000-05-09 14:53:29 +0000 | [diff] [blame] | 393 | |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 394 | def __init__(self, server_address, RequestHandlerClass, bind_and_activate=True): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 395 | """Constructor. May be extended, do not override.""" |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 396 | BaseServer.__init__(self, server_address, RequestHandlerClass) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 397 | self.socket = socket.socket(self.address_family, |
| 398 | self.socket_type) |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 399 | if bind_and_activate: |
| 400 | self.server_bind() |
| 401 | self.server_activate() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 402 | |
| 403 | def server_bind(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 404 | """Called by constructor to bind the socket. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 405 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 406 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 407 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 408 | """ |
Guido van Rossum | e3c7a5f | 2000-05-09 14:53:29 +0000 | [diff] [blame] | 409 | if self.allow_reuse_address: |
| 410 | self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 411 | self.socket.bind(self.server_address) |
Guido van Rossum | d8faa36 | 2007-04-27 19:54:29 +0000 | [diff] [blame] | 412 | self.server_address = self.socket.getsockname() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 413 | |
| 414 | def server_activate(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 415 | """Called by constructor to activate the server. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 416 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 417 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 418 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 419 | """ |
| 420 | self.socket.listen(self.request_queue_size) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 421 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 422 | def server_close(self): |
| 423 | """Called to clean-up the server. |
| 424 | |
| 425 | May be overridden. |
| 426 | |
| 427 | """ |
| 428 | self.socket.close() |
| 429 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 430 | def fileno(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 431 | """Return socket file number. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 432 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 433 | Interface required by select(). |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 434 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 435 | """ |
| 436 | return self.socket.fileno() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 437 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 438 | def get_request(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 439 | """Get the request and client address from the socket. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 440 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 441 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 442 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 443 | """ |
| 444 | return self.socket.accept() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 445 | |
Ka-Ping Yee | 285a7e5 | 2001-04-11 04:02:05 +0000 | [diff] [blame] | 446 | def close_request(self, request): |
| 447 | """Called to clean up an individual request.""" |
| 448 | request.close() |
| 449 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 450 | |
| 451 | class UDPServer(TCPServer): |
| 452 | |
| 453 | """UDP server class.""" |
| 454 | |
Raymond Hettinger | c8f8034 | 2002-08-25 16:36:49 +0000 | [diff] [blame] | 455 | allow_reuse_address = False |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 456 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 457 | socket_type = socket.SOCK_DGRAM |
| 458 | |
| 459 | max_packet_size = 8192 |
| 460 | |
| 461 | def get_request(self): |
Guido van Rossum | 3249082 | 1998-06-16 02:27:33 +0000 | [diff] [blame] | 462 | data, client_addr = self.socket.recvfrom(self.max_packet_size) |
| 463 | return (data, self.socket), client_addr |
| 464 | |
| 465 | def server_activate(self): |
| 466 | # No need to call listen() for UDP. |
| 467 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 468 | |
Ka-Ping Yee | 285a7e5 | 2001-04-11 04:02:05 +0000 | [diff] [blame] | 469 | def close_request(self, request): |
| 470 | # No need to close anything. |
| 471 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 472 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 473 | class ForkingMixIn: |
| 474 | |
| 475 | """Mix-in class to handle each request in a new process.""" |
| 476 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 477 | timeout = 300 |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 478 | active_children = None |
Guido van Rossum | 2ab455a | 1999-07-28 21:39:28 +0000 | [diff] [blame] | 479 | max_children = 40 |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 480 | |
| 481 | def collect_children(self): |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 482 | """Internal routine to wait for children that have exited.""" |
Christian Heimes | 70e7ea2 | 2008-02-28 20:02:27 +0000 | [diff] [blame] | 483 | if self.active_children is None: return |
| 484 | while len(self.active_children) >= self.max_children: |
| 485 | # XXX: This will wait for any child process, not just ones |
| 486 | # spawned by this library. This could confuse other |
| 487 | # libraries that expect to be able to wait for their own |
| 488 | # children. |
Guido van Rossum | bfadac0 | 1999-06-17 15:41:33 +0000 | [diff] [blame] | 489 | try: |
Benjamin Peterson | ad3d5c2 | 2009-02-26 03:38:59 +0000 | [diff] [blame] | 490 | pid, status = os.waitpid(0, 0) |
Guido van Rossum | bfadac0 | 1999-06-17 15:41:33 +0000 | [diff] [blame] | 491 | except os.error: |
| 492 | pid = None |
Christian Heimes | 70e7ea2 | 2008-02-28 20:02:27 +0000 | [diff] [blame] | 493 | if pid not in self.active_children: continue |
| 494 | self.active_children.remove(pid) |
| 495 | |
| 496 | # XXX: This loop runs more system calls than it ought |
| 497 | # to. There should be a way to put the active_children into a |
| 498 | # process group and then use os.waitpid(-pgid) to wait for any |
| 499 | # of that set, but I couldn't find a way to allocate pgids |
| 500 | # that couldn't collide. |
| 501 | for child in self.active_children: |
| 502 | try: |
| 503 | pid, status = os.waitpid(child, os.WNOHANG) |
| 504 | except os.error: |
| 505 | pid = None |
| 506 | if not pid: continue |
Christian Heimes | a156e09 | 2008-02-16 07:38:31 +0000 | [diff] [blame] | 507 | try: |
| 508 | self.active_children.remove(pid) |
| 509 | except ValueError as e: |
| 510 | raise ValueError('%s. x=%d and list=%r' % (e.message, pid, |
| 511 | self.active_children)) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 512 | |
Georg Brandl | fceab5a | 2008-01-19 20:08:23 +0000 | [diff] [blame] | 513 | def handle_timeout(self): |
| 514 | """Wait for zombies after self.timeout seconds of inactivity. |
| 515 | |
| 516 | May be extended, do not override. |
| 517 | """ |
| 518 | self.collect_children() |
| 519 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 520 | def process_request(self, request, client_address): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 521 | """Fork a new subprocess to process the request.""" |
| 522 | self.collect_children() |
| 523 | pid = os.fork() |
| 524 | if pid: |
| 525 | # Parent process |
| 526 | if self.active_children is None: |
| 527 | self.active_children = [] |
| 528 | self.active_children.append(pid) |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 529 | self.close_request(request) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 530 | return |
| 531 | else: |
| 532 | # Child process. |
| 533 | # This must never return, hence os._exit()! |
| 534 | try: |
| 535 | self.finish_request(request, client_address) |
| 536 | os._exit(0) |
| 537 | except: |
| 538 | try: |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 539 | self.handle_error(request, client_address) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 540 | finally: |
| 541 | os._exit(1) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 542 | |
| 543 | |
| 544 | class ThreadingMixIn: |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 545 | """Mix-in class to handle each request in a new thread.""" |
| 546 | |
Martin v. Löwis | f86e8ef | 2002-11-22 08:08:44 +0000 | [diff] [blame] | 547 | # Decides how threads will act upon termination of the |
| 548 | # main process |
Fred Drake | 132e0e8 | 2002-11-22 14:22:49 +0000 | [diff] [blame] | 549 | daemon_threads = False |
Martin v. Löwis | f86e8ef | 2002-11-22 08:08:44 +0000 | [diff] [blame] | 550 | |
Guido van Rossum | a5343cc | 2001-10-18 18:02:07 +0000 | [diff] [blame] | 551 | def process_request_thread(self, request, client_address): |
Guido van Rossum | 83c3281 | 2001-10-23 21:42:45 +0000 | [diff] [blame] | 552 | """Same as in BaseServer but as a thread. |
| 553 | |
| 554 | In addition, exception handling is done here. |
| 555 | |
| 556 | """ |
| 557 | try: |
| 558 | self.finish_request(request, client_address) |
| 559 | self.close_request(request) |
| 560 | except: |
| 561 | self.handle_error(request, client_address) |
| 562 | self.close_request(request) |
Guido van Rossum | a5343cc | 2001-10-18 18:02:07 +0000 | [diff] [blame] | 563 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 564 | def process_request(self, request, client_address): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 565 | """Start a new thread to process the request.""" |
Guido van Rossum | a5343cc | 2001-10-18 18:02:07 +0000 | [diff] [blame] | 566 | t = threading.Thread(target = self.process_request_thread, |
Jeremy Hylton | 7526027 | 1999-10-12 16:20:13 +0000 | [diff] [blame] | 567 | args = (request, client_address)) |
Martin v. Löwis | f86e8ef | 2002-11-22 08:08:44 +0000 | [diff] [blame] | 568 | if self.daemon_threads: |
Benjamin Peterson | 8b6dc5c | 2008-09-20 12:52:07 +0000 | [diff] [blame] | 569 | t.daemon = True |
Jeremy Hylton | 7526027 | 1999-10-12 16:20:13 +0000 | [diff] [blame] | 570 | t.start() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 571 | |
| 572 | |
| 573 | class ForkingUDPServer(ForkingMixIn, UDPServer): pass |
| 574 | class ForkingTCPServer(ForkingMixIn, TCPServer): pass |
| 575 | |
| 576 | class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass |
| 577 | class ThreadingTCPServer(ThreadingMixIn, TCPServer): pass |
| 578 | |
Guido van Rossum | 67a40e8 | 1998-11-30 15:07:01 +0000 | [diff] [blame] | 579 | if hasattr(socket, 'AF_UNIX'): |
| 580 | |
| 581 | class UnixStreamServer(TCPServer): |
| 582 | address_family = socket.AF_UNIX |
| 583 | |
| 584 | class UnixDatagramServer(UDPServer): |
| 585 | address_family = socket.AF_UNIX |
| 586 | |
| 587 | class ThreadingUnixStreamServer(ThreadingMixIn, UnixStreamServer): pass |
| 588 | |
| 589 | class ThreadingUnixDatagramServer(ThreadingMixIn, UnixDatagramServer): pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 590 | |
| 591 | class BaseRequestHandler: |
| 592 | |
| 593 | """Base class for request handler classes. |
| 594 | |
| 595 | This class is instantiated for each request to be handled. The |
| 596 | constructor sets the instance variables request, client_address |
| 597 | and server, and then calls the handle() method. To implement a |
| 598 | specific service, all you need to do is to derive a class which |
| 599 | defines a handle() method. |
| 600 | |
| 601 | The handle() method can find the request as self.request, the |
Guido van Rossum | fdb3d1a | 1998-11-16 19:06:30 +0000 | [diff] [blame] | 602 | client address as self.client_address, and the server (in case it |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 603 | needs access to per-server information) as self.server. Since a |
| 604 | separate instance is created for each request, the handle() method |
| 605 | can define arbitrary other instance variariables. |
| 606 | |
| 607 | """ |
| 608 | |
| 609 | def __init__(self, request, client_address, server): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 610 | self.request = request |
| 611 | self.client_address = client_address |
| 612 | self.server = server |
Guido van Rossum | e7ba495 | 2007-06-06 23:52:48 +0000 | [diff] [blame] | 613 | self.setup() |
| 614 | self.handle() |
| 615 | self.finish() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 616 | |
| 617 | def setup(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 618 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 619 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 620 | def handle(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 621 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 622 | |
| 623 | def finish(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 624 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 625 | |
| 626 | |
| 627 | # The following two classes make it possible to use the same service |
| 628 | # class for stream or datagram servers. |
| 629 | # Each class sets up these instance variables: |
| 630 | # - rfile: a file object from which receives the request is read |
| 631 | # - wfile: a file object to which the reply is written |
| 632 | # When the handle() method returns, wfile is flushed properly |
| 633 | |
| 634 | |
| 635 | class StreamRequestHandler(BaseRequestHandler): |
| 636 | |
| 637 | """Define self.rfile and self.wfile for stream sockets.""" |
| 638 | |
Guido van Rossum | 01fed4d | 2000-09-01 03:25:14 +0000 | [diff] [blame] | 639 | # Default buffer sizes for rfile, wfile. |
| 640 | # We default rfile to buffered because otherwise it could be |
| 641 | # really slow for large data (a getc() call per byte); we make |
| 642 | # wfile unbuffered because (a) often after a write() we want to |
| 643 | # read and we need to flush the line; (b) big writes to unbuffered |
| 644 | # files are typically optimized by stdio even when big reads |
| 645 | # aren't. |
| 646 | rbufsize = -1 |
| 647 | wbufsize = 0 |
| 648 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 649 | def setup(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 650 | self.connection = self.request |
Guido van Rossum | 01fed4d | 2000-09-01 03:25:14 +0000 | [diff] [blame] | 651 | self.rfile = self.connection.makefile('rb', self.rbufsize) |
| 652 | self.wfile = self.connection.makefile('wb', self.wbufsize) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 653 | |
| 654 | def finish(self): |
Anthony Baxter | 4cedc1e | 2003-01-02 03:07:48 +0000 | [diff] [blame] | 655 | if not self.wfile.closed: |
| 656 | self.wfile.flush() |
Guido van Rossum | 1d5102c | 1998-04-03 16:49:52 +0000 | [diff] [blame] | 657 | self.wfile.close() |
| 658 | self.rfile.close() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 659 | |
| 660 | |
| 661 | class DatagramRequestHandler(BaseRequestHandler): |
| 662 | |
Guido van Rossum | 7de4d64 | 2001-07-10 11:50:09 +0000 | [diff] [blame] | 663 | # XXX Regrettably, I cannot get this working on Linux; |
| 664 | # s.recvfrom() doesn't return a meaningful client address. |
| 665 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 666 | """Define self.rfile and self.wfile for datagram sockets.""" |
| 667 | |
| 668 | def setup(self): |
Guido van Rossum | 15863ea | 2007-08-03 19:03:39 +0000 | [diff] [blame] | 669 | from io import BytesIO |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 670 | self.packet, self.socket = self.request |
Guido van Rossum | 15863ea | 2007-08-03 19:03:39 +0000 | [diff] [blame] | 671 | self.rfile = BytesIO(self.packet) |
| 672 | self.wfile = BytesIO() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 673 | |
| 674 | def finish(self): |
Guido van Rossum | 3249082 | 1998-06-16 02:27:33 +0000 | [diff] [blame] | 675 | self.socket.sendto(self.wfile.getvalue(), self.client_address) |