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: |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 8 | - AF_INET: IP (Internet Protocol) sockets (default) |
| 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 |
| 53 | using the ForkingServer and ThreadingServer mix-in classes. For |
| 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 |
| 59 | in UDPServer! |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 60 | |
| 61 | To implement a service, you must derive a class from |
| 62 | BaseRequestHandler and redefine its handle() method. You can then run |
| 63 | various versions of the service by combining one of the server classes |
| 64 | with your request handler class. |
| 65 | |
| 66 | The request handler class must be different for datagram or stream |
| 67 | services. This can be hidden by using the mix-in request handler |
| 68 | classes StreamRequestHandler or DatagramRequestHandler. |
| 69 | |
| 70 | Of course, you still have to use your head! |
| 71 | |
| 72 | For instance, it makes no sense to use a forking server if the service |
| 73 | contains state in memory that can be modified by requests (since the |
| 74 | modifications in the child process would never reach the initial state |
| 75 | kept in the parent process and passed to each child). In this case, |
| 76 | you can use a threading server, but you will probably have to use |
| 77 | locks to avoid two requests that come in nearly simultaneous to apply |
| 78 | conflicting changes to the server state. |
| 79 | |
| 80 | On the other hand, if you are building e.g. an HTTP server, where all |
| 81 | data is stored externally (e.g. in the file system), a synchronous |
| 82 | class will essentially render the service "deaf" while one request is |
| 83 | being handled -- which may be for a very long time if a client is slow |
| 84 | to reqd all the data it has requested. Here a threading or forking |
| 85 | server is appropriate. |
| 86 | |
| 87 | In some cases, it may be appropriate to process part of a request |
| 88 | synchronously, but to finish processing in a forked child depending on |
| 89 | the request data. This can be implemented by using a synchronous |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 90 | server and doing an explicit fork in the request handler class |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 91 | handle() method. |
| 92 | |
| 93 | Another approach to handling multiple simultaneous requests in an |
| 94 | environment that supports neither threads nor fork (or where these are |
| 95 | too expensive or inappropriate for the service) is to maintain an |
| 96 | explicit table of partially finished requests and to use select() to |
| 97 | decide which request to work on next (or whether to handle a new |
| 98 | incoming request). This is particularly important for stream services |
| 99 | 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] | 100 | threads or subprocesses cannot be used). |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 101 | |
| 102 | Future work: |
| 103 | - Standard classes for Sun RPC (which uses either UDP or TCP) |
| 104 | - Standard mix-in classes to implement various authentication |
| 105 | and encryption schemes |
| 106 | - Standard framework for select-based multiplexing |
| 107 | |
| 108 | XXX Open problems: |
| 109 | - What to do with out-of-band data? |
| 110 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 111 | BaseServer: |
| 112 | - split generic "request" functionality out into BaseServer class. |
| 113 | Copyright (C) 2000 Luke Kenneth Casson Leighton <lkcl@samba.org> |
| 114 | |
| 115 | example: read entries from a SQL database (requires overriding |
| 116 | get_request() to return a table entry from the database). |
| 117 | entry is processed by a RequestHandlerClass. |
| 118 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 119 | """ |
| 120 | |
Guido van Rossum | 10b0418 | 2001-01-19 16:45:46 +0000 | [diff] [blame] | 121 | # Author of the BaseServer patch: Luke Kenneth Casson Leighton |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 122 | |
Guido van Rossum | 10b0418 | 2001-01-19 16:45:46 +0000 | [diff] [blame] | 123 | __version__ = "0.3" |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 124 | |
| 125 | |
| 126 | import socket |
| 127 | import sys |
| 128 | import os |
| 129 | |
Skip Montanaro | e99d5ea | 2001-01-20 19:54:20 +0000 | [diff] [blame] | 130 | __all__ = ["TCPServer","UDPServer","ForkingUDPServer","ForkingTCPServer", |
| 131 | "ThreadingUDPServer","ThreadingTCPServer","BaseRequestHandler", |
| 132 | "StreamRequestHandler","DatagramRequestHandler"] |
| 133 | if hasattr(socket, "AF_UNIX"): |
| 134 | __all__.extend(["UnixStreamServer","UnixDatagramServer", |
| 135 | "ThreadingUnixStreamServer", |
| 136 | "ThreadingUnixDatagramServer"]) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 137 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 138 | class BaseServer: |
| 139 | |
| 140 | """Base class for server classes. |
| 141 | |
| 142 | Methods for the caller: |
| 143 | |
| 144 | - __init__(server_address, RequestHandlerClass) |
| 145 | - serve_forever() |
| 146 | - handle_request() # if you do not use serve_forever() |
| 147 | - fileno() -> int # for select() |
| 148 | |
| 149 | Methods that may be overridden: |
| 150 | |
| 151 | - server_bind() |
| 152 | - server_activate() |
| 153 | - get_request() -> request, client_address |
| 154 | - verify_request(request, client_address) |
| 155 | - server_close() |
| 156 | - process_request(request, client_address) |
| 157 | - handle_error() |
| 158 | |
| 159 | Methods for derived classes: |
| 160 | |
| 161 | - finish_request(request, client_address) |
| 162 | |
| 163 | Class variables that may be overridden by derived classes or |
| 164 | instances: |
| 165 | |
| 166 | - address_family |
| 167 | - socket_type |
| 168 | - reuse_address |
| 169 | |
| 170 | Instance variables: |
| 171 | |
| 172 | - RequestHandlerClass |
| 173 | - socket |
| 174 | |
| 175 | """ |
| 176 | |
| 177 | def __init__(self, server_address, RequestHandlerClass): |
| 178 | """Constructor. May be extended, do not override.""" |
| 179 | self.server_address = server_address |
| 180 | self.RequestHandlerClass = RequestHandlerClass |
| 181 | |
| 182 | def server_activate(self): |
| 183 | """Called by constructor to activate the server. |
| 184 | |
| 185 | May be overridden. |
| 186 | |
| 187 | """ |
| 188 | pass |
| 189 | |
| 190 | def serve_forever(self): |
| 191 | """Handle one request at a time until doomsday.""" |
| 192 | while 1: |
| 193 | self.handle_request() |
| 194 | |
| 195 | # The distinction between handling, getting, processing and |
| 196 | # finishing a request is fairly arbitrary. Remember: |
| 197 | # |
| 198 | # - handle_request() is the top-level call. It calls |
| 199 | # get_request(), verify_request() and process_request() |
| 200 | # - get_request() is different for stream or datagram sockets |
| 201 | # - process_request() is the place that may fork a new process |
| 202 | # or create a new thread to finish the request |
| 203 | # - finish_request() instantiates the request handler class; |
| 204 | # this constructor will handle the request all by itself |
| 205 | |
| 206 | def handle_request(self): |
| 207 | """Handle one request, possibly blocking.""" |
| 208 | try: |
| 209 | request, client_address = self.get_request() |
| 210 | except socket.error: |
| 211 | return |
| 212 | if self.verify_request(request, client_address): |
| 213 | try: |
| 214 | self.process_request(request, client_address) |
| 215 | except: |
| 216 | self.handle_error(request, client_address) |
| 217 | |
| 218 | def verify_request(self, request, client_address): |
| 219 | """Verify the request. May be overridden. |
| 220 | |
| 221 | Return true if we should proceed with this request. |
| 222 | |
| 223 | """ |
| 224 | return 1 |
| 225 | |
| 226 | def process_request(self, request, client_address): |
| 227 | """Call finish_request. |
| 228 | |
| 229 | Overridden by ForkingMixIn and ThreadingMixIn. |
| 230 | |
| 231 | """ |
| 232 | self.finish_request(request, client_address) |
| 233 | |
| 234 | def server_close(self): |
| 235 | """Called to clean-up the server. |
| 236 | |
| 237 | May be overridden. |
| 238 | |
| 239 | """ |
| 240 | pass |
| 241 | |
| 242 | def finish_request(self, request, client_address): |
| 243 | """Finish one request by instantiating RequestHandlerClass.""" |
| 244 | self.RequestHandlerClass(request, client_address, self) |
| 245 | |
| 246 | def handle_error(self, request, client_address): |
| 247 | """Handle an error gracefully. May be overridden. |
| 248 | |
| 249 | The default is to print a traceback and continue. |
| 250 | |
| 251 | """ |
| 252 | print '-'*40 |
| 253 | print 'Exception happened during processing of request from', |
| 254 | print client_address |
| 255 | import traceback |
| 256 | traceback.print_exc() # XXX But this goes to stderr! |
| 257 | print '-'*40 |
| 258 | |
| 259 | |
| 260 | class TCPServer(BaseServer): |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 261 | |
| 262 | """Base class for various socket-based server classes. |
| 263 | |
| 264 | Defaults to synchronous IP stream (i.e., TCP). |
| 265 | |
| 266 | Methods for the caller: |
| 267 | |
| 268 | - __init__(server_address, RequestHandlerClass) |
| 269 | - serve_forever() |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 270 | - handle_request() # if you don't use serve_forever() |
| 271 | - fileno() -> int # for select() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 272 | |
| 273 | Methods that may be overridden: |
| 274 | |
| 275 | - server_bind() |
| 276 | - server_activate() |
| 277 | - get_request() -> request, client_address |
| 278 | - verify_request(request, client_address) |
| 279 | - process_request(request, client_address) |
| 280 | - handle_error() |
| 281 | |
| 282 | Methods for derived classes: |
| 283 | |
| 284 | - finish_request(request, client_address) |
| 285 | |
| 286 | Class variables that may be overridden by derived classes or |
| 287 | instances: |
| 288 | |
| 289 | - address_family |
| 290 | - socket_type |
| 291 | - request_queue_size (only for stream sockets) |
Guido van Rossum | e3c7a5f | 2000-05-09 14:53:29 +0000 | [diff] [blame] | 292 | - reuse_address |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 293 | |
| 294 | Instance variables: |
| 295 | |
| 296 | - server_address |
| 297 | - RequestHandlerClass |
| 298 | - socket |
| 299 | |
| 300 | """ |
| 301 | |
| 302 | address_family = socket.AF_INET |
| 303 | |
| 304 | socket_type = socket.SOCK_STREAM |
| 305 | |
| 306 | request_queue_size = 5 |
| 307 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 308 | allow_reuse_address = 0 |
Guido van Rossum | e3c7a5f | 2000-05-09 14:53:29 +0000 | [diff] [blame] | 309 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 310 | def __init__(self, server_address, RequestHandlerClass): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 311 | """Constructor. May be extended, do not override.""" |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 312 | BaseServer.__init__(self, server_address, RequestHandlerClass) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 313 | self.socket = socket.socket(self.address_family, |
| 314 | self.socket_type) |
| 315 | self.server_bind() |
| 316 | self.server_activate() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 317 | |
| 318 | def server_bind(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 319 | """Called by constructor to bind the socket. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 320 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 321 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 322 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 323 | """ |
Guido van Rossum | e3c7a5f | 2000-05-09 14:53:29 +0000 | [diff] [blame] | 324 | if self.allow_reuse_address: |
| 325 | self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 326 | self.socket.bind(self.server_address) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 327 | |
| 328 | def server_activate(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 329 | """Called by constructor to activate the server. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 330 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 331 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 332 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 333 | """ |
| 334 | self.socket.listen(self.request_queue_size) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 335 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 336 | def server_close(self): |
| 337 | """Called to clean-up the server. |
| 338 | |
| 339 | May be overridden. |
| 340 | |
| 341 | """ |
| 342 | self.socket.close() |
| 343 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 344 | def fileno(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 345 | """Return socket file number. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 346 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 347 | Interface required by select(). |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 348 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 349 | """ |
| 350 | return self.socket.fileno() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 351 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 352 | def get_request(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 353 | """Get the request and client address from the socket. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 354 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 355 | May be overridden. |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 356 | |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 357 | """ |
| 358 | return self.socket.accept() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 359 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 360 | |
| 361 | class UDPServer(TCPServer): |
| 362 | |
| 363 | """UDP server class.""" |
| 364 | |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 365 | allow_reuse_address = 0 |
| 366 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 367 | socket_type = socket.SOCK_DGRAM |
| 368 | |
| 369 | max_packet_size = 8192 |
| 370 | |
| 371 | def get_request(self): |
Guido van Rossum | 3249082 | 1998-06-16 02:27:33 +0000 | [diff] [blame] | 372 | data, client_addr = self.socket.recvfrom(self.max_packet_size) |
| 373 | return (data, self.socket), client_addr |
| 374 | |
| 375 | def server_activate(self): |
| 376 | # No need to call listen() for UDP. |
| 377 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 378 | |
| 379 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 380 | class ForkingMixIn: |
| 381 | |
| 382 | """Mix-in class to handle each request in a new process.""" |
| 383 | |
| 384 | active_children = None |
Guido van Rossum | 2ab455a | 1999-07-28 21:39:28 +0000 | [diff] [blame] | 385 | max_children = 40 |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 386 | |
| 387 | def collect_children(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 388 | """Internal routine to wait for died children.""" |
| 389 | while self.active_children: |
Guido van Rossum | 2ab455a | 1999-07-28 21:39:28 +0000 | [diff] [blame] | 390 | if len(self.active_children) < self.max_children: |
| 391 | options = os.WNOHANG |
| 392 | else: |
| 393 | # If the maximum number of children are already |
| 394 | # running, block while waiting for a child to exit |
| 395 | options = 0 |
Guido van Rossum | bfadac0 | 1999-06-17 15:41:33 +0000 | [diff] [blame] | 396 | try: |
Guido van Rossum | 2ab455a | 1999-07-28 21:39:28 +0000 | [diff] [blame] | 397 | pid, status = os.waitpid(0, options) |
Guido van Rossum | bfadac0 | 1999-06-17 15:41:33 +0000 | [diff] [blame] | 398 | except os.error: |
| 399 | pid = None |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 400 | if not pid: break |
| 401 | self.active_children.remove(pid) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 402 | |
| 403 | def process_request(self, request, client_address): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 404 | """Fork a new subprocess to process the request.""" |
| 405 | self.collect_children() |
| 406 | pid = os.fork() |
| 407 | if pid: |
| 408 | # Parent process |
| 409 | if self.active_children is None: |
| 410 | self.active_children = [] |
| 411 | self.active_children.append(pid) |
| 412 | return |
| 413 | else: |
| 414 | # Child process. |
| 415 | # This must never return, hence os._exit()! |
| 416 | try: |
Guido van Rossum | 90cb906 | 2001-01-19 00:44:41 +0000 | [diff] [blame] | 417 | self.server_close() |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 418 | self.finish_request(request, client_address) |
| 419 | os._exit(0) |
| 420 | except: |
| 421 | try: |
| 422 | self.handle_error(request, |
| 423 | client_address) |
| 424 | finally: |
| 425 | os._exit(1) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 426 | |
| 427 | |
| 428 | class ThreadingMixIn: |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 429 | """Mix-in class to handle each request in a new thread.""" |
| 430 | |
| 431 | def process_request(self, request, client_address): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 432 | """Start a new thread to process the request.""" |
Jeremy Hylton | 7526027 | 1999-10-12 16:20:13 +0000 | [diff] [blame] | 433 | import threading |
| 434 | t = threading.Thread(target = self.finish_request, |
| 435 | args = (request, client_address)) |
| 436 | t.start() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 437 | |
| 438 | |
| 439 | class ForkingUDPServer(ForkingMixIn, UDPServer): pass |
| 440 | class ForkingTCPServer(ForkingMixIn, TCPServer): pass |
| 441 | |
| 442 | class ThreadingUDPServer(ThreadingMixIn, UDPServer): pass |
| 443 | class ThreadingTCPServer(ThreadingMixIn, TCPServer): pass |
| 444 | |
Guido van Rossum | 67a40e8 | 1998-11-30 15:07:01 +0000 | [diff] [blame] | 445 | if hasattr(socket, 'AF_UNIX'): |
| 446 | |
| 447 | class UnixStreamServer(TCPServer): |
| 448 | address_family = socket.AF_UNIX |
| 449 | |
| 450 | class UnixDatagramServer(UDPServer): |
| 451 | address_family = socket.AF_UNIX |
| 452 | |
| 453 | class ThreadingUnixStreamServer(ThreadingMixIn, UnixStreamServer): pass |
| 454 | |
| 455 | class ThreadingUnixDatagramServer(ThreadingMixIn, UnixDatagramServer): pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 456 | |
| 457 | class BaseRequestHandler: |
| 458 | |
| 459 | """Base class for request handler classes. |
| 460 | |
| 461 | This class is instantiated for each request to be handled. The |
| 462 | constructor sets the instance variables request, client_address |
| 463 | and server, and then calls the handle() method. To implement a |
| 464 | specific service, all you need to do is to derive a class which |
| 465 | defines a handle() method. |
| 466 | |
| 467 | The handle() method can find the request as self.request, the |
Guido van Rossum | fdb3d1a | 1998-11-16 19:06:30 +0000 | [diff] [blame] | 468 | 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] | 469 | needs access to per-server information) as self.server. Since a |
| 470 | separate instance is created for each request, the handle() method |
| 471 | can define arbitrary other instance variariables. |
| 472 | |
| 473 | """ |
| 474 | |
| 475 | def __init__(self, request, client_address, server): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 476 | self.request = request |
| 477 | self.client_address = client_address |
| 478 | self.server = server |
| 479 | try: |
| 480 | self.setup() |
| 481 | self.handle() |
| 482 | self.finish() |
| 483 | finally: |
| 484 | sys.exc_traceback = None # Help garbage collection |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 485 | |
| 486 | def setup(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 487 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 488 | |
| 489 | def __del__(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 490 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 491 | |
| 492 | def handle(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 493 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 494 | |
| 495 | def finish(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 496 | pass |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 497 | |
| 498 | |
| 499 | # The following two classes make it possible to use the same service |
| 500 | # class for stream or datagram servers. |
| 501 | # Each class sets up these instance variables: |
| 502 | # - rfile: a file object from which receives the request is read |
| 503 | # - wfile: a file object to which the reply is written |
| 504 | # When the handle() method returns, wfile is flushed properly |
| 505 | |
| 506 | |
| 507 | class StreamRequestHandler(BaseRequestHandler): |
| 508 | |
| 509 | """Define self.rfile and self.wfile for stream sockets.""" |
| 510 | |
Guido van Rossum | 01fed4d | 2000-09-01 03:25:14 +0000 | [diff] [blame] | 511 | # Default buffer sizes for rfile, wfile. |
| 512 | # We default rfile to buffered because otherwise it could be |
| 513 | # really slow for large data (a getc() call per byte); we make |
| 514 | # wfile unbuffered because (a) often after a write() we want to |
| 515 | # read and we need to flush the line; (b) big writes to unbuffered |
| 516 | # files are typically optimized by stdio even when big reads |
| 517 | # aren't. |
| 518 | rbufsize = -1 |
| 519 | wbufsize = 0 |
| 520 | |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 521 | def setup(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 522 | self.connection = self.request |
Guido van Rossum | 01fed4d | 2000-09-01 03:25:14 +0000 | [diff] [blame] | 523 | self.rfile = self.connection.makefile('rb', self.rbufsize) |
| 524 | self.wfile = self.connection.makefile('wb', self.wbufsize) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 525 | |
| 526 | def finish(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 527 | self.wfile.flush() |
Guido van Rossum | 1d5102c | 1998-04-03 16:49:52 +0000 | [diff] [blame] | 528 | self.wfile.close() |
| 529 | self.rfile.close() |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 530 | |
| 531 | |
| 532 | class DatagramRequestHandler(BaseRequestHandler): |
| 533 | |
| 534 | """Define self.rfile and self.wfile for datagram sockets.""" |
| 535 | |
| 536 | def setup(self): |
Guido van Rossum | 45e2fbc | 1998-03-26 21:13:24 +0000 | [diff] [blame] | 537 | import StringIO |
| 538 | self.packet, self.socket = self.request |
| 539 | self.rfile = StringIO.StringIO(self.packet) |
| 540 | self.wfile = StringIO.StringIO(self.packet) |
Guido van Rossum | e7e578f | 1995-08-04 04:00:20 +0000 | [diff] [blame] | 541 | |
| 542 | def finish(self): |
Guido van Rossum | 3249082 | 1998-06-16 02:27:33 +0000 | [diff] [blame] | 543 | self.socket.sendto(self.wfile.getvalue(), self.client_address) |