acceptor.lisp

   1 ;;; -*- Mode: LISP; Syntax: COMMON-LISP; Package: CL-USER; Base: 10 -*-
   2
   3 ;;; Copyright (c) 2004-2010, Dr. Edmund Weitz.  All rights reserved.
   4
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  28
  29 (in-package :hunchentoot)
  30
  31 (eval-when (:load-toplevel :compile-toplevel :execute)
  32   (defun default-document-directory (&optional sub-directory)
  33     (let ((source-directory #.(or *compile-file-truename* *load-truename*)))
  34       (merge-pathnames (make-pathname :directory (append (pathname-directory source-directory)
  35                                                          (list "www")
  36                                                          (when sub-directory
  37                                                            (list sub-directory)))
  38                                       :name nil
  39                                       :type nil
  40                                       :defaults source-directory)))))
  41
  42 (defclass acceptor ()
  43   ((port :initarg :port
  44          :reader acceptor-port
  45          :documentation "The port the acceptor is listening on.  The
  46 default is 80.  Note that depending on your operating system you might
  47 need special privileges to listen on port 80.  When 0, the port will be
  48 chosen by the system the first time the acceptor is started.")
  49    (address :initarg :address
  50             :reader acceptor-address
  51             :documentation "The address the acceptor is listening on.
  52 If address is a string denoting an IP address, then the server only
  53 receives connections for that address.  This must be one of the
  54 addresses associated with the machine and allowed values are host
  55 names such as \"www.zappa.com\" and address strings such as
  56 \"72.3.247.29\".  If address is NIL, then the server will receive
  57 connections to all IP addresses on the machine. This is the default.")
  58    (name :initarg :name
  59          :accessor acceptor-name
  60          :documentation "The optional name of the acceptor, a symbol.
  61 This name can be utilized when defining \"easy handlers\" - see
  62 DEFINE-EASY-HANDLER.  The default name is an uninterned symbol as
  63 returned by GENSYM.")
  64    (request-class :initarg :request-class
  65                   :accessor acceptor-request-class
  66                   :documentation "Determines which class of request
  67 objects is created when a request comes in and should be \(a symbol
  68 naming) a class which inherits from REQUEST.  The default is the
  69 symbol REQUEST.")
  70    (reply-class :initarg :reply-class
  71                 :accessor acceptor-reply-class
  72                   :documentation "Determines which class of reply
  73 objects is created when a request is served in and should be \(a
  74 symbol naming) a class which inherits from REPLY.  The default is the
  75 symbol REPLY.")
  76    (taskmaster :initarg :taskmaster
  77                :reader acceptor-taskmaster
  78                :documentation "The taskmaster \(i.e. an instance of a
  79 subclass of TASKMASTER) that is responsible for scheduling the work
  80 for this acceptor.  The default depends on the MP capabilities of the
  81 underlying Lisp.")
  82    (output-chunking-p :initarg :output-chunking-p
  83                       :accessor acceptor-output-chunking-p
  84                       :documentation "A generalized boolean denoting
  85 whether the acceptor may use chunked encoding for output, i.e. when
  86 sending data to the client.  The default is T and there's usually no
  87 reason to change this to NIL.")
  88    (input-chunking-p :initarg :input-chunking-p
  89                      :accessor acceptor-input-chunking-p
  90                       :documentation "A generalized boolean denoting
  91 whether the acceptor may use chunked encoding for input, i.e. when
  92 accepting request bodies from the client.  The default is T and
  93 there's usually no reason to change this to NIL.")
  94    (persistent-connections-p :initarg :persistent-connections-p
  95                              :accessor acceptor-persistent-connections-p
  96                              :documentation "A generalized boolean
  97 denoting whether the acceptor supports persistent connections, which
  98 is the default for threaded acceptors.  If this property is NIL,
  99 Hunchentoot closes each incoming connection after having processed one
 100 request.  This is the default for non-threaded acceptors.")
 101    (read-timeout :initarg :read-timeout
 102                  :reader acceptor-read-timeout
 103                  :documentation "The read timeout of the acceptor,
 104 specified in \(fractional) seconds.  The precise semantics of this
 105 parameter is determined by the underlying Lisp's implementation of
 106 socket timeouts.  NIL means no timeout.")
 107    (write-timeout :initarg :write-timeout
 108                   :reader acceptor-write-timeout
 109                   :documentation "The write timeout of the acceptor,
 110 specified in \(fractional) seconds.  The precise semantics of this
 111 parameter is determined by the underlying Lisp's implementation of
 112 socket timeouts.  NIL means no timeout.")
 113    #+:lispworks
 114    (process :accessor acceptor-process
 115             :documentation "The Lisp process which accepts incoming
 116 requests.  This is the process started by COMM:START-UP-SERVER and no
 117 matter what kind of taskmaster you are using this will always be a new
 118 process different from the one where START was called.")
 119    #-:lispworks
 120    (listen-socket :initform nil
 121                   :accessor acceptor-listen-socket
 122                   :documentation "The socket listening for incoming
 123 connections.")
 124    #-:lispworks
 125    (listen-backlog :initarg :listen-backlog
 126                    :reader acceptor-listen-backlog
 127                    :documentation "Number of pending connections
 128           allowed in the listen socket before the kernel rejects
 129           further incoming connections.")
 130    (acceptor-shutdown-p :initform t
 131                         :accessor acceptor-shutdown-p
 132                         :documentation "A flag that makes the acceptor
 133 shutdown itself when set to something other than NIL.")
 134    (requests-in-progress :initform 0
 135                          :accessor acceptor-requests-in-progress
 136                          :documentation "The number of
 137 requests currently in progress.")
 138    (shutdown-queue :initform (make-condition-variable)
 139                    :accessor acceptor-shutdown-queue
 140                    :documentation "A condition variable
 141 used with soft shutdown, signaled when all requests
 142 have been processed.")
 143    (shutdown-lock :initform (make-lock "hunchentoot-acceptor-shutdown")
 144                   :accessor acceptor-shutdown-lock
 145                   :documentation "The lock protecting the shutdown-queue
 146 condition variable and the requests-in-progress counter.")
 147    (access-log-destination :initarg :access-log-destination
 148                         :accessor acceptor-access-log-destination
 149                         :documentation "Destination of the access log
 150 which contains one log entry per request handled in a format similar
 151 to Apache's access.log.  Can be set to a pathname or string
 152 designating the log file, to a open output stream or to NIL to
 153 suppress logging.")
 154    (message-log-destination :initarg :message-log-destination
 155                          :accessor acceptor-message-log-destination
 156                          :documentation "Destination of the server
 157 error log which is used to log informational, warning and error
 158 messages in a free-text format intended for human inspection. Can be
 159 set to a pathname or string designating the log file, to a open output
 160 stream or to NIL to suppress logging.")
 161    (error-template-directory :initarg :error-template-directory
 162                              :accessor acceptor-error-template-directory
 163                              :documentation "Directory pathname that
 164  contains error message template files for server-generated error
 165  messages.  Files must be named <return-code>.html with <return-code>
 166  representing the HTTP return code that the file applies to,
 167  i.e. 404.html would be used as the content for a HTTP 404 Not found
 168  response.")
 169    (document-root :initarg :document-root
 170                   :accessor acceptor-document-root
 171                   :documentation "Directory pathname that points to
 172 files that are served by the acceptor if no more specific
 173 acceptor-dispatch-request method handles the request."))
 174   (:default-initargs
 175    :address nil
 176    :port 80
 177    :name (gensym)
 178    :request-class 'request
 179    :reply-class 'reply
 180    #-lispworks :listen-backlog #-lispworks 50
 181    :taskmaster (make-instance (cond (*supports-threads-p* 'one-thread-per-connection-taskmaster)
 182                                     (t 'single-threaded-taskmaster)))
 183    :output-chunking-p t
 184    :input-chunking-p t
 185    :persistent-connections-p t
 186    :read-timeout *default-connection-timeout*
 187    :write-timeout *default-connection-timeout*
 188    :access-log-destination *error-output*
 189    :message-log-destination *error-output*
 190    :document-root (load-time-value (default-document-directory))
 191    :error-template-directory (load-time-value (default-document-directory "errors")))
 192   (:documentation "To create a Hunchentoot webserver, you make an
 193 instance of this class and use the generic function START to start it
 194 \(and STOP to stop it).  Use the :PORT initarg if you don't want to
 195 listen on the default http port 80.  There are other initargs most of
 196 which you probably won't need very often.  They are explained in
 197 detail in the docstrings of the slot definitions for this class.
 198
 199 Unless you are in a Lisp without MP capabilities, you can have several
 200 active instances of ACCEPTOR \(listening on different ports) at the
 201 same time."))
 202
 203 (defmethod print-object ((acceptor acceptor) stream)
 204   (print-unreadable-object (acceptor stream :type t)
 205     (format stream "\(host ~A, port ~A)"
 206             (or (acceptor-address acceptor) "*") (acceptor-port acceptor))))
 207
 208 (defmethod initialize-instance :after ((acceptor acceptor) &key)
 209   (with-accessors ((document-root acceptor-document-root)
 210                    (persistent-connections-p acceptor-persistent-connections-p)
 211                    (taskmaster acceptor-taskmaster)
 212                    (error-template-directory acceptor-error-template-directory)) acceptor
 213     (when (typep taskmaster
 214                  'single-threaded-taskmaster)
 215       (setf persistent-connections-p nil))
 216     (when document-root
 217       (setf document-root (translate-logical-pathname document-root)))
 218     (when error-template-directory
 219       (setf error-template-directory (translate-logical-pathname error-template-directory)))))
 220
 221 (defgeneric start (acceptor)
 222   (:documentation "Starts the ACCEPTOR so that it begins accepting
 223 connections.  Returns the acceptor."))
 224
 225 (defgeneric stop (acceptor &key soft)
 226   (:documentation "Stops the ACCEPTOR so that it no longer accepts
 227 requests.  If SOFT is true, and there are any requests in progress,
 228 wait until all requests are fully processed, but meanwhile do not
 229 accept new requests.  Note that SOFT must not be set when calling
 230 STOP from within a request handler, as that will deadlock."))
 231
 232 (defgeneric started-p (acceptor)
 233   (:documentation "Tells if ACCEPTOR has been started.
 234 The default implementation simply queries ACCEPTOR for its listening
 235 status, so if T is returned to the calling thread, then some thread
 236 has called START or some thread's call to STOP hasn't finished. If NIL
 237 is returned either some thread has called STOP, or some thread's call
 238 to START hasn't finished or START was never called at all for
 239 ACCEPTOR.")
 240   (:method (acceptor)
 241     #-lispworks (and (acceptor-listen-socket acceptor) t)
 242     #+lispworks (not (acceptor-shutdown-p acceptor))))
 243
 244 (defgeneric start-listening (acceptor)
 245   (:documentation "Sets up a listen socket for the given ACCEPTOR and
 246 enables it to listen to incoming connections.  This function is called
 247 from the thread that starts the acceptor initially and may return
 248 errors resulting from the listening operation \(like 'address in use'
 249 or similar)."))
 250
 251 (defgeneric accept-connections (acceptor)
 252   (:documentation "In a loop, accepts a connection and hands it over
 253 to the acceptor's taskmaster for processing using
 254 HANDLE-INCOMING-CONNECTION.  On LispWorks, this function returns
 255 immediately, on other Lisps it returns only once the acceptor has been
 256 stopped."))
 257
 258 (defgeneric initialize-connection-stream (acceptor stream)
 259  (:documentation "Can be used to modify the stream which is used to
 260 communicate between client and server before the request is read.  The
 261 default method of ACCEPTOR does nothing, but see for example the
 262 method defined for SSL-ACCEPTOR.  All methods of this generic function
 263 must return the stream to use."))
 264
 265 (defgeneric reset-connection-stream (acceptor stream)
 266   (:documentation "Resets the stream which is used to communicate
 267 between client and server after one request has been served so that it
 268 can be used to process the next request.  This generic function is
 269 called after a request has been processed and must return the
 270 stream."))
 271
 272 (defgeneric process-connection (acceptor socket)
 273   (:documentation "This function is called by the taskmaster when a
 274 new client connection has been established.  Its arguments are the
 275 ACCEPTOR object and a LispWorks socket handle or a usocket socket
 276 stream object in SOCKET.  It reads the request headers, sets up the
 277 request and reply objects, and hands over to PROCESS-REQUEST.  This is
 278 done in a loop until the stream has to be closed or until a connection
 279 timeout occurs.
 280
 281 It is probably not a good idea to re-implement this method until you
 282 really, really know what you're doing."))
 283
 284 (defgeneric handle-request (acceptor request)
 285   (:documentation "This function is called once the request has been
 286 read and a REQUEST object has been created.  Its job is to set up
 287 standard error handling and request logging.
 288
 289 Might be a good place for around methods specialized for your subclass
 290 of ACCEPTOR which bind or rebind special variables which can then be
 291 accessed by your handlers."))
 292
 293 (defgeneric acceptor-dispatch-request (acceptor request)
 294   (:documentation "This function is called to actually dispatch the
 295 request once the standard logging and error handling has been set up.
 296 ACCEPTOR subclasses implement methods for this function in order to
 297 perform their own request routing.  If a method does not want to
 298 handle the request, it is supposed to invoke CALL-NEXT-METHOD so that
 299 the next ACCEPTOR in the inheritance chain gets a chance to handle the
 300 request."))
 301
 302 (defgeneric acceptor-ssl-p (acceptor)
 303   (:documentation "Returns a true value if ACCEPTOR uses SSL
 304 connections.  The default is to unconditionally return NIL and
 305 subclasses of ACCEPTOR must specialize this method to signal that
 306 they're using secure connections - see the SSL-ACCEPTOR class."))
 307
 308 ;; general implementation
 309
 310 (defmethod start ((acceptor acceptor))
 311   (setf (acceptor-shutdown-p acceptor) nil)
 312   (let ((taskmaster (acceptor-taskmaster acceptor)))
 313     (setf (taskmaster-acceptor taskmaster) acceptor)
 314     (start-listening acceptor)
 315     (execute-acceptor taskmaster))
 316   acceptor)
 317
 318 (defmethod stop ((acceptor acceptor) &key soft)
 319   (with-lock-held ((acceptor-shutdown-lock acceptor))
 320     (setf (acceptor-shutdown-p acceptor) t))
 321   #-lispworks
 322   (wake-acceptor-for-shutdown acceptor)
 323   (when soft
 324     (with-lock-held ((acceptor-shutdown-lock acceptor))
 325       (when (plusp (acceptor-requests-in-progress acceptor))
 326         (condition-variable-wait (acceptor-shutdown-queue acceptor)
 327                                  (acceptor-shutdown-lock acceptor)))))
 328   (shutdown (acceptor-taskmaster acceptor))
 329   #-lispworks
 330   (usocket:socket-close (acceptor-listen-socket acceptor))
 331   #-lispworks
 332   (setf (acceptor-listen-socket acceptor) nil)
 333   #+lispworks
 334   (mp:process-kill (acceptor-process acceptor))
 335   acceptor)
 336
 337 #-lispworks
 338 (defun wake-acceptor-for-shutdown (acceptor)
 339   "Creates a dummy connection to the acceptor, waking ACCEPT-CONNECTIONS while it is waiting.
 340 This is supposed to force a check of ACCEPTOR-SHUTDOWN-P."
 341   (handler-case
 342       (multiple-value-bind (address port) (usocket:get-local-name (acceptor-listen-socket acceptor))
 343         (let ((conn (usocket:socket-connect address port)))
 344           (usocket:socket-close conn)))
 345     (error (e)
 346       (acceptor-log-message acceptor :error "Wake-for-shutdown connect failed: ~A" e))))
 347
 348 (defmethod initialize-connection-stream ((acceptor acceptor) stream)
 349  ;; default method does nothing
 350  stream)
 351
 352 (defmethod reset-connection-stream ((acceptor acceptor) stream)
 353   ;; turn chunking off at this point
 354   (cond ((typep stream 'chunked-stream)
 355          ;; flush the stream first and check if there's unread input
 356          ;; which would be an error
 357          (setf (chunked-stream-output-chunking-p stream) nil
 358                (chunked-stream-input-chunking-p stream) nil)
 359          ;; switch back to bare socket stream
 360          (chunked-stream-stream stream))
 361         (t stream)))
 362
 363 (defmethod process-connection :around ((*acceptor* acceptor) (socket t))
 364   ;; this around method is used for error handling
 365   ;; note that this method also binds *ACCEPTOR*
 366   (with-conditions-caught-and-logged ()
 367     (with-mapped-conditions ()
 368       (call-next-method))))
 369
 370 (defun do-with-acceptor-request-count-incremented (*acceptor* function)
 371   (with-lock-held ((acceptor-shutdown-lock *acceptor*))
 372     (incf (acceptor-requests-in-progress *acceptor*)))
 373   (unwind-protect
 374        (funcall function)
 375     (with-lock-held ((acceptor-shutdown-lock *acceptor*))
 376       (decf (acceptor-requests-in-progress *acceptor*))
 377       (when (acceptor-shutdown-p *acceptor*)
 378         (condition-variable-signal (acceptor-shutdown-queue *acceptor*))))))
 379
 380 (defmacro with-acceptor-request-count-incremented ((acceptor) &body body)
 381   "Execute BODY with ACCEPTOR-REQUESTS-IN-PROGRESS of ACCEPTOR
 382   incremented by one.  If the ACCEPTOR-SHUTDOWN-P returns true after
 383   the BODY has been executed, the ACCEPTOR-SHUTDOWN-QUEUE condition
 384   variable of the ACCEPTOR is signalled in order to finish shutdown
 385   processing."
 386   `(do-with-acceptor-request-count-incremented ,acceptor (lambda () ,@body)))
 387
 388 (defun acceptor-make-request (acceptor socket
 389                               &key
 390                                   headers-in
 391                                   content-stream
 392                                   method
 393                                   uri
 394                                   remote
 395                                   local
 396                                   server-protocol)
 397   "Make a REQUEST instance for the ACCEPTOR, setting up those slots
 398   that are determined from the SOCKET by calling the appropriate
 399   socket query functions."
 400   (multiple-value-bind (remote-addr remote-port)
 401       (if remote
 402           (values-list remote)
 403           (get-peer-address-and-port socket))
 404     (multiple-value-bind (local-addr local-port)
 405         (if local
 406             (values-list local)
 407             (get-local-address-and-port socket))
 408       (make-instance (acceptor-request-class acceptor)
 409                      :acceptor acceptor
 410                      :local-addr local-addr
 411                      :local-port local-port
 412                      :remote-addr remote-addr
 413                      :remote-port remote-port
 414                      :headers-in headers-in
 415                      :content-stream content-stream
 416                      :method method
 417                      :uri uri
 418                      :server-protocol server-protocol))))
 419
 420 (defgeneric detach-socket (acceptor)
 421   (:documentation "Indicate to Hunchentoot that it should stop serving
 422                    requests on the current request's socket.
 423                    Hunchentoot will finish processing the current
 424                    request and then return from PROCESS-CONNECTION
 425                    without closing the connection to the client.
 426                    DETACH-SOCKET can only be called from within a
 427                    request handler function."))
 428
 429 (defmethod detach-socket ((acceptor acceptor))
 430   (setf *finish-processing-socket* t
 431         *close-hunchentoot-stream* nil))
 432
 433 (defmethod process-connection ((*acceptor* acceptor) (socket t))
 434   (let* ((socket-stream (make-socket-stream socket *acceptor*))
 435          (*hunchentoot-stream*)
 436          (*close-hunchentoot-stream* t)
 437          (remote (multiple-value-list (get-peer-address-and-port socket)))
 438          (local (multiple-value-list (get-local-address-and-port socket))))
 439     (unwind-protect
 440          ;; process requests until either the acceptor is shut down,
 441          ;; *CLOSE-HUNCHENTOOT-STREAM* has been set to T by the
 442          ;; handler, or the peer fails to send a request
 443          (progn
 444            (setq *hunchentoot-stream* (initialize-connection-stream *acceptor* socket-stream))
 445            (loop
 446               (let ((*finish-processing-socket* t))
 447                 (when (acceptor-shutdown-p *acceptor*)
 448                   (return))
 449                 (multiple-value-bind (headers-in method url-string protocol)
 450                     (get-request-data *hunchentoot-stream*)
 451                   ;; check if there was a request at all
 452                   (unless method
 453                     (return))
 454                   ;; bind per-request special variables, then process the
 455                   ;; request - note that *ACCEPTOR* was bound above already
 456                   (let ((*reply* (make-instance (acceptor-reply-class *acceptor*)))
 457                         (*session* nil)
 458                         (transfer-encodings (cdr (assoc* :transfer-encoding headers-in))))
 459                     (when transfer-encodings
 460                       (setq transfer-encodings
 461                             (split "\\s*,\\s*" transfer-encodings))
 462                       (when (member "chunked" transfer-encodings :test #'equalp)
 463                         (cond ((acceptor-input-chunking-p *acceptor*)
 464                                ;; turn chunking on before we read the request body
 465                                (setf *hunchentoot-stream* (make-chunked-stream *hunchentoot-stream*)
 466                                      (chunked-stream-input-chunking-p *hunchentoot-stream*) t))
 467                               (t (hunchentoot-error "Client tried to use ~
 468 chunked encoding, but acceptor is configured to not use it.")))))
 469                     (with-acceptor-request-count-incremented (*acceptor*)
 470                       (process-request (acceptor-make-request *acceptor* socket
 471                                                               :headers-in headers-in
 472                                                               :content-stream *hunchentoot-stream*
 473                                                               :method method
 474                                                               :uri url-string
 475                                                               :remote remote
 476                                                               :local local
 477                                                               :server-protocol protocol))))
 478                   (finish-output *hunchentoot-stream*)
 479                   (setq *hunchentoot-stream* (reset-connection-stream *acceptor* *hunchentoot-stream*))
 480                   (when *finish-processing-socket*
 481                     (return))))))
 482       (when *close-hunchentoot-stream*
 483         (flet ((close-stream (stream)
 484                  ;; as we are at the end of the request here, we ignore all
 485                  ;; errors that may occur while flushing and/or closing the
 486                  ;; stream.
 487                  (ignore-errors
 488                   (finish-output stream))
 489                  (ignore-errors
 490                   (close stream :abort t))))
 491           (unless (or (not *hunchentoot-stream*)
 492                       (eql socket-stream *hunchentoot-stream*))
 493             (close-stream *hunchentoot-stream*))
 494           (close-stream socket-stream))))))
 495
 496 (defmethod acceptor-ssl-p ((acceptor t))
 497   ;; the default is to always answer "no"
 498   nil)
 499
 500 (defgeneric acceptor-log-access (acceptor &key return-code)
 501   (:documentation
 502    "Function to call to log access to the acceptor.  The RETURN-CODE,
 503 CONTENT and CONTENT-LENGTH keyword arguments contain additional
 504 information about the request to log.  In addition, it can use the
 505 standard request accessor functions that are available to handler
 506 functions to find out more information about the request."))
 507
 508 (defmethod acceptor-log-access ((acceptor acceptor) &key return-code)
 509   "Default method for access logging.  It logs the information to the
 510 destination determined by (ACCEPTOR-ACCESS-LOG-DESTINATION ACCEPTOR)
 511 \(unless that value is NIL) in a format that can be parsed by most
 512 Apache log analysis tools.)"
 513
 514   (with-log-stream (stream (acceptor-access-log-destination acceptor) *access-log-lock*)
 515     (format stream "~:[-~@[ (~A)~]~;~:*~A~@[ (~A)~]~] ~:[-~;~:*~A~] [~A] \"~A ~A~@[?~A~] ~
 516                     ~A\" ~D ~:[-~;~:*~D~] \"~:[-~;~:*~A~]\" \"~:[-~;~:*~A~]\"~%"
 517             (remote-addr*)
 518             (header-in* :x-forwarded-for)
 519             (authorization)
 520             (iso-time)
 521             (request-method*)
 522             (script-name*)
 523             (query-string*)
 524             (server-protocol*)
 525             return-code
 526             (content-length*)
 527             (referer)
 528             (user-agent))))
 529
 530 (defgeneric acceptor-log-message (acceptor log-level format-string &rest format-arguments)
 531   (:documentation
 532    "Function to call to log messages by the ACCEPTOR.  It must accept
 533 a severity level for the message, which will be one of :ERROR, :INFO,
 534 or :WARNING, a format string and an arbitary number of formatting
 535 arguments."))
 536
 537 (defmethod acceptor-log-message ((acceptor acceptor) log-level format-string &rest format-arguments)
 538   "Default function to log server messages.  Sends a formatted message
 539   to the destination denoted by (ACCEPTOR-MESSAGE-LOG-DESTINATION
 540   ACCEPTOR).  FORMAT and ARGS are as in FORMAT.  LOG-LEVEL is a
 541   keyword denoting the log level or NIL in which case it is ignored."
 542   (with-log-stream (stream (acceptor-message-log-destination acceptor) *message-log-lock*)
 543     (handler-case
 544         (format stream "[~A~@[ [~A]~]] ~?~%"
 545                 (iso-time) log-level
 546                 format-string format-arguments)
 547       (error (e)
 548         (ignore-errors
 549          (format *trace-output* "error ~A while writing to error log, error not logged~%" e))))))
 550
 551 (defun log-message* (log-level format-string &rest format-arguments)
 552   "Convenience function which calls the message logger of the current
 553 acceptor \(if there is one) with the same arguments it accepts.
 554
 555 This is the function which Hunchentoot itself uses to log errors it
 556 catches during request processing."
 557   (apply 'acceptor-log-message *acceptor* log-level format-string format-arguments))
 558
 559 ;; usocket implementation
 560
 561 #-:lispworks
 562 (defmethod start-listening ((acceptor acceptor))
 563   (when (acceptor-listen-socket acceptor)
 564     (hunchentoot-error "acceptor ~A is already listening" acceptor))
 565   (setf (acceptor-listen-socket acceptor)
 566         (usocket:socket-listen (or (acceptor-address acceptor)
 567                                    usocket:*wildcard-host*)
 568                                (acceptor-port acceptor)
 569                                :reuseaddress t
 570                                :backlog (acceptor-listen-backlog acceptor)
 571                                :element-type '(unsigned-byte 8)))
 572   (values))
 573
 574 #-:lispworks
 575 (defmethod start-listening :after ((acceptor acceptor))
 576   (when (zerop (acceptor-port acceptor))
 577     (setf (slot-value acceptor 'port) (usocket:get-local-port (acceptor-listen-socket acceptor)))))
 578
 579 #-:lispworks
 580 (defmethod accept-connections ((acceptor acceptor))
 581   (usocket:with-server-socket (listener (acceptor-listen-socket acceptor))
 582     (loop
 583       (with-lock-held ((acceptor-shutdown-lock acceptor))
 584         (when (acceptor-shutdown-p acceptor)
 585           (return)))
 586       (when (usocket:wait-for-input listener :ready-only t)
 587        (when-let (client-connection
 588                   (handler-case (usocket:socket-accept listener)
 589                     ;; ignore condition
 590                     (usocket:connection-aborted-error ())))
 591          (set-timeouts client-connection
 592                        (acceptor-read-timeout acceptor)
 593                        (acceptor-write-timeout acceptor))
 594          (handle-incoming-connection (acceptor-taskmaster acceptor)
 595                                      client-connection))))))
 596
 597 ;; LispWorks implementation
 598
 599 #+:lispworks
 600 (defmethod start-listening ((acceptor acceptor))
 601   (multiple-value-bind (listener-process startup-condition)
 602       (comm:start-up-server :service (acceptor-port acceptor)
 603                             :address (acceptor-address acceptor)
 604                             :process-name (format nil "Hunchentoot listener \(~A:~A)"
 605                                                   (or (acceptor-address acceptor) "*")
 606                                                   (acceptor-port acceptor))
 607                             ;; this function is called once on startup - we
 608                             ;; use it to check for errors and random port
 609                             :announce (lambda (socket &optional condition)
 610                                         (when condition
 611                                           (error condition))
 612                                         (when (or (null (acceptor-port acceptor))
 613                                                   (zerop (acceptor-port acceptor)))
 614                                           (multiple-value-bind (address port)
 615                                               (comm:get-socket-address socket)
 616                                             (declare (ignore address))
 617                                             (setf (slot-value acceptor 'port) port))))
 618                             ;; this function is called whenever a connection
 619                             ;; is made
 620                             :function (lambda (handle)
 621                                         (unless (acceptor-shutdown-p acceptor)
 622                                           (handle-incoming-connection
 623                                            (acceptor-taskmaster acceptor) handle)))
 624                             ;; wait until the acceptor was successfully started
 625                             ;; or an error condition is returned
 626                             :wait t)
 627     (when startup-condition
 628       (error startup-condition))
 629     (mp:process-stop listener-process)
 630     (setf (acceptor-process acceptor) listener-process)
 631     (values)))
 632
 633 #+:lispworks
 634 (defmethod accept-connections ((acceptor acceptor))
 635   (mp:process-unstop (acceptor-process acceptor))
 636   nil)
 637
 638 (defmethod acceptor-dispatch-request ((acceptor acceptor) request)
 639   "Detault implementation of the request dispatch method, generates an
 640 +http-not-found+ error."
 641   (let ((path (and (acceptor-document-root acceptor)
 642                    (request-pathname request))))
 643     (cond
 644       (path
 645        (handle-static-file
 646         (merge-pathnames (if (equal "/" (script-name request)) #p"index.html" path)
 647                          (acceptor-document-root acceptor))))
 648       (t
 649        (setf (return-code *reply*) +http-not-found+)
 650        (abort-request-handler)))))
 651
 652 (defmethod handle-request ((*acceptor* acceptor) (*request* request))
 653   "Standard method for request handling.  Calls the request dispatcher
 654 of *ACCEPTOR* to determine how the request should be handled.  Also
 655 sets up standard error handling which catches any errors within the
 656 handler."
 657   (handler-bind ((error
 658                   (lambda (cond)
 659                     ;; if the headers were already sent, the error
 660                     ;; happened within the body and we have to close
 661                     ;; the stream
 662                     (when *headers-sent*
 663                       (setq *finish-processing-socket* t))
 664                     (throw 'handler-done
 665                       (values nil cond (get-backtrace))))))
 666     (with-debugger
 667       (acceptor-dispatch-request *acceptor* *request*))))
 668
 669 (defgeneric acceptor-status-message (acceptor http-status-code &key &allow-other-keys)
 670   (:documentation
 671    "This function is called after the request's handler has been
 672    invoked to convert the HTTP-STATUS-CODE to a HTML message to be
 673    displayed to the user.  If this function returns a string, that
 674    string is sent to the client instead of the content produced by the
 675    handler, if any.
 676
 677    If an ERROR-TEMPLATE-DIRECTORY is set in the current acceptor and
 678    the directory contains a file corresponding to HTTP-STATUS-CODE
 679    named <code>.html, that file is sent to the client after variable
 680    substitution.  Variables are referenced by ${<variable-name>}.
 681
 682    Additional keyword arguments may be provided which are made
 683    available to the templating logic as substitution variables.  These
 684    variables can be interpolated into error message templates in,
 685    which contains the current URL relative to the server and without
 686    GET parameters.
 687
 688    In addition to the variables corresponding to keyword arguments,
 689    the script-name, lisp-implementation-type,
 690    lisp-implementation-version and hunchentoot-version variables are
 691    available."))
 692
 693 (defun make-cooked-message (http-status-code &key error backtrace)
 694   (labels ((cooked-message (format &rest arguments)
 695              (setf (content-type*) "text/html; charset=iso-8859-1")
 696              (format nil "<html><head><title>~D ~A</title></head><body><h1>~:*~A</h1>~?<p><hr>~A</p></body></html>"
 697                      http-status-code (reason-phrase http-status-code)
 698                      format (mapcar (lambda (arg)
 699                                       (if (stringp arg)
 700                                           (escape-for-html arg)
 701                                           arg))
 702                                     arguments)
 703                      (address-string))))
 704     (case http-status-code
 705       ((#.+http-moved-temporarily+
 706         #.+http-moved-permanently+)
 707        (cooked-message "The document has moved <a href='~A'>here</a>" (header-out :location)))
 708       ((#.+http-authorization-required+)
 709        (cooked-message "The server could not verify that you are authorized to access the document requested.  ~
 710                         Either you supplied the wrong credentials \(e.g., bad password), or your browser doesn't ~
 711                         understand how to supply the credentials required."))
 712       ((#.+http-forbidden+)
 713        (cooked-message "You don't have permission to access ~A on this server."
 714                        (script-name *request*)))
 715       ((#.+http-not-found+)
 716        (cooked-message "The requested URL ~A was not found on this server."
 717                        (script-name *request*)))
 718       ((#.+http-bad-request+)
 719        (cooked-message "Your browser sent a request that this server could not understand."))
 720       ((#.+http-internal-server-error+)
 721        (if *show-lisp-errors-p*
 722            (cooked-message "<pre>~A~@[~%~%Backtrace:~%~%~A~]</pre>"
 723                            (escape-for-html (princ-to-string error))
 724                            (when *show-lisp-backtraces-p*
 725                              (escape-for-html (princ-to-string backtrace))))
 726            (cooked-message "An error has occurred")))
 727       (t
 728          (when (<= 400 http-status-code)
 729            (cooked-message "An error has occurred"))))))
 730
 731 (defmethod acceptor-status-message ((acceptor t) http-status-code &rest args &key &allow-other-keys)
 732   (apply 'make-cooked-message http-status-code args))
 733
 734 (defmethod acceptor-status-message :around ((acceptor acceptor) http-status-code &rest args &key &allow-other-keys)
 735   (handler-case
 736       (call-next-method)
 737     (error (e)
 738       (log-message* :error "error ~A during error processing, sending cooked message to client" e)
 739       (apply 'make-cooked-message http-status-code args))))
 740
 741 (defun string-as-keyword (string)
 742   "Intern STRING as keyword using the reader so that case conversion is done with the reader defaults."
 743   (let ((*package* (find-package :keyword)))
 744     (read-from-string string)))
 745
 746 (defmethod acceptor-status-message ((acceptor acceptor) http-status-code &rest properties &key &allow-other-keys)
 747   "Default function to generate error message sent to the client."
 748   (labels
 749       ((substitute-request-context-variables (string)
 750          (let ((properties (append `(:script-name ,(script-name*)
 751                                      :lisp-implementation-type ,(lisp-implementation-type)
 752                                      :lisp-implementation-version ,(lisp-implementation-version)
 753                                      :hunchentoot-version ,*hunchentoot-version*)
 754                                    properties)))
 755            (unless *show-lisp-backtraces-p*
 756              (setf (getf properties :backtrace) nil))
 757            (cl-ppcre:regex-replace-all "(?i)\\$\\{([a-z0-9-_]+)\\}"
 758                                        string
 759                                        (lambda (target-string start end match-start match-end reg-starts reg-ends)
 760                                          (declare (ignore start end match-start match-end))
 761                                          (let ((variable-name (string-as-keyword (subseq target-string
 762                                                                                          (aref reg-starts 0)
 763                                                                                          (aref reg-ends 0)))))
 764                                            (escape-for-html (princ-to-string (getf properties variable-name variable-name))))))))
 765        (file-contents (file)
 766          (let ((buf (make-string (file-length file))))
 767            (read-sequence buf file)
 768            buf))
 769        (error-contents-from-template ()
 770          (let ((error-file-template-pathname (and (acceptor-error-template-directory acceptor)
 771                                                   (probe-file (make-pathname :name (princ-to-string http-status-code)
 772                                                                              :type "html"
 773                                                                              :defaults (acceptor-error-template-directory acceptor))))))
 774            (when error-file-template-pathname
 775              (with-open-file (file error-file-template-pathname :if-does-not-exist nil :element-type 'character)
 776                (when file
 777                  (setf (content-type*) "text/html")
 778                  (substitute-request-context-variables (file-contents file))))))))
 779     (or (unless (< 300 http-status-code)
 780           (call-next-method))              ; don't ever try template for positive return codes
 781         (when *show-lisp-errors-p*
 782           (error-contents-from-template))  ; try template
 783         (call-next-method))))              ; fall back to cooked message
 784
 785 (defgeneric acceptor-remove-session (acceptor session)
 786   (:documentation
 787    "This function is called whenever a session in ACCEPTOR is being
 788    destroyed because of a session timout or an explicit REMOVE-SESSION
 789    call."))
 790
 791 (defmethod acceptor-remove-session ((acceptor acceptor) (session t))
 792   "Default implementation for the session removal hook function.  This
 793 function is called whenever a session is destroyed."
 794   nil)
 795
 796 (defgeneric acceptor-server-name (acceptor)
 797   (:documentation "Returns a string which can be used for 'Server' headers.")
 798   (:method ((acceptor acceptor))
 799     (format nil "Hunchentoot ~A" *hunchentoot-version*)))