racket/collects/handin-server/run-servlet.rkt

116 lines
4.3 KiB
Racket

#lang racket/base
(define default-context-length (error-print-context-length))
;; This code has parts that are copied from `serve/servlet' in
;; "web-server/servlet-env.rkt", and parts from `serve/launch/wait' in
;; "web-server/servlet-dispatch.rkt"
(require racket/unit
racket/async-channel
web-server/web-server
web-server/servlet-dispatch
web-server/managers/lru
(prefix-in sequencer: web-server/dispatchers/dispatch-sequencer)
(prefix-in log: web-server/dispatchers/dispatch-log)
web-server/http/request-structs
net/url
openssl
net/tcp-sig)
;; maps ports to the underlying ssl ports (could be done with `prop:*-port')
(define port->ssl (make-weak-hasheq))
;; wrap a port so that the semaphore is posted to when it's closed
(define (wrap-with-closing-sema outp sema)
(make-output-port
(object-name outp) outp
(lambda (buf start end nonblock? breakable?)
((if nonblock?
write-bytes-avail*
(if breakable?
write-bytes-avail/enable-break
write-bytes-avail))
buf outp start end))
(lambda ()
(close-output-port outp)
(semaphore-post sema))))
;; creates a tcp unit that grabs connections from the async-channel, each
;; connection is passed as a list holding an input port, an output port, and a
;; semaphore that should be posted to when the connection is done.
(define (make-tcp@ ach)
(unit (import) (export tcp^)
(define (tcp-accept . _)
(define-values [inp outp sema] (apply values (async-channel-get ach)))
(define outp* (wrap-with-closing-sema outp sema))
(hash-set! port->ssl outp* outp)
(values inp outp*))
(define tcp-accept/enable-break tcp-accept)
(define (tcp-accept-ready? l)
;; FIXME: need to peek into the channel
#t)
(define (tcp-abandon-port p)
(ssl-abandon-port (hash-ref port->ssl p p)))
(define (tcp-addresses p [port-numbers? #f])
(if (void? p) ;; from listen!
(if port-numbers?
(values "localhost" "0.0.0.0" 1 1)
(values "localhost" "0.0.0.0"))
(ssl-addresses (hash-ref port->ssl p p) port-numbers?)))
;; prevent the server from actually listening:
(define tcp-close void)
(define tcp-listen void)
(define tcp-listener? void?)
(define tcp-connect void)
(define tcp-connect/enable-break void)))
(provide run-servlet)
(define (run-servlet dispatcher
#:log-file [log-file #f])
;; a channel for incoming requests
(define ach (make-async-channel))
;; wrap the dispatcher so we can post on the waiting semaphore
(define (wrap-sequence . ds)
(let* ([ds (filter values ds)] ;; drop #f when log-file is #f
[d (apply sequencer:make ds)])
(lambda (conn req)
(d conn req)
;; (cond [(hash-ref port->sema (connection-o-port conn) #f)
;; => semaphore-post])
)))
;; error handler that redirects back to where the interaction started
(define ((send-error msg to) req)
(let ([to (to)])
`(html (head (meta ([http-equiv "refresh"]
[content ,(format "3;URL=~a" to)]))
(title ,msg))
(body ,msg "; " (a ([href ,to]) "restarting") " in 3 seconds."))))
(define shut
(serve
#:tcp@ (make-tcp@ ach)
#:dispatch
(wrap-sequence
(and log-file (log:make #:format (log:log-format->format 'apache-default)
#:log-path log-file))
(let ([init-path (make-parameter "/")])
(dispatch/servlet
(lambda (req)
(init-path (url->string (request-uri req)))
(dispatcher req))
#:regexp #rx""
#:manager (make-threshold-LRU-manager
(send-error "Your session has expired" init-path)
(* 12 1024 1024))))
;; This can be used to serve html content too; doesn't make sense now,
;; since the servlet will be used for all requests, and it never calls
;; (next-dispatcher). (See "servlet-env.rkt" for the needed `require's.)
;; (files:make
;; #:url->path (fsmap:make-url->path (build-path server-dir "htdocs")))
;; (lift:make (send-error "File not found" (lambda () "/")))
)))
(lambda (msg . args)
(case msg
[(shutdown) (shut)]
[(connect) (async-channel-put ach args)])))