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;;; Web I/O: Non-blocking HTTP
;; Copyright (C) 2012, 2018 Free Software Foundation, Inc.
;; This library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public
;; License as published by the Free Software Foundation; either
;; version 3 of the License, or (at your option) any later version.
;;
;; This library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; Lesser General Public License for more details.
;;
;; You should have received a copy of the GNU Lesser General Public
;; License along with this library; if not, write to the Free Software
;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
;; 02110-1301 USA
;;; Commentary:
;;;
;;; This is the non-blocking HTTP implementation of the (web server)
;;; interface.
;;;
;;; It is a modified version of (web server fibers) from Fibers 1.0.0 that
;;; does not create new threads and does not call 'run-fibers'. Instead it
;;; expects to be running directly in a fiberized program.
;;;
;;; (Modifications by Ludovic Courtès, 2018-01.)
;;;
;;; Code:
(define-module (web server fiberized)
#:use-module ((srfi srfi-1) #:select (fold))
#:use-module (srfi srfi-9)
#:use-module (web http)
#:use-module (web request)
#:use-module (web response)
#:use-module (web server)
#:use-module (ice-9 binary-ports)
#:use-module (ice-9 match)
#:use-module (fibers)
#:use-module (fibers channels)
#:use-module (cuirass logging))
(define (make-default-socket family addr port)
(let ((sock (socket PF_INET SOCK_STREAM 0)))
(setsockopt sock SOL_SOCKET SO_REUSEADDR 1)
(fcntl sock F_SETFD FD_CLOEXEC)
(bind sock family addr port)
(fcntl sock F_SETFL (logior O_NONBLOCK (fcntl sock F_GETFL)))
sock))
(define-record-type <server>
(make-server request-channel)
server?
(request-channel server-request-channel))
;; -> server
(define* (open-server #:key
(host #f)
(family AF_INET)
(addr (if host
(inet-pton family host)
INADDR_LOOPBACK))
(port 8080)
(socket (make-default-socket family addr port)))
;; We use a large backlog by default. If the server is suddenly hit
;; with a number of connections on a small backlog, clients won't
;; receive confirmation for their SYN, leading them to retry --
;; probably successfully, but with a large latency.
(listen socket 1024)
(fcntl socket F_SETFL (logior O_NONBLOCK (fcntl socket F_GETFL)))
(sigaction SIGPIPE SIG_IGN)
(let ((request-channel (make-channel)))
(spawn-fiber
(lambda ()
(socket-loop socket request-channel)))
(make-server request-channel)))
(define (bad-request msg . args)
(throw 'bad-request msg args))
(define (keep-alive? response)
(let ((v (response-version response)))
(and (or (< (response-code response) 400)
(= (response-code response) 404))
(case (car v)
((1)
(case (cdr v)
((1) (not (memq 'close (response-connection response))))
((0) (memq 'keep-alive (response-connection response)))))
(else #f)))))
(define (client-loop client have-request)
;; Always disable Nagle's algorithm, as we handle buffering
;; ourselves.
(setsockopt client IPPROTO_TCP TCP_NODELAY 1)
(setvbuf client 'block 1024)
(with-throw-handler #t
(lambda ()
(let ((response-channel (make-channel)))
(let loop ()
(cond
((eof-object? (lookahead-u8 client))
(close-port client))
(else
(call-with-values
(lambda ()
(catch #t
(lambda ()
(let* ((request (read-request client))
(body (read-request-body request)))
(have-request response-channel request body)))
(lambda (key . args)
(display "While reading request:\n" (current-error-port))
(print-exception (current-error-port) #f key args)
(values (build-response #:version '(1 . 0) #:code 400
#:headers '((content-length . 0)))
#vu8()))))
(lambda (response body)
(write-response response client)
(when body
(put-bytevector client body))
(force-output client)
(if (and (keep-alive? response)
(not (eof-object? (peek-char client))))
(loop)
(close-port client)))))))))
(lambda (k . args)
(catch #t
(lambda () (close-port client))
(lambda (k . args)
(display "While closing port:\n" (current-error-port))
(print-exception (current-error-port) #f k args))))))
(define (socket-loop socket request-channel)
(define (have-request response-channel request body)
(put-message request-channel (vector response-channel request body))
(match (get-message response-channel)
(#(response body)
(values response body))))
(let loop ()
(match (accept socket (logior SOCK_NONBLOCK SOCK_CLOEXEC))
((client . sockaddr)
(log-message "HTTP connection from ~a"
(inet-ntop (sockaddr:fam sockaddr)
(sockaddr:addr sockaddr)))
(spawn-fiber (lambda () (client-loop client have-request))
#:parallel? #t)
(loop)))))
;; -> (client request body | #f #f #f)
(define (server-read server)
(match (get-message (server-request-channel server))
(#(response-channel request body)
(let ((client response-channel))
(values client request body)))))
;; -> 0 values
(define (server-write server client response body)
(let ((response-channel client))
(put-message response-channel (vector response body)))
(values))
;; -> unspecified values
(define (close-server server)
;; FIXME: We should terminate the 'socket-loop' fiber somehow.
*unspecified*)
(define-server-impl fiberized
open-server
server-read
server-write
close-server)
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