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;;; Web I/O: HTTP
;; Copyright (C) 2010, 2011, 2012, 2015 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 HTTP implementation of the (web server) interface.
;;;
;;; `read-request' sets the character encoding on the new port to
;;; latin-1. See the note in request.scm regarding character sets,
;;; strings, and bytevectors for more information.
;;;
;;; Code:
(define-module (web server http)
#:use-module ((srfi srfi-1) #:select (fold))
#:use-module (srfi srfi-9)
#:use-module (rnrs bytevectors)
#:use-module (web request)
#:use-module (web response)
#:use-module (web server)
#:use-module (ice-9 poll)
#:export (http))
(define (make-default-socket family addr port)
(let ((sock (socket PF_INET SOCK_STREAM 0)))
(setsockopt sock SOL_SOCKET SO_REUSEADDR 1)
(bind sock family addr port)
sock))
(define-record-type <http-server>
(make-http-server socket poll-idx poll-set)
http-server?
(socket http-socket)
(poll-idx http-poll-idx set-http-poll-idx!)
(poll-set http-poll-set))
(define *error-events* (logior POLLHUP POLLERR))
(define *read-events* POLLIN)
(define *events* (logior *error-events* *read-events*))
;; -> server
(define* (http-open #:key
(host #f)
(family AF_INET)
(addr (if host
(inet-pton family host)
INADDR_LOOPBACK))
(port 8080)
(socket (make-default-socket family addr port)))
(listen socket 128)
(sigaction SIGPIPE SIG_IGN)
(let ((poll-set (make-empty-poll-set)))
(poll-set-add! poll-set socket *events*)
(make-http-server socket 0 poll-set)))
(define (bad-request port)
(write-response (build-response #:version '(1 . 0) #:code 400
#:headers '((content-length . 0)))
port))
;; -> (client request body | #f #f #f)
(define (http-read server)
(let* ((poll-set (http-poll-set server)))
(let lp ((idx (http-poll-idx server)))
(let ((revents (poll-set-revents poll-set idx)))
(cond
((zero? idx)
;; The server socket, and the end of our downward loop.
(cond
((zero? revents)
;; No client ready, and no error; poll and loop.
(poll poll-set)
(lp (1- (poll-set-nfds poll-set))))
((not (zero? (logand revents *error-events*)))
;; An error.
(set-http-poll-idx! server idx)
(throw 'interrupt))
(else
;; A new client. Add to set, poll, and loop.
;;
;; FIXME: preserve meta-info.
(let ((client (accept (poll-set-port poll-set idx))))
;; Buffer input and output on this port.
(setvbuf (car client) 'block)
;; From "HOP, A Fast Server for the Diffuse Web", Serrano.
(setsockopt (car client) SOL_SOCKET SO_SNDBUF (* 12 1024))
(poll-set-add! poll-set (car client) *events*)
(poll poll-set)
(lp (1- (poll-set-nfds poll-set)))))))
((zero? revents)
;; Nothing on this port.
(lp (1- idx)))
;; Otherwise, a client socket with some activity on
;; it. Remove it from the poll set.
(else
(let ((port (poll-set-remove! poll-set idx)))
;; Record the next index in all cases, in case the EOF check
;; throws an error.
(set-http-poll-idx! server (1- idx))
(cond
((eof-object? (peek-char port))
;; EOF.
(close-port port)
(lp (1- idx)))
(else
;; Otherwise, try to read a request from this port.
(with-throw-handler
#t
(lambda ()
(let ((req (read-request port)))
(values port
req
(read-request-body req))))
(lambda (k . args)
(define-syntax-rule (cleanup-catch statement)
(catch #t
(lambda () statement)
(lambda (k . args)
(format (current-error-port) "In ~a:\n" 'statement)
(print-exception (current-error-port) #f k args))))
(cleanup-catch (bad-request port))
(cleanup-catch (close-port port)))))))))))))
(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)))))
;; -> 0 values
(define (http-write server client response body)
(let* ((response (write-response response client))
(port (response-port response)))
(cond
((not body)) ; pass
((bytevector? body)
(write-response-body response body))
(else
(error "Expected a bytevector for body" body)))
(cond
((keep-alive? response)
(force-output port)
(poll-set-add! (http-poll-set server) port *events*))
(else
(close-port port)))
(values)))
;; -> unspecified values
(define (http-close server)
(let ((poll-set (http-poll-set server)))
(let lp ((n (poll-set-nfds poll-set)))
(if (positive? n)
(begin
(close-port (poll-set-remove! poll-set (1- n)))
(lp (1- n)))))))
(define-server-impl http
http-open
http-read
http-write
http-close)
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