--- /dev/null
+;;; Imports
+
+;; Chicken 5
+(import (chicken tcp)
+ (chicken port)
+ (chicken io)
+ (chicken string)
+ (chicken pathname)
+ (chicken file posix)
+ (chicken time posix)
+ (chicken condition)
+ (chicken process)
+ (chicken process-context)
+ srfi-1 srfi-13 matchable)
+
+;; Chicken 4
+;; (use srfi-1 srfi-13 tcp posix matchable)
+
+;;; Global constants
+
+(define gopher-index-file-name "index")
+
+(define burrower-version "1.0.0")
+
+(define burrower-footer
+ (conc "\n"
+ "--------------------------------------------------\n"
+ "This gopher hole was dug using Burrower v" burrower-version "\n"
+ "Powered by Chicken Scheme!"))
+
+
+;;; Server loop
+
+;; We don't yet use worker threads here to handle requests,
+;; the server just blocks until the first request is finished.
+;; While we should fix this, it's actually probably okay, as
+;; we genuinely don't expect a huge flood of gopher traffic. :-(
+
+(define-record config root-dir host port display-footer)
+
+(define (run-server config)
+ (print "Gopher server listening on port " (config-port config) " ...")
+ (let ((listener (tcp-listen (config-port config))))
+ (let server-loop ()
+ (let-values (((in-port out-port) (tcp-accept listener)))
+ (let* ((line (read-line in-port))
+ (selector (string-trim-both line)))
+ (let-values (((local-ip remote-ip) (tcp-addresses in-port)))
+ (print "Accepted connection from " remote-ip
+ " on " (seconds->string))
+ (condition-case
+ (begin
+ (with-output-to-port out-port
+ (lambda ()
+ (serve-selector (if (= (string-length selector) 0)
+ "/"
+ selector)
+ remote-ip config)))
+ (print "... served selector '" selector "'. Closing connection."))
+ (o (exn)
+ (print-error-message o out-port)
+ (print-error-message o)
+ (print "Error while attempting to serve selector " selector ".")))))
+ (close-input-port in-port)
+ (close-output-port out-port))
+ (server-loop))
+ (tcp-close listener)))
+
+
+;;; Selector type inference
+
+(define (has-suffix? selector . suffixes)
+ (if (null? suffixes)
+ #f
+ (if (string-suffix? (car suffixes) selector)
+ #t
+ (apply has-suffix? selector (cdr suffixes)))))
+
+(define (infer-selector-type selector)
+ (let ((l (string-downcase selector)))
+ (cond
+ ((or (= (string-length l) 0) (string-suffix? "/" l)) 1)
+ ((has-suffix? l ".txt" ".org" ".md") 0)
+ ((has-suffix? l ".png" ".jpg" ".gif" ".bmp" ".tif" ".tga") 'I)
+ ((has-suffix? l "?") 7)
+ (else 9))))
+
+
+;;; Selector retrieval
+
+(define (serve-selector raw-selector remote-ip config)
+ (let* ((selector-list (string-split raw-selector "\t"))
+ (selector (car selector-list))
+ (arguments (cdr selector-list)))
+ (case (infer-selector-type selector)
+ ((1) (serve-directory selector config))
+ ((0) (serve-text-file selector config))
+ ((7) (serve-query selector arguments remote-ip config))
+ (else (serve-binary-file selector config)))))
+
+(define (serve-directory selector config)
+ (let ((file-name (make-pathname (list (config-root-dir config) selector)
+ gopher-index-file-name)))
+ (if (regular-file? file-name)
+ (begin
+ (with-input-from-file file-name
+ (lambda ()
+ (let loop ((c (peek-char)))
+ (if (eof-object? c)
+ 'done
+ (begin
+ (if (eq? c #\,)
+ (begin
+ (read-char)
+ (serve-record (read) selector config)
+ (read-line))
+ (serve-info-records (read-line)))
+ (loop (peek-char)))))))
+ (if (config-display-footer config)
+ (serve-info-records burrower-footer)))
+ (error "Index file not found."))))
+
+(define (serve-text-file selector config)
+ (let ((file-name (make-pathname (config-root-dir config) selector)))
+ (if (regular-file? file-name)
+ (with-input-from-file file-name
+ (lambda ()
+ (for-each
+ (lambda (line)
+ (print line "\r"))
+ (read-lines))))
+ (error "File not found." file-name))))
+
+(define (serve-binary-file selector config)
+ (let ((file-name (make-pathname (config-root-dir config) selector)))
+ (if (regular-file? file-name)
+ (with-input-from-file file-name
+ (lambda ()
+ (let loop ((b (read-byte)))
+ (if (eof-object? b)
+ 'done
+ (begin
+ (write-byte b)
+ (loop (read-byte)))))))
+ (error "File not found." file-name))))
+
+(define (serve-query selector arguments remote-ip config)
+ (let ((file-name (make-pathname (config-root-dir config)
+ (conc (string-chomp selector "?") ".scm"))))
+ (if (and (regular-file? file-name)
+ (= (length arguments) 1))
+ (with-input-from-file file-name
+ (lambda ()
+ (serve-info-records
+ (with-selector-dir
+ selector config
+ (lambda ()
+ (apply (eval (read))
+ (list (car arguments) remote-ip)))))))
+ (error "Invalid query."))))
+
+
+;;; Index rendering
+
+(define (serve-info-records string)
+ (for-each
+ (lambda (line)
+ (print* "i")
+ (for-each (lambda (char)
+ (print* (if (eq? char #\tab)
+ " "
+ char)))
+ (string->list line))
+ (print "\tfake\tfake\t1\r"))
+ (string-split string "\n" #t)))
+
+(define (serve-record record dir-selector config)
+ (match record
+ (('shell command) (serve-shell-command command dir-selector config))
+ (('eval expression) (serve-expression expression dir-selector config))
+ (('url display-string url)
+ (print #\h display-string "\tURL:" url "\tfake\t80\r"))
+ ((type display-string selector host port)
+ (print type display-string "\t" selector "\t" host "\t" port "\r"))
+ ((type display-string selector host)
+ (serve-record (list type display-string selector host 70)
+ dir-selector config))
+ ((type display-string selector)
+ (serve-record (list type display-string
+ (make-pathname dir-selector selector)
+ (config-host config) (config-port config))
+ dir-selector config))
+ ((display-string selector)
+ (serve-record (list (infer-selector-type selector) display-string selector)
+ dir-selector config))
+ ((selector)
+ (serve-record (list (infer-selecto-type selector) selector)
+ dir-selector config))
+ (else (error "Unknown record type."))))
+
+(define (serve-shell-command command dir-selector config)
+ (with-selector-dir
+ dir-selector config
+ (lambda ()
+ (let-values (((in-port out-port id) (process command)))
+ (serve-info-records (string-chomp (read-string #f in-port) "\n"))))))
+
+(define (serve-expression expression dir-selector config)
+ (with-selector-dir
+ dir-selector config
+ (lambda ()
+ (serve-info-records (conc (eval expression))))))
+
+
+;;; Utility methods
+
+(define (with-current-working-directory directory thunk)
+ (let ((old-wd (current-directory))
+ (result 'none))
+ (change-directory directory)
+ (set! result (thunk))
+ (change-directory old-wd)
+ result))
+
+(define (with-selector-dir selector config thunk)
+ (with-current-working-directory
+ (make-pathname (config-root-dir config)
+ (pathname-directory selector)) thunk))
+
+;;; main
+
+(define (print-usage progname)
+ (print "Usage:\n"
+ progname " -h/--help\n"
+ progname " [-n/--no-footer] gopher-root-dir server-hostname [server-port]\n"
+ "\n"
+ "The -n option tells the server to not display a directory footer."))
+
+(define (main)
+ (let* ((progname (car (argv)))
+ (args (cdr (argv)))
+ (config (make-config '() '() 70 #t)))
+
+ (if (or (null? args)
+ (equal? (car args) "-h")
+ (equal? (car args) "--help"))
+ (print-usage progname)
+ (begin
+ (if (or (equal? (car args) "-n")
+ (equal? (car args) "--no-footer"))
+ (begin
+ (config-display-footer-set! config #f)
+ (set! args (cdr args))))
+ (if (or (< (length args) 2)
+ (> (length args) 3))
+ (print-usage progname)
+ (begin
+ (config-root-dir-set! config (car args))
+ (config-host-set! config (cadr args))
+ (if (= (length args) 3)
+ (config-port-set! config (string->number (caddr args))))
+ (run-server config)))))))
+
+(main)
+
+;; (define (test)
+;; (run-server (make-config "gopher-root" "localhost" 70 #t)))
+
+;; (test)
The Lambda Lab / projects / scratchy.git / blobdiff