10 (chicken process-context)
11 srfi-1 srfi-13 matchable)
15 (define gopher-index-file-name "index")
17 (define burrow-version "1.0.0")
21 "--------------------------------------------------\n"
22 "Served by Burrow Gopher Server v" burrow-version "\n"
23 "Powered by Chicken Scheme!"))
28 ;; We don't yet use worker threads here to handle requests,
29 ;; the server just blocks until the first request is finished.
30 ;; While we should fix this, it's actually probably okay, as
31 ;; we genuinely don't expect a huge flood of gopher traffic. :-(
33 (define-record config root-dir host port display-footer)
35 (define (run-server config)
36 (print "Gopher server listening on port " (config-port config) " ...")
37 (let ((listener (tcp-listen (config-port config))))
39 (let-values (((in-port out-port) (tcp-accept listener)))
40 (let* ((line (read-line in-port))
41 (selector (string-trim-both line)))
42 (let-values (((local-ip remote-ip) (tcp-addresses in-port)))
43 (print "Accepted connection from " remote-ip
44 " on " (seconds->string))
47 (with-output-to-port out-port
49 (serve-selector (if (= (string-length selector) 0)
53 (print "... served selector '" selector "'. Closing connection."))
55 (print-error-message o out-port)
56 (print-error-message o)
57 (print "Error while attempting to serve selector " selector ".")))))
58 (close-input-port in-port)
59 (close-output-port out-port))
61 (tcp-close listener)))
64 ;;; Selector type inference
66 (define (has-suffix? selector . suffixes)
69 (if (string-suffix? (car suffixes) selector)
71 (apply has-suffix? selector (cdr suffixes)))))
73 (define (infer-selector-type selector)
74 (let ((l (string-downcase selector)))
76 ((or (= (string-length l) 0) (string-suffix? "/" l)) 1)
77 ((has-suffix? l ".txt" ".org" ".md") 0)
78 ((has-suffix? l ".png" ".jpg" ".gif" ".bmp" ".tif" ".tga") 'I)
79 ((has-suffix? l "?") 7)
83 ;;; Selector retrieval
85 (define (serve-selector raw-selector remote-ip config)
86 (let* ((selector-list (string-split raw-selector "\t"))
87 (selector (car selector-list))
88 (arguments (cdr selector-list)))
89 (case (infer-selector-type selector)
90 ((1) (serve-directory selector config))
91 ((0) (serve-text-file selector config))
92 ((7) (serve-query selector arguments remote-ip config))
93 (else (serve-binary-file selector config)))))
95 (define (serve-directory selector config)
96 (let ((file-name (make-pathname (list (config-root-dir config) selector)
97 gopher-index-file-name)))
98 (if (regular-file? file-name)
100 (with-input-from-file file-name
102 (let loop ((c (peek-char)))
109 (serve-record (read) selector config)
111 (serve-info-records (read-line)))
112 (loop (peek-char)))))))
113 (if (config-display-footer config)
114 (serve-info-records burrow-footer)))
115 (error "Index file not found."))))
117 (define (serve-text-file selector config)
118 (let ((file-name (make-pathname (config-root-dir config) selector)))
119 (if (regular-file? file-name)
120 (with-input-from-file file-name
126 (error "File not found." file-name))))
128 (define (serve-binary-file selector config)
129 (let ((file-name (make-pathname (config-root-dir config) selector)))
130 (if (regular-file? file-name)
131 (with-input-from-file file-name
133 (let loop ((b (read-byte)))
138 (loop (read-byte)))))))
139 (error "File not found." file-name))))
141 (define (serve-query selector arguments remote-ip config)
142 (let ((file-name (make-pathname (config-root-dir config)
143 (conc (string-chomp selector "?") ".scm"))))
144 (if (and (regular-file? file-name)
145 (= (length arguments) 1))
146 (with-input-from-file file-name
148 (serve-info-records (apply (eval (read))
149 (list (car arguments) remote-ip)))))
150 (error "Invalid query."))))
155 (define (serve-info-records string)
159 (for-each (lambda (char)
160 (print* (if (eq? char #\tab)
164 (print "\tfake\tfake\t1\r"))
165 (string-split string "\n" #t)))
167 (define (serve-record record path config)
169 (('shell command) (serve-shell-command command))
170 (('eval expression) (serve-expression expression))
171 (('url display-string url)
172 (print #\h display-string "\tURL:" url "\tfake\t80\r"))
173 ((type display-string selector host port)
174 (print type display-string "\t" selector "\t" host "\t" port "\r"))
175 ((type display-string selector host)
176 (serve-record (list type display-string selector host 70)
178 ((type display-string selector)
179 (serve-record (list type display-string selector
180 (config-host config) (config-port config))
182 ((display-string selector)
183 (serve-record (list (infer-selector-type selector) display-string selector)
186 (serve-record (list (infer-selecto-type selector) selector)
188 (else (error "Unknown record type."))))
190 (define (serve-shell-command command)
191 (let-values (((in-port out-port id) (process command)))
192 (serve-info-records (string-chomp (read-string #f in-port) "\n"))))
194 (define (serve-expression expression)
195 (serve-info-records (conc (eval expression))))
200 (define (with-current-working-directory directory thunk)
201 (let ((old-wd (current-directory)))
202 (change-directory directory)
204 (change-directory old-wd)))
206 (define (with-selector-dir selector thunk)
207 (with-current-working-directory (pathname-directory selector) thunk))
211 (define (print-usage progname)
213 progname " -h/--help\n"
214 progname " [-n/--no-footer] gopher-root-dir server-hostname [server-port]\n"
216 "The -n option tells the server to not display a directory footer."))
219 (let* ((progname (car (argv)))
221 (config (make-config '() '() 70 #t)))
224 (equal? (car args) "-h")
225 (equal? (car args) "--help"))
226 (print-usage progname)
228 (if (or (equal? (car args) "-n")
229 (equal? (car args) "--no-footer"))
231 (config-display-footer-set! config #f)
232 (set! args (cdr args))))
234 (if (or (< (length args) 2)
236 (print-usage progname)
238 (config-root-dir-set! config (car args))
239 (config-host-set! config (cadr args))
240 (if (= (length args) 3)
241 (config-port-set! config (string->number (caddr args))))
242 (run-server config)))))))
247 (run-server (make-config "gopher-root" "localhost" 70 #t)))