13 (chicken process-context)
14 srfi-1 srfi-13 matchable)
17 ;; (use srfi-1 srfi-13 tcp posix matchable)
21 (define gopher-index-filename "index")
23 (define burrower-version "1.0.0")
25 (define burrower-footer
27 "--------------------------------------------------\n"
28 "This gopher hole was dug using Burrower v" burrower-version ".\n"
29 "Powered by Chicken Scheme!"))
33 ;; We don't yet use worker threads here to handle requests,
34 ;; the server just blocks until the first request is finished.
35 ;; While we should fix this, it's actually probably okay, as
36 ;; we genuinely don't expect a huge flood of gopher traffic. :-(
38 (define-record config root-dir host port display-footer)
40 (define (run-server config)
41 (set-buffering-mode! (current-output-port) #:line)
42 (print "Gopher server listening on port " (config-port config) " ...")
43 (let ((listener (tcp-listen (config-port config))))
45 (let-values (((in-port out-port) (tcp-accept listener)))
46 (let* ((line (read-line in-port))
47 (selector (string-trim-both line)))
48 (let-values (((local-ip remote-ip) (tcp-addresses in-port)))
49 (print "Accepted connection from " remote-ip
50 " on " (seconds->string))
53 (with-output-to-port out-port
55 (serve-selector (if (= (string-length selector) 0)
59 (print "... served selector '" selector "'. Closing connection."))
61 (print-error-message o out-port)
62 (print-error-message o)
63 (print "Error while attempting to serve selector " selector ".")))))
64 (close-input-port in-port)
65 (close-output-port out-port))
67 (tcp-close listener)))
70 ;;; Selector type inference
72 (define (true-for-one? predicate values)
75 (if (predicate (car values))
77 (true-for-one? predicate (cdr values)))))
79 (define (has-suffix? selector . suffixes)
80 (true-for-one? (lambda (suffix)
81 (string-suffix? suffix selector))
84 (define (has-prefix? selector . prefixes)
85 (true-for-one? (lambda (prefix)
86 (string-prefix? prefix selector))
89 (define (infer-selector-type selector)
90 (let ((l (string-downcase selector)))
92 ((or (= (string-length l) 0)
93 (string-suffix? "/" l)
94 (string-contains l ":")) 1)
95 ((has-suffix? l ".txt" ".org" ".md") 0)
96 ((has-suffix? l ".png" ".jpg" ".gif" ".bmp" ".tif" ".tga") 'I)
97 ((has-suffix? l "?" "%3f") 7)
98 ((has-prefix? l "url:" "/url:") 'h)
102 ;;; Selector retrieval
104 (define (serve-selector raw-selector config)
105 (let* ((selector-list (string-split raw-selector "\t"))
106 (selector (car selector-list))
107 (arguments (cdr selector-list)))
108 (case (infer-selector-type selector)
109 ((1) (if (string-contains selector ":")
110 (let ((l (string-split selector ":")))
111 (serve-directory-script (car l) (cdr l)
113 (serve-directory-file selector config)))
114 ((7) (let ((l (string-split selector "?")))
115 (serve-directory-script (car l) arguments config)))
116 ((0) (serve-text-file selector config))
117 ((h) (serve-url selector config))
118 (else (serve-binary-file selector config)))))
120 (define (legal-filename? filename config)
121 (and (string-prefix? (config-root-dir config)
122 (normalize-pathname filename))
123 (file-exists? filename)
124 (not (directory-exists? filename))
125 (file-readable? filename)))
127 (define (legal-script-filename? filename config)
128 (and (legal-filename? filename config)
129 (string-suffix? ".scm" filename)
130 (file-executable? filename)))
132 (define (serve-directory-script selector arguments config)
133 (let ((filename (make-pathname (config-root-dir config) selector)))
134 (if (legal-script-filename? filename config)
135 (let ((sexp (with-input-from-file filename read)))
136 (serve-records (with-selector-dir selector config
138 (apply (eval sexp) arguments)))
141 (error "No legal index script not found." filename))))
143 (define (serve-directory-file selector config)
144 (let ((filename (make-pathname (list (config-root-dir config) selector)
145 gopher-index-filename)))
146 (if (legal-filename? filename config)
148 (with-input-from-file filename
150 (let loop ((c (peek-char)))
157 (serve-record (read) selector config)
159 (serve-info-records (read-line)))
160 (loop (peek-char)))))))
161 (if (config-display-footer config)
162 (serve-info-records burrower-footer))
164 (error "No legal index file not found."))))
166 (define (serve-text-file selector config)
167 (let ((filename (make-pathname (config-root-dir config) selector)))
168 (if (legal-filename? filename config)
170 (with-input-from-file filename
177 (error "File not found." filename))))
179 (define (serve-binary-file selector config)
180 (let ((filename (make-pathname (config-root-dir config) selector)))
181 (if (legal-filename? filename config)
182 (with-input-from-file filename
184 (let loop ((b (read-byte)))
189 (loop (read-byte)))))))
190 (error "File not found." filename))))
192 (define (serve-url selector config)
193 (let ((url (substring selector 4)))
195 "<html><head><title>Redirection</title>"
196 "<meta http-equiv=\"refresh\" content=\"10; URL='" url "'\" />"
198 "<p>If you are seeing this page, your gopher browser does not "
199 "properly support URL directory entries or cannot follow such "
201 "<p>If you are viewing this page using a web browser, you should "
202 "be redirected shortly. Otherwise, you can manually open the "
203 "the follwing url:\n"
205 "<a href=\"" url "\">" url "</a>\n"
211 (define (serve-records records dir-selector config)
214 (serve-record record dir-selector config))
217 (define (serve-info-records string)
221 (for-each (lambda (char)
222 (print* (if (eq? char #\tab)
226 (print "\tfake\tfake\t1\r"))
227 (string-split string "\n" #t)))
229 (define (serve-record record dir-selector config)
231 ((? string?) (serve-info-records record))
232 (('shell command) (serve-shell-command command dir-selector config))
233 (('eval expression) (serve-expression expression dir-selector config))
234 (('url display-string url)
235 (print #\h display-string "\tURL:" url
236 "\t" (config-host config)
237 "\t" (config-port config) "\r"))
238 ((type display-string selector host port)
239 (print type display-string "\t" selector "\t" host "\t" port "\r"))
240 ((type display-string selector host)
241 (serve-record (list type display-string selector host 70)
242 dir-selector config))
243 ((type display-string selector)
244 (serve-record (list type display-string
245 (make-pathname dir-selector selector)
246 (config-host config) (config-port config))
247 dir-selector config))
248 ((display-string selector)
249 (serve-record (list (infer-selector-type selector) display-string selector)
250 dir-selector config))
252 (serve-record (list (infer-selector-type selector) selector)
253 dir-selector config))
254 (else (error "Unknown record type."))))
256 (define (serve-shell-command command dir-selector config)
260 (let-values (((in-port out-port id) (process command)))
261 (let ((string (read-string #f in-port)))
262 (if (and (not (eof-object? string))
263 (> (string-length string) 0))
264 (serve-info-records (string-chomp string "\n"))))))))
266 (define (serve-expression expression dir-selector config)
270 (serve-records (eval expression) dir-selector config))))
275 (define (with-current-working-directory directory thunk)
276 (let ((old-wd (current-directory))
280 (change-directory directory)
281 (set! result (thunk))
282 (change-directory old-wd)
285 (change-directory old-wd)
288 (define (with-selector-dir selector config thunk)
289 (with-current-working-directory
290 (make-pathname (config-root-dir config)
291 (pathname-directory selector)) thunk))
296 (define (print-usage progname)
298 progname " -h/--help\n"
299 progname " [-n/--no-footer] gopher-root-dir server-hostname [server-port]\n"
301 "The -n option tells the server to not display a directory footer."))
304 (let* ((progname (car (argv)))
306 (config (make-config '() '() 70 #t)))
309 (equal? (car args) "-h")
310 (equal? (car args) "--help"))
311 (print-usage progname)
313 (if (or (equal? (car args) "-n")
314 (equal? (car args) "--no-footer"))
316 (config-display-footer-set! config #f)
317 (set! args (cdr args))))
318 (if (or (< (length args) 2)
320 (print-usage progname)
322 (config-root-dir-set! config (car args))
323 (config-host-set! config (cadr args))
324 (if (= (length args) 3)
325 (config-port-set! config (string->number (caddr args))))
326 (run-server config)))))))
331 ;; (run-server (make-config "gopher-root" "localhost" 70 #t)))