146 lines
4.0 KiB
Racket
146 lines
4.0 KiB
Racket
#lang racket
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(require (prefix-in net: "net.rkt")
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(prefix-in gmi: "gmi.rkt"))
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(require net/url-string)
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;; global state variable which will be an input port containing the
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;; rendered out gemtext document as it shall be shown to the user
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(define document-buffer null)
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;; global state which will be the document structure, before rendering
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(define document null)
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;; global state for the url of the currently visited document
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(define current-url null)
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(define temporary-failures
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'((40 . "temporary failure")
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(41 . "server unavailable")
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(42 . "CGI error")
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(43 . "proxy error")
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(44 . "slow down")))
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(define permanent-failures
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'((50 . "permanent failure")
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(51 . "not found")
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(52 . "gone")
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(53 . "proxy request refused")
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(59 . "bad request")))
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(define (get url-str)
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(define (iter url-str depth)
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(let-values ([(status header c-in) (net:request url-str)])
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;; TODO there are bunch of other status codes to deal with for
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;; compliance
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(cond
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;; clients MUST reject status codes outside of the 10-69 range
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[(or (< status 10)
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(> status 69))
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(displayln "WARNING: server returned invalid status code")]
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;; 10-19 INPUT REQUIRED
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[(and (>= status 10)
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(<= status 19))
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(display "input requested > ")
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(get (string-append url-str "?" (read-line)))]
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;; 20-29 SUCCESS
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[(and (>= status 20)
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(<= status 29))
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(let-values ([(doc) (gmi:parse (port->lines c-in))]
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[(db-in db-out) (make-pipe #f)])
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(set! document doc)
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(set! document-buffer db-in)
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(parameterize ([current-output-port db-out])
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(gmi:render doc))
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(set! current-url url-str)
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(let ([remaining (pipe-content-length db-in)])
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(printf "document retrieved. ~a bytes\n" remaining))
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(next-cmd))]
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;; 30-39 REDIRECT
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[(and (>= status 30)
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(<= status 39))
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(if (> depth 5)
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(displayln "WARNING: maximum redirection depth exceeded")
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(iter header (sub1 depth)))]
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;; 40-49 TEMPORARY FAILURE
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[(and (>= status 40)
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(<= status 49))
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(printf "status ~a: ~a\n" status
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(dict-ref temporary-failures status "temporary failure"))]
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;; 50-59 PERMANENT FAILURE
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[(and (>= status 50)
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(<= status 59))
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(printf "status ~a: ~a\n" status
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(dict-ref permanent-failures status "permanent failure"))]
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;; 60-69 CERTIFICATE REQUIRED
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[(and (>= status 60)
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(<= status 69))
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(displayln "certificate handling not yet implemented")])))
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(iter url-str 5))
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(define (go-cmd url)
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(if (non-empty-string? url)
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(let ()
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(when (not (string-contains? url "://"))
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(set! url (string-append "gemini://" url)))
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(get url))
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(displayln "go where?")))
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(define (next-cmd)
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(define (iter depth)
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(when (and (> depth 0)
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(> (pipe-content-length document-buffer) 0))
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(let ()
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(displayln (read-line document-buffer))
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(iter (sub1 depth)))))
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(iter 10)
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(newline)
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(let ([remaining (pipe-content-length document-buffer)])
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(printf "~a bytes remaining\n" remaining)))
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(define (visit-cmd line)
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(define url (gmi:match-link document (string->number line)))
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(set! url
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(url->string (combine-url/relative (string->url current-url)
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url)))
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(get url))
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(define (repl)
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(display "G-300 > ")
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(let ([matches (regexp-match #px"(\\w+)\\s*(.*)" (read-line))])
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(cond
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;; next command. also default
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[(or (not matches)
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(string=? (cadr matches) "next")
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(string=? (cadr matches) "n"))
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(next-cmd)]
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;; go command
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[(or (string=? (cadr matches) "go")
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(string=? (cadr matches) "g"))
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(go-cmd (caddr matches))]
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;; visit link command
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[(andmap char-numeric? (string->list (cadr matches)))
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(visit-cmd (cadr matches))]))
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(repl))
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