72 lines
2.1 KiB
Racket
72 lines
2.1 KiB
Racket
#lang racket
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(provide get)
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(require openssl)
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(require net/url)
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;; sends a request to a gemini server, and returns the status, header,
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;; and the input port for the rest of the body.
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;; this procedure will fail if the response is malformed, however, it
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;; is not up to it to validate the contents of the response.
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(define (send-request url-str)
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(define url (string->url url-str))
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(define-values (c-in c-out)
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(ssl-connect (url-host url)
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(or (url-port url) 1965)))
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(write-string url-str c-out)
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(write-string "\r\n" c-out)
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(define-values (status header)
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(read-response c-in))
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(values status header c-in))
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(define (read-response (c-in (current-input-port)))
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(define maxlen 1027)
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(let ([header (peek-string maxlen 0 c-in)])
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(if (not (string-contains? header "\r\n"))
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(error "header exceeds maximum length")
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(let ([header (read-line c-in 'return-linefeed)])
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(define-values (status meta)
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(let ([status-meta (string-split header " ")])
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(values (car status-meta)
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(string-join (cdr status-meta)))))
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(cond
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[(> (string-length status) 2)
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(error "status code exceeds maximum length")]
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[(andmap (compose not char-numeric?) (string->list status))
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(error "status code is not numeric")]
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[else
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(values (string->number status) meta)])))))
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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) (send-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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(error "server returned invalid status code")]
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;; 30-39 redirection
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[(and (>= status 30)
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(<= status 39))
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(if (> depth 5)
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(error "maximum redirection depth exceeded")
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(iter header (sub1 depth)))]
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[else
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(values status header c-in)])))
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(iter url-str 5))
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