141 lines
5.0 KiB
Scheme
141 lines
5.0 KiB
Scheme
;;; Path handler for uploading Scheme code to the SU web server -*- Scheme -*-
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;;; This file is part of the Scheme Untergrund Networking package.
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;;; Copyright (c) 1995 by Olin Shivers.
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;;; For copyright information, see the file COPYING which comes with
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;;; the distribution.
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;;; This is really just an handler example demonstrating how to upload code
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;;; into the server.
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;;; Besides, this handler has always been broken because it makes use
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;;; of the concept of http-reader-writer-body which is broken
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;;; itself. See response.scm.
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;;; (do/timeout secs thunk)
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;;; Run THUNK, and gun it down if it hasn't finished in SECS seconds.
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;;; Returns nothing useful, and THUNK gets executed in a subprocess,
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;;; so its side-effects are invisible, as well. This is a clever kludge --
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;;; it uses three subprocesses -- but I don't have interrupts, so I'm hosed.
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(define (do/timeout* secs thunk)
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(run (begin (let ((timer (fork (lambda () (sleep secs))))
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(worker (fork thunk)))
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(receive (process status) (wait-any)
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(ignore-errors
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(lambda ()
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(signal-process (proc:pid (if (eq? worker process)
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timer
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worker))
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signal/kill))))))))
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(define-syntax do/timeout
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(syntax-rules ()
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((do/timeout secs body ...) (do/timeout* secs (lambda () body ...)))))
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;;; The request handler for seval ops.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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(define (seval-handler path req)
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(let ((request-method (request-method req)))
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(cond
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((string=? request-method "POST") ; Could do others also.
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(seval path req))
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((or (string=? request-method "HEAD")
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(string=? request-method "GET"))
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(make-error-response (status-code method-not-allowed) req
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"POST"))
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(else
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(make-error-response (status-code not-implemented) req)))))
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(define (seval path req)
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(let ((body-length (get-body-length-from-content-length req))) ;;make sure we have a valid Content-length header in request
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(make-response
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(status-code ok)
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#f
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(time)
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"text/html"
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'()
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(make-reader-writer-body ;; see response.scm for an explanation why the concept of http-reader-writer-body doesn't work
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(lambda (iport oport options)
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(with-fatal-error-handler
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(lambda (c decline)
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;; no matter what kind of error (might be a server internal error), we emit this webpage:
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(emit-prolog oport)
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(with-tag oport html (xmlnsdecl-attr)
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(newline oport)
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(with-tag oport head ()
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(newline oport)
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(emit-title oport "No Program")
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(newline oport))
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(newline oport)
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(with-tag oport body ()
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(newline oport)
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(emit-header oport 1 "No Program")
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(newline oport)
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(with-tag oport p ()
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(display
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"No program was found in the body of the request.
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The request's body must be form-url encoded and contain a \"program=<sexp>\" pair."
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oport)
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(newline oport))
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(newline oport))
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(newline oport)))
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(let ((sexp (read-request-sexp body-length iport)))
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(http-syslog (syslog-level debug) "read sexp: ~a" sexp)
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(emit-prolog oport)
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(with-tag oport html (xmlnsdecl-attr)
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(newline oport)
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(with-tag oport head ()
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(newline oport)
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(emit-title oport "Scheme program output")
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(newline oport))
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(newline oport)
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(with-tag oport body ()
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(newline oport)
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(do/timeout
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10
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(receive vals
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;; Do the computation.
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(begin (emit-header oport 1 "Output from execution")
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(newline oport)
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(with-tag oport pre ()
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(newline oport)
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(force-output oport); In case we're gunned down.
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(with-current-output-port oport
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(eval-safely sexp))))
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;; Pretty-print the returned value(s).;; hier noch mal newline rausschreiben?
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(emit-header oport 1 "Return value(s)")
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(with-tag oport pre ()
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(for-each (lambda (val) (p val oport))
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vals)))))))))))))
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;;; Read an HTTP request entity body from stdin. The Content-length:
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;;; entity-header field of request REQ tells how many bytes this entity
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;;; is.
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;;; We assume, that the entity is "form-url encoded" data (see
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;;; parse-forms.scm for a description of this encoding). This
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;;; assumption is rather strange - it may safely be made only if
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;;; there's a "Content-type: application/x-www-form-urlencoded" header.
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;;; Pull out the program=<stuff> string, extract <stuff>,
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;;; parse that into an s-expression, and return it.
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(define (read-request-sexp bytes iport)
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(let*
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((body (read-string bytes iport)) ;;read in bytes chars
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(parsed-html-form-query (parse-html-form-query body)) ;; and parse them up.
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(program (cond ((assoc "program" parsed-html-form-query) => cdr)
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(else (error "No program in entity body.")))))
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(http-syslog (syslog-level debug)
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"Seval sexp: ~s" program)
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(read (make-string-input-port program)))) ;; return first sexp, discard others
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