116 lines
2.8 KiB
Scheme
116 lines
2.8 KiB
Scheme
(define-structure servlet servlet-interface
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(open httpd-requests ; REQUEST-URL
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httpd-responses ; MAKE-RESPONSE
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parse-html-forms ; PARSE-HTML-FORM-QUERY
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url ; HTTP-URL-SEARCH
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srfi-1 ; FILTER
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servlet-handler/servlet ; SEND/SUSPEND, SEND/FINISH
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scheme-with-scsh)
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(begin
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(define (extract-bindings key bindings)
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(map cdr
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(filter (lambda (binding)
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(equal? (car binding) key))
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bindings)))
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(define (extract-single-binding key bindings)
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(let ((bindings (extract-bindings key bindings)))
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(if (null? bindings)
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(error "no binding")
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(car bindings))))
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(define (make-get-number-page input-text title)
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(lambda (new-url)
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(let ((HTML-page (format #f "
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<HTML>~a
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<BODY>~a
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<P>
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<FORM method=\"GET\" action=\"~a\">
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~a
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<INPUT type=\"text\" name=\"number\">
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<INPUT type=\"submit\">
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</FORM>
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</P>
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<HR>
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<P>
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<A href=\"/\">Return to main menu.</A><BR>
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<A href=\"add-html.scm\">Start new calculation.</A>
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</P>
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</BODY>
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</HTML>"
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(if title
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(format #f "<TITLE>~a</TITLE>" title)
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"")
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(if title
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(format #f "<H2>~a</H2>" title))
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new-url
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input-text
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)))
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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-writer-body
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(lambda (out options)
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(format out HTML-page))
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)))))
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(define (make-result-page new-url)
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(let ((HTML-page (format #f "
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<HTML>
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<TITLE>Result</TITLE>
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<BODY>
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<H1>Result</H1>
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<P>
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~a
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<P>
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<HR>
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<A href=\"add-html.scm\">New calculation (new session)</A><BR>
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<A href=\"javascript:history.back(2)\">New calculation (same session)</A><BR>
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<A href=~s>Close this session</A>
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</BODY>
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</HTML>"
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(number->string (+ (get-number1) (get-number2)))
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new-url)))
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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-writer-body
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(lambda (out options)
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(format out HTML-page)))
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)))
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(define (get-number input-text . maybe-title)
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(let* ((title (if (pair? maybe-title) (car maybe-title) #f))
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(result (send/suspend (make-get-number-page input-text title)))
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(bindings (parse-html-form-query
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(http-url-search (request-url result))))
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(number (string->number
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(extract-single-binding "number" bindings))))
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(if number
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number
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(get-number input-text "Please enter a valid number"))))
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(define (get-number1)
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(get-number "First number:" "Calculation - Step one"))
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(define (get-number2)
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(get-number "Second number:" "Calculation - Step two"))
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(define (main req)
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(send/suspend make-result-page)
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;; This finishes the session and does a redirect to the root
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;; page.
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(send/finish
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(make-error-response (status-code moved-temp) req
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"/" "/")))
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))
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