98 lines
3.0 KiB
Plaintext
98 lines
3.0 KiB
Plaintext
#lang scheme
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;; There's only one change. It's in `accept-and-handle',
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;; and it's marked with "<<<".
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(require xml net/url)
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(define (serve port-no)
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(define main-cust (make-custodian))
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(parameterize ([current-custodian main-cust])
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(define listener (tcp-listen port-no 5 #t))
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(define (loop)
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(accept-and-handle listener)
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(loop))
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(thread loop))
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(lambda ()
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(custodian-shutdown-all main-cust)))
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(define (accept-and-handle listener)
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(define cust (make-custodian))
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(custodian-limit-memory cust (* 50 1024 1024)) ;; <<< new line
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(parameterize ([current-custodian cust])
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(define-values (in out) (tcp-accept listener))
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(thread (lambda ()
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(handle in out)
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(close-input-port in)
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(close-output-port out))))
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;; Watcher thread:
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(thread (lambda ()
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(sleep 10)
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(custodian-shutdown-all cust))))
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(define (handle in out)
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(define req
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;; Match the first line to extract the request:
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(regexp-match #rx"^GET (.+) HTTP/[0-9]+\\.[0-9]+"
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(read-line in)))
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(when req
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;; Discard the rest of the header (up to blank line):
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(regexp-match #rx"(\r\n|^)\r\n" in)
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;; Dispatch:
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(let ([xexpr (dispatch (list-ref req 1))])
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;; Send reply:
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(display "HTTP/1.0 200 Okay\r\n" out)
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(display "Server: k\r\nContent-Type: text/html\r\n\r\n" out)
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(display (xexpr->string xexpr) out))))
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(define (dispatch str-path)
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;; Parse the request as a URL:
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(define url (string->url str-path))
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;; Extract the path part:
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(define path (map path/param-path (url-path url)))
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;; Find a handler based on the path's first element:
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(define h (hash-ref dispatch-table (car path) #f))
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(if h
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;; Call a handler:
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(h (url-query url))
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;; No handler found:
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`(html (head (title "Error"))
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(body
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(font ((color "red"))
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"Unknown page: "
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,str-path)))))
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(define dispatch-table (make-hash))
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(hash-set! dispatch-table "hello"
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(lambda (query)
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`(html (body "Hello, World!"))))
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;; ----------------------------------------
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(define (build-request-page label next-url hidden)
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`(html
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(head (title "Enter a Number to Add"))
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(body ([bgcolor "white"])
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(form ([action ,next-url] [method "get"])
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,label
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(input ([type "text"] [name "number"]
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[value ""]))
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(input ([type "hidden"] [name "hidden"]
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[value ,hidden]))
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(input ([type "submit"] [name "enter"]
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[value "Enter"]))))))
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(define (many query)
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;; Create a page containing the form:
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(build-request-page "Number of greetings:" "/reply" ""))
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(define (reply query)
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;; Extract and use the form results:
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(define n (string->number (cdr (assq 'number query))))
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`(html (body ,@(for/list ([i (in-range n)])
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" hello"))))
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(hash-set! dispatch-table "many" many)
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(hash-set! dispatch-table "reply" reply)
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