132 lines
4.5 KiB
Racket
132 lines
4.5 KiB
Racket
#lang racket
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(require web-server/servlet
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web-server/servlet-env)
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(require "challenge.rkt")
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(require "either.rkt")
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(require "challenges.rkt")
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(require "validate.rkt")
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(require racket/format)
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(define intro (file->string "intro.txt"))
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; start: request -> response
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; Consumes a request and produces a page that displays all of the
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; web content.
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(define (start request)
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(define updated-challenges
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(cond ((can-parse-attempt? (request-bindings request))
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(process-attempt (request-bindings request)))
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(else
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challenges)))
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(render-page updated-challenges))
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; Produces true if bindings contains values for 'id and 'code
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(define (can-parse-attempt? bindings)
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(and (exists-binding? 'id bindings)
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(exists-binding? 'code bindings)))
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; The main piece of code for processing a request
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; Takes care of all necesarry error handling and updates a challenge based on the results
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(define (process-attempt bindings)
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(define input-id (extract-binding/single 'id bindings))
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(define result
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(do
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(<- id (parse-id input-id))
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(let code (extract-binding/single 'code bindings))
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(<- challenge (get-challenge id))
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(let allowed (challenge-allowed challenge))
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(<- validated-code (validate code allowed))
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(run challenge validated-code)))
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(reduce (add-response input-id 'fail) (add-response input-id 'success) result))
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; Parse the id of the request
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(define (parse-id id)
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(define num (string->number id))
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(if num
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(right num)
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(left "Error parsing challenge id, not a valid number")))
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; Adds a result to a single challenge (1 arg curried)
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(define (add-response id status)
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(define id-num (string->number id))
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(lambda (err)
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(map (lambda (ch)
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(if (equal? id-num (challenge-id ch))
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(add-status status err ch)
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ch))
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challenges)))
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; Tries to obtain a certain challenge
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(define (get-challenge id)
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(if (or (< id 0) (>= id (length challenges)))
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(left "Bad challenge id given, stop hacking my platform >:(")
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(right (list-ref challenges id))))
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; Renders the entire page
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(define (render-page challenges)
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(response/xexpr
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`(html (head
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(title "Scheme Challenges!")
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(link ((rel "stylesheet") (href "style.css")))
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(link ((rel "shortcut icon") (href "favicon.ico") (type "image/x-icon"))))
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(body
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,(render-intro)
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,(render-challenges challenges)
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(div ((style "display: none;"))
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(a ((href "sicp.jpg")) "Hidden url :o "))))))
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; Renders the explanations etc
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(define (render-intro)
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`(div ((class "intro"))
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(h2 "Scheme Programming Challenges")
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(p ,intro)))
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; Renders all challenges
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(define (render-challenges challenges)
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`(div ((class "challenges"))
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,@(map render-challenge challenges)))
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; Renders a single challenge
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(define (render-challenge challenge)
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(define status (challenge-status challenge))
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(define err? (eq? status 'fail))
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(define succ? (eq? status 'success))
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`(div ((class "challenge"))
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(h3 ,(string-append "Challenge " (number->string(challenge-id challenge))))
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(p ,(challenge-description challenge))
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(div ((class "input-str"))
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"Allowed procedures, special-forms and variable names:")
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(div ((class "output"))
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,(apply ~a (challenge-allowed challenge) #:separator " | "))
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(div ((class "input-str"))
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"Given input:")
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(div ((class "output"))
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,(apply ~a (challenge-input challenge) #:separator " | "))
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(div ((class "output-str"))
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"Expected output:")
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(div ((class "output"))
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,(apply ~a (challenge-output challenge) #:separator " | "))
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(form
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(input ((name "id") (type "hidden") (value ,(number->string (challenge-id challenge)))))
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(textarea ((name "code")))
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(button ((type "submit")) "Get flag!"))
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(div ((class "error") (style ,(if err? "" "display: none;")))
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,(if (pair? (challenge-err challenge))
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(apply ~a (challenge-err challenge) #:separator " | ")
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(~a (challenge-err challenge))))
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(div ((class "flag") (style ,(if succ? "" "display: none;")))
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,(if succ?
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(challenge-flag challenge)
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"")))) ;TODO input is cleared after submission
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; #:listen-ip #f
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; #:command-line? #t
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(serve/servlet start
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#:servlet-path "/"
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#:listen-ip #f
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#:command-line? #t
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#:extra-files-paths (list (build-path "assets/")))
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