139 lines
5.3 KiB
Racket
139 lines
5.3 KiB
Racket
#lang web-server/insta
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(require "model.rkt")
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;; start: request -> doesn't return
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;; Consumes a request and produces a page that displays
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;; all of the web content.
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(define (start request)
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(render-blog-page request))
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;; render-blog-page: request -> doesn't return
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;; Produces an HTML page of the content of the
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;; BLOG.
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(define (render-blog-page request)
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(local [(define (response-generator make-url)
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(response/xexpr
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`(html (head (title "My Blog"))
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(body
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(h1 "My Blog")
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,(render-posts make-url)
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(form ((action
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,(make-url insert-post-handler)))
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(input ((name "title")))
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(input ((name "body")))
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(input ((type "submit"))))))))
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;; parse-post: bindings -> post
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;; Extracts a post out of the bindings.
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(define (parse-post bindings)
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(post (extract-binding/single 'title bindings)
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(extract-binding/single 'body bindings)
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(list)))
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(define (insert-post-handler request)
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(blog-insert-post!
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BLOG (parse-post (request-bindings request)))
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(render-blog-page (redirect/get)))]
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(send/suspend/dispatch response-generator)))
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;; render-post-detail-page: post request -> doesn't return
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;; Consumes a post and produces a detail page of the post.
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;; The user will be able to either insert new comments
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;; or go back to render-blog-page.
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(define (render-post-detail-page a-post request)
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(local [(define (response-generator make-url)
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(response/xexpr
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`(html (head (title "Post Details"))
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(body
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(h1 "Post Details")
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(h2 ,(post-title a-post))
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(p ,(post-body a-post))
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,(render-as-itemized-list
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(post-comments a-post))
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(form ((action
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,(make-url insert-comment-handler)))
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(input ((name "comment")))
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(input ((type "submit"))))
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(a ((href ,(make-url back-handler)))
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"Back to the blog")))))
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(define (parse-comment bindings)
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(extract-binding/single 'comment bindings))
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(define (insert-comment-handler request)
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(render-confirm-add-comment-page
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(parse-comment (request-bindings request))
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a-post
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request))
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(define (back-handler request)
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(render-blog-page request))]
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(send/suspend/dispatch response-generator)))
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;; render-confirm-add-comment-page :
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;; comment post request -> doesn't return
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;; Consumes a comment that we intend to add to a post, as well
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;; as the request. If the user follows through, adds a comment
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;; and goes back to the display page. Otherwise, goes back to
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;; the detail page of the post.
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(define (render-confirm-add-comment-page a-comment a-post request)
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(local [(define (response-generator make-url)
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(response/xexpr
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`(html (head (title "Add a Comment"))
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(body
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(h1 "Add a Comment")
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"The comment: " (div (p ,a-comment))
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"will be added to "
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(div ,(post-title a-post))
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(p (a ((href ,(make-url yes-handler)))
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"Yes, add the comment."))
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(p (a ((href ,(make-url cancel-handler)))
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"No, I changed my mind!"))))))
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(define (yes-handler request)
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(post-insert-comment! a-post a-comment)
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(render-post-detail-page a-post (redirect/get)))
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(define (cancel-handler request)
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(render-post-detail-page a-post request))]
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(send/suspend/dispatch response-generator)))
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;; render-post: post (handler -> string) -> xexpr
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;; Consumes a post, produces an xexpr fragment of the post.
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;; The fragment contains a link to show a detailed view of the post.
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(define (render-post a-post make-url)
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(local [(define (view-post-handler request)
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(render-post-detail-page a-post request))]
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`(div ((class "post"))
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(a ((href ,(make-url view-post-handler)))
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,(post-title a-post))
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(p ,(post-body a-post))
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(div ,(number->string (length (post-comments a-post)))
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" comment(s)"))))
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;; render-posts: (handler -> string) -> xexpr
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;; Consumes a make-url, produces an xexpr fragment
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;; of all its posts.
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(define (render-posts make-url)
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(local [(define (render-post/make-url a-post)
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(render-post a-post make-url))]
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`(div ((class "posts"))
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,@(map render-post/make-url (blog-posts BLOG)))))
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;; render-as-itemized-list: (listof xexpr) -> xexpr
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;; Consumes a list of items, and produces a rendering as
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;; an unorderered list.
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(define (render-as-itemized-list fragments)
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`(ul ,@(map render-as-item fragments)))
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;; render-as-item: xexpr -> xexpr
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;; Consumes an xexpr, and produces a rendering
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;; as a list item.
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(define (render-as-item a-fragment)
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`(li ,a-fragment))
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