A Racket Blog

index.rkt

#lang web-server/insta

; A blog is a (listof post)
; and a post is a (post title body)
(struct post (title body))

; BLOG: blog
; The static blog.
(define BLOG
  (list (post "Second Post" "This is anther post")
        (post "First Post" "This is my first post")))

; start: request -> response
; Consumes a request, and produces a page that displays all of the
; web content.
(define (start request)
  (local [(define a-blog
            (cond [(can-parse-post? (request-bindings request))
                   (cons (parse-post (request-bindings request))
                         BLOG)]
                  [else
                   BLOG]))]
  (render-blog-page a-blog request)))
  
; can-parse-post?: bindings -> boolean
; Produces true if bindings  contains values for 'title and 'body.
(define (can-parse-post? bindings)
  (and (exists-binding? 'title bindings)
       (exists-binding? 'body bindings)))

; parse-post: bindings -> post
; Consumes a bindings, and produces a post out of the bindings.
(define (parse-post bindings)
  (post (extract-binding/single 'title bindings)
        (extract-binding/single 'body bindings)))


; render-blog-page: blog request -> response
; Consumes a blog and a request, and produces an HTML page
; of the content of the blog.
(define (render-blog-page a-blog request)
  (response/xexpr
   '(html (head (titile "My Blog"))
          (body 
           (h1 "My Blog")
                ,(render-post a-blog)
                (form
                 (input ((name "title")))
                 (input ((name "body")))
                 (input ((type "submit"))))))))

; render-post: post -> xexpr
; Consumes a post, produces an xexpr fragment of the post.
(define (render-post a-post)
  '(div ((class "post"))
        ,(post-title a-post)
        (p, (post-body a-post))))

; render-posts: blog -> xexpr
; Consumes a blog, produces an xexpr fragment
; of all its posts.
(define (render-posts a-blog)
  '(div ((class "posts"))
        ,@(map render-post a-blog)))