4chan.rkt

#lang racket
(require json)
(require net/http-client)

(define (4chan-data board x)
  (let*-values 
      ([(status headers res)
        (http-sendrecv "a.4cdn.org"
                       (string-append "/" board "/" x ".json"))]
       [(json) (read-string 1048576 res)]
       [(page) (string->jsexpr json)])
    page))

(define (4chan-data-page board n)
  (4chan-data board (number->string n 10)))

(define (4chan-data-catalog board)
  (4chan-data board "catalog"))
  
(define (4chan-thread-is-lisp-general? thread)
    (and (hash-has-key? thread 'sub)
         (regexp-match "Lisp General" (hash-ref thread 'sub))))

;; Usage
;; (define catalog (4chan-data-catalog "g"))
;; (filter 4chan-thread-is-lisp-general? (flatten (map (lambda (page) (hash-ref page 'threads)) catalog)))