Minimum-Feed-Reader, example for cl-feed-parser (https://github.com/tkych/cl-feed-parser)

minimum-feed-reader.lisp

;;;; Last modified : 2013-08-17 21:01:33 tkych

;; Example for cl-feed-parser (https://github.com/tkych/cl-feed-parser)


;; Usage:
;; ------
;; * (defparameter f "http://www.whitehouse.gov/feed/press")
;; * (show-entry-titles f)
;; * (read-nth-entry 2 f)


;;====================================================================
;; Minimum-Feed-Reader
;;====================================================================

(in-package :cl-user)

(eval-when (:compile-toplevel :load-toplevel :execute)
  (ql:quickload :cl-feed-parser))

(defpackage #:mini-feed-reader
  (:use :cl)
  (:export #:show-entry-titles
           #:read-nth-entry))

(in-package #:mini-feed-reader)


;;--------------------------------------------------------------------
;; Note:
;; If you make a real feed reader, you should use :etag, :modified or
;; :request-headers for caching.

(let ((cache (make-hash-table :test #'equal)))
  (defun parse (feed-spec)
    (or (gethash feed-spec cache nil)
        (setf (gethash feed-spec cache)
              (feed-parser:parse-feed feed-spec)))))

(defun show-entry-titles (feed-spec)
  (let ((f (parse feed-spec)))
    (loop
       :for i :from 0
       :for title := (feed-parser:ref f :entries i :title)
       :until (null title)
       :do (format t "~&[~D]: ~A" i title))))

(defun read-nth-entry (nth feed-spec)
  (princ (or (feed-parser:ref (parse feed-spec)
                              :entries nth :description)
             (feed-parser:ref (parse feed-spec)
                              :entries nth :summary)))
  nil)


;;====================================================================