twitter-filter.lisp

   1 ;; Twitter Filter A simple filter for custom twitter lists
   2 ;; Copyright (C) 2012 Panagiotis Koutsourakis
   3
   4 ;; This program is free software: you can redistribute it and/or modify
   5 ;; it under the terms of the GNU General Public License as published by
   6 ;; the Free Software Foundation, either version 3 of the License, or
   7 ;; (at your option) any later version.
   8
   9 ;; This program is distributed in the hope that it will be useful,
  10 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 ;; GNU General Public License for more details.
  13
  14 ;; You should have received a copy of the GNU General Public License
  15 ;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 (ql:quickload "drakma")
  18 (ql:quickload "cl-json")
  19
  20 (defpackage :twitter-filter
  21   (:use :cl :drakma :json)
  22   (:export :parse-query))
  23
  24 (in-package :twitter-filter)
  25
  26 (defparameter *search-url* "http://search.twitter.com/search.json?q=")
  27
  28 (defun convert-response-to-string (resp)
  29   "The server response is an array of integers. This function converts
  30 it to a string."
  31   (coerce (mapcar #'code-char (coerce resp 'list)) 'string))
  32
  33 (defun percent-encode (str)
  34   "Make the string percent encoded in order to be compatible with
  35 URLs."
  36   (labels ((percent-encode-char-list (char-list)
  37              (let ((curr (car char-list))
  38                    (rest (cdr char-list)))
  39                (cond
  40                  ((null rest) (cons curr nil))
  41                  ((eq curr #\#)
  42                       (append '(#\% #\2 #\3) (percent-encode-char-list rest)))
  43 ;                 ((eq curr ))
  44                  (t (cons curr (percent-encode-char-list rest)))))))
  45     (coerce (percent-encode-char-list (coerce str 'list)) 'string)))
  46
  47 (defun make-query (search-term)
  48   "Make the actual search query to the twitter API."
  49   (http-request (concatenate 'string *search-url* (percent-encode search-term))))
  50
  51
  52 (defun parse-query (search-term)
  53   "Convert the response to Lisp objects using cl-json library."
  54   (with-input-from-string
  55       (s (convert-response-to-string (make-query search-term)))
  56     (decode-json s)))
  57
  58 (defparameter *white-list-mode* nil)
  59 (defparameter *black-list-mode* nil)
  60
  61 (defvar *white-list* nil)
  62 (defvar *black-list* nil)
  63
  64 ;TODO: explore if these two can be written with a macro.
  65 (defun black-list (lisp-tweets)
  66   "Remove a tweet if the user is a member of *black-list*"
  67   (if *black-list-mode*
  68       (remove-if (lambda (x)
  69                    (member (cdr (assoc :from--user x))
  70                            *black-list* :test #'equal))
  71                  lisp-tweets)
  72       lisp-tweets))
  73
  74 (defun white-list (lisp-tweets)
  75   "Remove a tweet if the user is NOT a member of *white-list*"
  76   (if *white-list-mode*
  77       (remove-if (lambda (x)
  78                    (not (member (cdr (assoc :from--user x))
  79                                 *white-list* :test #'equal)))
  80                  lisp-tweets)
  81       lisp-tweets))
  82
  83 (defun get-tweet-element-list (lisp-tweets element)
  84   "Make a list with one element from each tweet from lisp-tweets."
  85   (mapcar (lambda (x) (cdr (assoc element x))) lisp-tweets))
  86
  87 (defun apply-lists (lisp-tweets)
  88   "Apply the functions white-list and black-list"
  89   (black-list (white-list lisp-tweets)))
  90
  91 ;Not strictly necessary... Just a reminder.
  92 (defun convert-tweets-to-json (lisp-tweets)
  93   (encode-json lisp-tweets))