This script will parse all @gifs tweets searching for gifs urls and download them.

gifs.rb

#!/usr/bin/env ruby

# This script will parse all @gifs tweets searching for gifs urls and
# download them.

# Initial disclaimer!
# This mess is gonna get raw, like sushi. So haters to the left.

# Usage:
# $ git clone https://gist.github.com/4465778.git gifs
# $ cd gifs
# $ ruby ./gifs.rb
# or
# $ curl -L https://gist.github.com/raw/4465778/1ff62de0af65a7eac7af2f665e6ebced8eff2627/gifs.rb | ruby

require 'json'
require 'open-uri'

class Gif
  attr_reader :directory, :user

  def initialize
    @user = get_user_info
    @directory = "twitter-gifs"
  end

  def download!
    set_download_directory

    if user && save_gifs_urls!
      Dir.chdir directory 
      puts "Current directory: #{Dir.pwd}"
      File.open("gifs.txt", 'r') do |gifs|
        gifs.each_line do |gif|
          download_gif gif
        end
      end
    end
  end

  private

  def save_gifs_urls!
    statuses_count = user['statuses_count'].to_i
    
    # https://dev.twitter.com/docs/api/1/get/statuses/user_timeline
    number_of_pages = ([3200, statuses_count].min/200).ceil

    puts "@gifs has #{statuses_count} status updates."

    File.open("#{directory}/gifs.txt", 'w') do |user_tweets|
      (1..number_of_pages).each do |page_number|
        tweets = open "#{statuses_url}&page=#{page_number}"
        puts "Fetching page #{page_number}"
        if tweets.status.include? '200'
          get_gifs_urls(tweets).each do |gif|
            user_tweets.write("#{Net::HTTP.get_response(URI(gif))['location']}\n")
          end
        else
          puts "Failed. Response code: #{tweets.status.to_s}"
        end
      end
    end
  end

  def download_gif url
    gif_filename = url.tr("\n",'').gsub(/^.*\//,'')
    if File.exists? gif_filename
      puts "#{gif_filename} already downloaded."
    else
      puts "Downloading: #{gif_filename}"
      open(url) do |gif|
        File.open(gif_filename,"wb") { |f| f.puts gif.read }
      end
    end
  end

  def set_download_directory
    if File.exists? directory
      puts "Using #{directory} directory for gifs downloads."
    else
      puts "Creating #{directory} directory for gifs downloads."
      Dir.mkdir directory
    end
  end

  def get_user_info
    user_json = open "http://api.twitter.com/1/users/show.json?screen_name=gifs"
    if user_json.status.include? '200'
      JSON.parse user_json.read
    else
      puts "Error: Response code is: #{user_json.status.to_s}"
      false
    end
  end

  def statuses_url
    "http://api.twitter.com/1/statuses/user_timeline.json?screen_name=gifs&trim_user=true&count=200&include_retweets=true&include_entities=true"
  end

  def get_gifs_urls tweets
    # http://24.media.tumblr.com/tumblr_lx3cwnqmaW1r154eho1_500.gif
    tweets_txt = JSON.parse(tweets.read).map { |twt| twt['text'] }
    tweets_txt.inject([]) do |twts, twt|
      twts << twt.match(/http:\/\/t\.co\/.*/)[0] if twt.match(/http:\/\/t\.co\/.*/);twts
    end
  end
end

Gif.new.download!