social_services.rb

require "ftools"
require "net/http"
require "rexml/document"
require "timeout"
require "uri"

# Methods for retrieving social data from services including Flickr, Last.fm and Twitter.
module SocialServices
	def get_recently_uploaded_from_flickr(limit)
		recently_uploaded = []
		response = get_response_from_remote("<FLICKR FEED URL>", 2, 5)
		if response
			REXML::Document.new(response.body).elements.to_a("feed/entry").each_with_index do |uploaded, count|
				if count < limit
					uploaded_elements = {}
					uploaded_elements[:title] = uploaded.elements["title"].text
					uploaded_elements[:url] = uploaded.elements["link"].attributes["href"]
					uploaded_elements[:image_path] = get_image_from_remote_and_crop("/flickr", 60, uploaded.elements["content"].text.match(/img.*(jpg|jpeg|png)/).to_s.match(/http.*/).to_s, 1, 5)
					recently_uploaded << uploaded_elements
				else
					break
				end
			end
		end
		return recently_uploaded		
	end
	
	# http://www.last.fm/api/show?service=278
	def get_recently_listened_to_from_lastfm(limit)
		recently_listened_to = []
		response = get_response_from_remote("http://ws.audioscrobbler.com/2.0/?method=user.getrecenttracks&user=< USER >&api_key=< API_KEY >&limit=#{ limit }", 2, 5)
		if response
			xml_document = REXML::Document.new(response.body)
			if xml_document.elements["lfm[@status = 'ok']"]
				xml_document.each_element("lfm/recenttracks/track") do |track|
					track_elements = {}
					%w(artist name album url date).each do |tag|
						if track.elements[tag]
							track_elements[tag.intern] = track.elements[tag].text
						end
					end
					image_path = get_image_from_remote_and_crop("/lastfm", 60, track.elements["image[@size = 'large']"].text, 1, 5)
					if image_path
						track_elements[:image_path] = image_path
					else
						track_elements[:image_path] = "/images/defaults/lastfm.png"
					end
					recently_listened_to << track_elements
				end
			end
		end
		return recently_listened_to
	end

	# http://apiwiki.twitter.com/REST+API+Documentation#usertimeline
	def get_recent_statuses_from_twitter(limit)
		recent_statuses = []
		response = get_response_from_remote("http://twitter.com/statuses/user_timeline/< USERNAME >.xml?count=#{ limit }", 2, 5)
		if response
			xml_document = REXML::Document.new(response.body)
			if xml_document.elements["statuses[@type = 'array']"]
				xml_document.each_element("statuses/status") do |status|
					status_elements = {}
					%w(created_at text in_reply_to_status_id in_reply_to_user_id).each { |tag| status_elements[tag.intern] = status.elements[tag].text }
					recent_statuses << status_elements
				end
			end
		end
		return recent_statuses
	end
	
	private
	
		def get_response_from_remote(url, retry_count, timeout_in_seconds)
			begin
				url = URI.parse(url)
				timeout(timeout_in_seconds) do
					Net::HTTP.start(url.host) do |session|
						if url.query
							response = session.get(url.path + "?" + url.query, { "User-Agent" => "Ruby/#{ VERSION } (#{ RUBY_PLATFORM })" })
						else
							response = session.get(url.path)
						end
						if response.is_a? Net::HTTPSuccess
							return response
						else
							RAILS_DEFAULT_LOGGER.error("ERROR #{ response.class } in SocialServices.get_xml_from_remote, URL: #{ url }")
							return nil
						end
					end
				end
			rescue Exception => exception
				if retry_count > 0
					retry_count -= 1
					retry
				else
					RAILS_DEFAULT_LOGGER.error("ERROR #{ exception.class } in SocialServices.get_xml_from_remote, URL: #{ url }, Message: #{ exception.message }")
					return nil
				end
			end
		end
		
		def get_image_from_remote_and_crop(directory, size, url, retry_count, timeout_in_seconds)
			if url
				file_name = "/" + URI.parse(url).path.gsub("/", "")
				public_directory = "/images/social_services" + directory
				absolute_directory = Rails.root + "/public" + public_directory
				if File.file? absolute_directory + file_name
					return public_directory + file_name
				else
					response = get_response_from_remote(url, retry_count, timeout_in_seconds)
					if response
						begin
							File.open(absolute_directory + file_name, "w") { |image| image.write(response.body) }
							ImageScience.with_image(absolute_directory + file_name) do |image|
								image.cropped_thumbnail(size) { |cropped_image| cropped_image.save(absolute_directory + file_name) }
							end
							return public_directory + file_name
						rescue Exception => exception
							if exception.is_a? Errno::ENOENT
								RAILS_DEFAULT_LOGGER.info("INFO Errno::ENOENT in SocialServices.get_image_from_remote_and_crop. Message: #{ exception.message }. Attempting to create directory and retry")
								File.makedirs(absolute_directory)
								retry
							else
								RAILS_DEFAULT_LOGGER.error("ERROR #{ exception.class } in SocialServices.get_image_from_remote_and_crop. Message: #{ exception.message }")
							end
						end
					end
				end
			end
			return nil
		end
end