Question

Here’s code. Can anyone find why?
This program is to show photos from one’s friend’s albums.

I think this program uses facebook api 3times, so there might be important point.
But i dont have any idea about things instead of this code.

  graph = Koala::Facebook::API.new(session[:access_token])
  freegraph = Koala::Facebook::API.new

  friends = graph.get_object("me/friends")
  friendsIds = Array.new
  friends.each do |f| friendsIds << f["id"] end
  fsinfo = freegraph.get_objects(friendsIds)

  @realFriends = Array.new
  fsinfo.each do |f|
    if f[1]["gender"].present? && (f[1]["gender"] != "male")
      @realFriends << f[1]
    end
  end

  rFids = @realFriends.map do |rF| rF["id"] end

  albums = graph.get_object("albums?ids="+rFids.join(","))
  album_ids = Array.new
  albums.each do |user|
     album_ids += user[1]["data"].map do |a| a["id"] end
  end

  randAlbumIds = Array.new
  20.times do
    randAlbumIds << album_ids.at(rand(album_ids.count))
  end

  imgList = graph.get_object("photos?ids="+randAlbumIds.join(","))
  imgObjs = Array.new
  imgList.each do |img|
    imgObjs += img[1]["data"]
  end
  if params[:tags].present?
    @photos = imgObjs.select do |i| i["tags"].present? end
  else
    @photos = imgObjs
  end

Answer 1

Facebook pulls are going to be slow, that’s a given. You don’t want to do HTTP calls inside of the Rails HTTP request — also a given. So, you’ll want to move this to a background process or thread.

But I’m more concerned about your code… You wrote

 @realFriends = Array.new
  fsinfo.each do |f|
    if f[1]["gender"].present? && (f[1]["gender"] != "male")
      @realFriends << f[1]
    end
  end

  rFids = @realFriends.map do |rF| rF["id"] end

you’re looking for an array of female friend ideas. So I would do this:

@female_friend_ids = fsinfo.map {|friend| friend["id"] if friend.first["gender"] != "male"}.compact

This will return an array of friend ids who are not male. The map will return [nil, 3435, 656], and to get rid of the nils we call compact.

It’s readable, and will be faster in execution and reduce garbage collection time.

Can’t help myself. More!

randAlbumIds = Array.new
20.times do
  randAlbumIds << album_ids.at(rand(album_ids.count))
end

Should just be

random_album_ids = album_ids.shuffle.take(20)

(All this is just Ruby awesomeness)