Is callback needed for loops containing API requests?

Question

I'm on Rails and I use Koala in a cron job to import all comments Facebook.

Is it ok to use a for loop where each time I make a request and store the response? Or there is a risk for which the for restart before I get a response from Facebook all gets messed up?

In other words: Does the loop wait for the response or do I need a callback function?

Here is the loop:

def self.import_comments
    # Access Facebook API
    facebook = Feed.get_facebook_access

    # Run 190 queries per cron job
    for i in 1..190

        id_of_latest_feed         = Feed.get_latest['fb_id']
        id_of_latest_feed_checked = Option.get_feed_needle

        # Check if there are more recent feeds than the latest checked
        if id_of_latest_feed != id_of_latest_feed_checked
            # Get the facebook id of the feed which comes after the latest checked
            latest_feed_checked  = Feed.where( fb_id: id_of_latest_feed_checked ).first
            this_date            = latest_feed_checked['fb_updated_time']
            feed_to_check        = Feed.get_older_than( this_date )

            unless feed_to_check.nil?
                # Get the ID of the feed to check
                fb_id = feed_to_check['fb_id']
                # Update needle
                Option.update_feed_needle_to( fb_id )

                # -------- REQUEST! --------- #
                # Get comments from Facebook
                @comments = facebook.get_object("#{ fb_id }/comments?filter=stream")

                # Save each comment
                @comments.each do |comment|
                    if Comment.exists?(fb_id: comment['id'])
                        # don't  do anyhting
                    else
                        # save the comment
                    end
                end 
            end
        end
    end
end

Answer 1

Koala's get_object call is synchronous, so execution will pause and won't return to your code until the result is ready. (Unless it fails, in which case Koala raises an error).

So yes, it's safe to use like this! The for loop won't continue until the result of the previous call is ready. No callbacks needed!

(I'm basing this on the examples in the Koala wiki).