Create checkin from foursquare push

foursquare_push.rb

  def foursquare_push
    # params[:checkin] is a foursquare-provided JSON object
    checkin_hash = ActiveSupport::JSON.decode(params[:checkin])
    
    # Look up the user based on foursquare ID
    user = User.find_by_foursquare_id(checkin_hash["user"]["id"])

    if user
      # Create a new checkin, set its parameters from the hash
      # foursquare sent us. Check for dups 
      c = Checkin.find_by_checkin_id(checkin_hash["id"])
      c = Checkin.new( :user => user, :action => user.action ) unless c
      c.set_checkin_data checkin_hash
      c.save
      c.process_checkin
    end
    
    # Tell foursquare thanks!    
    # Foursquare is pushing us data for a user we don't know about
    render :text => "success"
  end