Question

I’m trying to modify the logic within a RESTful controller. In the current implementation, I have the following:

members_controller.rb

def create
    @team = current_team
    player = Player.find(params[:player_id])
    @member = @team.add_player(player.id)

    respond_to do |format|
      if @member.save
            format.html { redirect_to(@team, :notice => 'Member was successfully added.') }
            format.js { @current_member = @member }
            format.xml  { render :xml => @member, 
            :status => :created, :location => @member } 
      else
            format.html { redirect_to(@team, :notice => 'Member already exists.') }
            format.xml  { render :xml => @member.errors, 
            :status => :unprocessable_entity }
      end
    end
  end

team.rb

has_many :members, :dependent => :destroy

def add_player(player_id)
    current_member = members.find_by_player_id(player_id)
    if current_member
        # will not add duplicate member
    else
        current_member = members.build(:player_id => player_id)
    end
    current_member
end

This is lacking some functionality as I want to be able to control whether the member is saved by checking other attributes of the member against the player. In the current implementation, if I try to add a member that already exists, it is still getting redirected to @team with the notice ‘Member was successfully added.’, even though no member is being added. If I try to remove the redundancy by having the following, the controller adds duplicate members.

@team = current_team
@member = @team.add_player(:player_id)

Why is my current logic allowing me to not save a duplicate member, but still responding to the @member.save route? How do I control it properly?

Answer 1

Instead of

def add_player(player_id)
current_member = members.find_by_player_id(player_id)
if current_member
    # will not add duplicate member
else
    current_member = members.build(:player_id => player_id)
end
current_member
end

Try:

Member.rb

validates_uniqueness_of :player_id, :scope => :team_id

team.rb

def add_player(player_id)
    current_member = members.build(:player_id => player_id)   
    current_member
end