Alternative for :id param

Question

I have resources :users and custom_id inside users table.

I want to use link_to "user", user method choosing custom_id to provide link with this field as param.

My show action inside users_controller.rb:

...
  @user = User.find(custom_id: params[:id])
...

Answer 1

In Your form You could use:

<%= link_to @user.name, @user %>

because You already wrote in UsersController:

...
  @user = User.find(custom_id: params[:id])
...

Answer 2

A better way to manage this is via the to_param method which you can define inside a model. When you pass a model instance into a path helper, it calls this method on it, which by default returns the id. You could override it to use custom_id instead.

#in User class
def to_param
  self.custom_id
end

Now you can say

link_to "user", user_path(@user)

and it will generate html like

<a href="/users/<@user.custom_id>">user</a>

and so @user.custom_id will come through in params[:id].

You will still need to make sure that you load the user via the custom id field, rather than the id, in the controller. A common pattern is to put it into a protected method in the controller:

#in UsersController
protected

def load_user
  @user = User.find(custom_id: params[:id])
end

now you can say load_user in all the actions which load @user, or put it into a before filter for the relevant actions, which is even DRYer.