This view uses Embedded Ruby to display the user’s name and email address, assuming the existence of an instance variable called @user. Of course, eventually the real user show page will look very different, and won’t display the email address publicly. In order to get the user show view to work, we need to define an @user variable in the corresponding show action in the Users controller. As you might expect, we use the find method on the User model (Section 6.1.4) to retrieve the user from the database, as shown in Listing 7.5.

Here we’ve used params to retrieve the user id. When we make the appropriate request to the Users controller, params[:id] will be the user id 1, so the effect is the same as the find method

we saw in Section 6.1.4. (Technically, params[:id] is the string "1", but find is smart enough to convert this to an integer.) With the user viewand action defined, the URI/users/1works perfectly (Figure 7.6). Note that the debug information in Figure 7.6 confirms the value of params[:id]:  

This is why the code

in Listing 7.5 finds the user with id 1.