Getting Started With A Templating System (Ruby on Rails)
This entry is based on the Building Browsergames entry: Getting Started With A Templating System (PHP)
Since we’re using Ruby on Rails, we’re don’t have to select a templating system, there’s one already built into Rails itself. It offers many different features to make it easy to build web pages out of parts, cache parts of pages or whole pages, etc. As with most (probably all) parts of Rails, alternatives are available to what’s built in but you’ll be satisfied with what’s already there for quite a while.
I particularly want to amplify something Luke said in the original posting. He thought a lot of developers were fans of developing their own templating systems. Wow. If that is in fact true, then you are seriously misguided if you go down that path. What’s built into Rails and the Smarty templating system Luke used for his PHP work is more than enough to get your pages done. Do not waste your time on side projects like building a templating system, use the time to improve your overall programming skills or build your game. If you do, you might be one of the few percent who actually finishes a project and others get to play it.
Using Rails Views
The design of Rails is already about separating the view which builds our HTML from the controller which connects the model to the view. So displaying the user’s name in the view is as simple as adding some code like the following to the already existing app/views/welcome/index.html.erb:
&lt;%= render :partial =&gt; 'users/user_bar' %&gt; &lt;% if flash[:notice] %&gt; &lt;%= h flash[:notice] %&gt; &lt;% end %&gt; &lt;h1&gt;Welcome To The Game&lt;/h1&gt; &lt;% if logged_in? %&gt; &lt;p&gt;Hello, &lt;%= @current_user.login %&gt;!&lt;/p&gt; &lt;% end %&gt;
It’s the same as it was before except that we’ve added the section at the end that checks to see if we’re logged in and greets us if we are. Now, as long as the controller method that is called for this page sets up a @current_user variable the view will pull the login out of it and display it within the page. The restful_authentication plugin provides us with an easy to use function to check if the user is logged in or not and put the user’s info into the @current_user variable if he/she is. We’ll call that from our controller (app/controllers/welcome_controller.rb) in the index function (remember, the flow of a user’s page request always goes to the controller first to set everything up and then to the view from there).
def index current_user end
If you recall from before, the old index method didn’t do anything. Now it calls the function which will fill in the @current_user variable before the index.html.erb file gets used to generate the view. At this point if you login you should find that everything works nicely.
By this point we’ve seen that the templating code (in the .html.erb files) gives us the ability to include partials pages to reuse sections of HTML, pull data from variables, and even conditionally show or not show parts of the page.
To learn more about the functions that restful_authentication makes available to you, look in the file lib/authenticated_system.rb. There are several functions in there to help you determine whether or not the user is logged in, restrict pages from users who aren’t yet logged in, etc.