Question

Drupal has a function called “drupal_is_front_page“. Does YII have something similar to deal with navigation in this way?

Answer 1

Unfortunately not. And while the information needed to piece this together is available, doing so is really more pain than it should be.

To begin with, the front page is defined by the CWebApplication::defaultController property, which can be configured as discussed in the definitive guide. But there’s a big issue here: defaultController can in reality be any of the following:

1. a bare controller name, e.g. site
2. a module/controller pair, e.g. module/site
3. a controller/action pair, e.g. site/index
4. a module/controller/action tuple, e.g. module/site/index

If you have specified the defaultController as #4 (which is the same as #3 if your application does not include any modules) then everything is easy:

function is_home_page() {
    $app = Yii::app();
    return $app->controller->route == $app->defaultController;
}

The problem is that if defaultController is specified as #1 or #2 then you have to examine a lot of the runtime information to convert it to form #3 or #4 (as appropriate) so that you can then run the equality check.

Yii of course already includes code that can do this: the CWebApplication::createController method, which can accept any of the valid formats for defaultController and resolve that to a controller/action pair (where controller is dependent on the module, if applicable). But looking at the source doesn’t make you smile in anticipation.

To sum it up: you can either assume that defaultController will always be fully specified and get the job done with one line of code, or borrow code from createController to determine exactly what defaultController points to (and then use the one line of code to check for equality).

I do not recommend looking into solutions based on URLs because the whole point of routes is that different URLs can point to the same content — if you go that way, can never be sure that you have the correct result.