A modification for CodeIgniter 2.x to support rails or cakePHP style layouts. It's been tested and works in 2.0.3-2.1.
For those new to this, a layout contains presentation code that wraps around the current view view (think: template). Anything you want to see in all of your views should be placed in a layout.
Layout files should be placed in /applications/views/layouts/... You can specify which layout is to be used in your controller. i.e.
<?
// in applciation/controllers/welcome.php
//
class Welcome extends MY_Controller {
function index() {
// loads layout application/views/layouts/my_new_layout.phtml
//
$this->layout = 'my_new_layout';
$this->load->view('index');
}
}When you create a layout, you need to tell it where to place the code for your views. To do so, make sure your layout includes a $yield variable. Also, please note that all layouts are expecting a .phtml extension (this is on purpose to try and remind developers that these should be super light on php logic).
Here's an example of what a default layout might look like:
<!-- in application/layouts/default.phtml -->
<html>
<title></title>
<body>
<h1>Header</h1>
<?php echo $yield; ?>
</body>
</html>If you'd like to pass variables into your layout, you can via the MY_Controller's setLayoutVar() method. Any variables set here will be exposed to the layout's scope.
For example:
<?
// in applciation/controllers/welcome.php
//
class Welcome extends MY_Controller {
function index() {
$this->layout = 'my_new_layout';
$this->setLayoutVar('body_class', 'foo');
$this->setLayoutVar('footer', $this->load->view('footer', null, 1));
$this->load->view('index');
}
}<!-- in application/view/layout/my_new_layout.phtml -->
...
<body class="<?php echo $body_class; ?>">
<h1>Header</h1>
<?php echo $yield; ?>
<?php echo $footer; ?>
</body>To turn off a layout for a particular action (i.e. an AJAX request), you can set the layout member to be null, or string literal 'none'.
<?
// in applciation/controllers/welcome.php
//
class Welcome extends MY_Controller {
function json_action() {
// setting the layout to none, will prevent it from rendering one
//
$this->layout = 'none';
// now we can echo our JSON payload, or whatever.
//
echo json_encode(array('foo' => 'bar'));
exit();
}
}You can also play around with creating JSON or XML layout templates as well. This can be super useful for normalizing your async return values.
When using the layouts hook, you'll no longer be able to call echo() from within a controller action. Well, you can, but there's some funny timings, and anything you echo will appear above the layout. And, really, as per MVC conventions, you should be using views anyway!
Clone the project, and add the files into your CI project. In application/config/config.php, the only change from the default config is to turn the hooks on (line 94).
And then in application/config/hooks.php you can see how we're wiring up the layouts to CI's display_override event.
In application/hooks/layout.php is where all the magic happens of loading and executing the layout.
For the application/core/MY_Controller, the logic is in place for setting a default layout, and handing the setLayoutVar() method.