The Bakery Everything CakePHP

Introduction

How many times you wondered how great it would be if your URLs didn't look so much like:

http://www.server.com/posts/view/1058
But more like:

http://www.server.com/posts/view/my_first_post
Jeez even the bakery could use something like this :)

On this article I'm going to show you how easy it is to make your model records be accessed by friendly URLs. In fact, we're going to modify CakePHP's popular The Cake Blog Tutorial to allow friendly URLs.

Modify your Table

The first thing we'll need to do is to add a field called url that will hold a unique value for each post. On the blog tutorial you can see that we have a table called posts with several fields. Run your database administration and issue the following command:

Download code ALTER TABLE `posts` ADD `url` VARCHAR(255) NOT NULL AFTER `id`;
We just added a field called `url` after field `id`.

Create your AppModel

The next step will be to add the logic on the model to allow the automatic creation of a unique value for the field url based on the post title.

Since we may want to add friendly URLs to other models we're going to insert the appropiate methods to our AppModel, rather than adding it to the Posts model. So create a file named app_model.php on your /app directory. It should look like this:

Model Class:

Download code <?php 
class AppModel extends Model
{
    function getUniqueUrl($string, $field)
    {
        // Build URL
        
        $currentUrl = $this->_getStringAsURL($string);
        
        // Look for same URL, if so try until we find a unique one
        
        $conditions = array($this->name . '.' . $field => 'LIKE ' . $currentUrl . '%');
        
        $result = $this->findAll($conditions, $this->name . '.*', null);
        
        if ($result !== false && count($result) > 0)
        {
            $sameUrls = array();
            
            foreach($result as $record)
            {
                $sameUrls[] = $record[$this->name][$field];
            }
        }
    
        if (isset($sameUrls) && count($sameUrls) > 0)
        {
            $currentBegginingUrl = $currentUrl;
    
            $currentIndex = 1;
    
            while($currentIndex > 0)
            {
                if (!in_array($currentBegginingUrl . '_' . $currentIndex, $sameUrls))
                {
                    $currentUrl = $currentBegginingUrl . '_' . $currentIndex;
    
                    $currentIndex = -1;
                }
    
                $currentIndex++;
            }
        }
        
        return $currentUrl;
    }
    
    function _getStringAsURL($string)
    {
        // Define the maximum number of characters allowed as part of the URL
        
        $currentMaximumURLLength = 100;
        
        $string = strtolower($string);
        
        // Any non valid characters will be treated as _, also remove duplicate _
        
        $string = preg_replace('/[^a-z0-9_]/i', '_', $string);
        $string = preg_replace('/_[_]*/i', '_', $string);
        
        // Cut at a specified length
        
        if (strlen($string) > $currentMaximumURLLength)
        {
            $string = substr($string, 0, $currentMaximumURLLength);
        }
        
        // Remove beggining and ending signs
        
        $string = preg_replace('/_$/i', '', $string);
        $string = preg_replace('/^_/i', '', $string);
        
        return $string;
    }
}
?>
The method _getStringAsURL() converts a string to a friendly URL form. For example, running:

Download code _getStringAsURL('Hello CakePHP baker, baking hard?');
Will be transformed into:

Download code hello_cakephp_baker_baking_hard
The method getUniqueUrl takes two parameters:

1. $string: the string that will be used to generate the URL. On our case this is the post title.
2. $field: the field that will hold the generated URL. On our case this is url.

It will start by generating the friendly URL version of the post title and then look over the table to see if the generated URL was assigned to another record. If so, it will add _1, _2, _3, etc. until it finds a unique version.

It is important to know that we will only generate a friendly URL when the post is being inserted to the database, not when it is being modified. This is a common procedure on friendly URL generation since you never know if you already have incoming links to the generated URL.

Modify your Model

Now we are ready to modify the Post model to allow the creation of a friendly URL when inserting a new post. As The Cake Blog Tutorial shows the latest version of the file /app/models/post.php looked like this:

Model Class:

Download code <?php 
class Post extends AppModel
{
    var $name = 'Post';
    
    var $validate = array(
        'title'  => VALID_NOT_EMPTY,
        'body'   => VALID_NOT_EMPTY
    );
}
?>
Change it so we can add the URL generation. It should now look like this:

Model Class:

Download code <?php 
class Post extends AppModel
{
    var $name = 'Post';
    
    var $validate = array(
        'title'  => VALID_NOT_EMPTY,
        'body'   => VALID_NOT_EMPTY
    );
    
    function beforeSave()
    {
        if (empty($this->id))
        {
            $this->data[$this->name]['url'] = $this->getUniqueUrl($this->data[$this->name]['title'], 'url');
        }
        
        return true;
    }
}
?>
As you can see we just added a method called beforeSave(), which is a function that CakePHP automatically calls before saving a model instance to the database. There, we start by checking that the ID for the record has not been set. This is the case when inserting a new post. We then set the value of the url field to be the friendly URL version of the value of the field title.

Now, every time a new post is being inserted to your database a unique friendly URL will be generated.

Modify your View

The next step is to modify the way we are building the links to each post. Edit your file /app/views/posts/index.thtml and look for the following expression:

Download code echo $html->link($post['Post']['title'], "/posts/view/".$post['Post']['id']);
Change it to:

Download code echo $html->link($post['Post']['title'], "/posts/view/".$post['Post']['url']);

Modify your Controller

Last but not least we need to change our controller so it will receive the URL rather than the ID of the post the user is trying to access. Edit your file /app/controllers/posts_controller.php and look for the following block of code:

Download code function view($id = null)
{
    $this->Post->id = $id;
    $this->set('post', $this->Post->read());
}
Change this code to look like this:

Download code function view($url)
{
    $post = $this->Post->findByUrl($url);
    
    $this->set('post', $post);
}

Feedback

If you have any comments / questions try to add them (if you think they'll add value to other bakers) as comments on this page. If you want to contact me directly try:

email: mariano@cricava.com blog: http://www.marianoiglesias.com.ar
Otherwise just drop a question on Cake's Google Group mentioning this tutorial on the subject since I am constantly reading/writing on the group.

Got your CakeSchwag? I bought myself the Baseball Jersey and the Khaki Cap. I have to wait till December 29 for them to arrive (I asked a friend from the states to buy them and bring it to me down here... Argentina is a long way from the US.) What are you waiting for?

Remember, smart coders answer ten questions for every question they ask. So be smart, be cool, and share your knowledge.
BAKE ON