CakePHP URL Shortener Service Tutorial

So now we have two functions in place, what next? Well we need to go back to our controller, the brain, and get some logic into it. Well this is enough for us to check whether the url exists, and generate all the necessary information to insert it into the database. So let’s do just that, insert the data into the database if it doesn’t exist already. In your shorten_controller.php file change your index action to:

function index(){
	if(!empty($this->data)){
		$md5url = $this->Shorten->md5Url($this->data['Shorten']['url']);
		if($md5url['exists'] == true){
			$this->data['Shorten']['shortcode'] = $this->Shorten->shortCode(6);
			$this->data['Shorten']['unique'] = $md5url['url'];
			if($this->Shorten->save($this->data)){
				$this->set('shorturl', $this->data['Shorten']['shortcode']);
				$this->render('short');
			}
		} else {

		}
	}
}

Confused a bit? Let me explain what is going on here, line by line. The first line is where we declare our action, you know this already, as you’ve set a route to it. Next line. This line checks whether or not form data has been submitted to the action. CakePHP stores data provided and posted from a form in the $this->data array. We check if it is set and not empty, so if you clicked Shorten! then this won’t be empty. The next line talks to the model function you set up, which generates an MD5 of the url and checks whether it exists already. This then stores it into the $md5url variable, which we use in the next line also. We check the exists element of the returned array from md5Url to see if the url existed, if it didn’t exist, we proceed!

The next two lines store extra information into the data array, which was set up by CakePHP. This is used to use its amazing save function, which we will use soon. We store the generated shortcode for the shortened url into the shortcode element of the Shorten element in the data array. Notice something here? shortcode just happens to be our fieldname in our database table, and Shorten just happens to be the model we set up! This is how the save function knows what to put where. We also store the md5′d url into the unique element, again, associated with the field in the database table.

It’s time to commit and save. We tell the save function to use the data in the $this->data array, which maps it to our database table. Awesome! It saves! We check if the save went through okay, and then we set up a variable with the shortened code which the view will access, very soon. We’ll talk about the render thinga a bit later on, when we’re going to work with views.

But what happens, you ask, if our url exists already? Well let’s build that into our controller logic now! We will need to run a query on the database to get more information of the existing record, especially its shorturl code. We will make our model fatter, writing a function to select the record after it has discovered that it already exists. To do this, add the following function to your shorten model:

function shortUrl($md5){
	$shorturl = $this->field('shortcode', array('unique'=>$md5));
	return $shorturl;
}

What this does is access the shortcode field and grabs a single record (the one it finds first) whereby unique matches the url’s unique md5 code. So basically, all we’re doing here is if the url exists already, grab its shortcode from the database, then pass it into the $shorturl variable to pass back to the controller, which we will use now! We’re going to do as above in the save function, store the shortcode into a variable that the view can access, so here is our else code:

$this->set('shorturl', $this->Shorten->shortUrl($md5url['url']));
$this->render('short');

So our index action now looks like:

function index(){
	if(!empty($this->data)){
		$md5url = $this->Shorten->md5Url($this->data['Shorten']['url']);
		if($md5url['exists'] == true){
			$this->data['Shorten']['shortcode'] = $this->Shorten->shortCode(6);
			$this->data['Shorten']['unique'] = $md5url['url'];
			if($this->Shorten->save($this->data)){
				$this->set('shorturl', $this->data['Shorten']['shortcode']);
				$this->render('short');
			}
		} else {
			$this->set('shorturl', $this->Shorten->shortUrl($md5url['url']));
			$this->render('short');
		}
	}
}

What’s this render thing you added and didn’t tell us anything about? Well render changes our default view file to something else. So instead of the view file being the default index.ctp which is named after the action, we changed it to be short.ctp. We did this because we want to display the same action, only replace the form with the shortened url.

The set function shows up again, and it does just that, sets the shortcode-code into the shorturl which the view will use! Let’s add some display logic for our view now