Forms and actions

Adding new albums

We can now code up the functionality to add new albums. There are two bits to this part:

• Display a form for user to provide details
• Process the form submission and store to database

We use Zend\Form to do this. The Zend\Form component manages the form and, form validation, we add a Zend\InputFilter to our Album entity. We start by creating a new class Album\Form\AlbumForm that extends from Zend\Form\Form to define our form. Create a file called AlbumForm.php in module/Album/src/Album/Form:

 namespace Album\Form;

 use Zend\Form\Form;

 class AlbumForm extends Form
 {
     public function __construct($name = null)
     {
         // we want to ignore the name passed
         parent::__construct('album');

         $this->add(array(
             'name' => 'id',
             'type' => 'Hidden',
         ));
         $this->add(array(
             'name' => 'title',
             'type' => 'Text',
             'options' => array(
                 'label' => 'Title',
             ),
         ));
         $this->add(array(
             'name' => 'artist',
             'type' => 'Text',
             'options' => array(
                 'label' => 'Artist',
             ),
         ));
         $this->add(array(
             'name' => 'submit',
             'type' => 'Submit',
             'attributes' => array(
                 'value' => 'Go',
                 'id' => 'submitbutton',
             ),
         ));
     }
 }

Within the constructor of AlbumForm we do several things. First, we set the name of the form as we call the parent’s constructor. We then set the form’s method, in this case, post. Finally, we create four form elements: the id, title, artist, and submit button. For each item we set various attributes and options, including the label to be displayed.

We also need to set up validation for this form. In Zend Framework 2 this is done using an input filter, which can either be standalone or defined within any class that implements the InputFilterAwareInterface interface, such as a model entity. In our case, we are going to add the input filter to the Album class, which resides in the Album.php file in module/Album/src/Album/Model:

 namespace Album\Model;

 // Add these import statements
 use Zend\InputFilter\InputFilter;
 use Zend\InputFilter\InputFilterAwareInterface;
 use Zend\InputFilter\InputFilterInterface;

 class Album implements InputFilterAwareInterface
 {
     public $id;
     public $artist;
     public $title;
     protected $inputFilter;                       // <-- Add this variable

     public function exchangeArray($data)
     {
         $this->id     = (isset($data['id']))     ? $data['id']     : null;
         $this->artist = (isset($data['artist'])) ? $data['artist'] : null;
         $this->title  = (isset($data['title']))  ? $data['title']  : null;
     }

     // Add content to these methods:
     public function setInputFilter(InputFilterInterface $inputFilter)
     {
         throw new \Exception("Not used");
     }

     public function getInputFilter()
     {
         if (!$this->inputFilter) {
             $inputFilter = new InputFilter();

             $inputFilter->add(array(
                 'name'     => 'id',
                 'required' => true,
                 'filters'  => array(
                     array('name' => 'Int'),
                 ),
             ));

             $inputFilter->add(array(
                 'name'     => 'artist',
                 'required' => true,
                 'filters'  => array(
                     array('name' => 'StripTags'),
                     array('name' => 'StringTrim'),
                 ),
                 'validators' => array(
                     array(
                         'name'    => 'StringLength',
                         'options' => array(
                             'encoding' => 'UTF-8',
                             'min'      => 1,
                             'max'      => 100,
                         ),
                     ),
                 ),
             ));

             $inputFilter->add(array(
                 'name'     => 'title',
                 'required' => true,
                 'filters'  => array(
                     array('name' => 'StripTags'),
                     array('name' => 'StringTrim'),
                 ),
                 'validators' => array(
                     array(
                         'name'    => 'StringLength',
                         'options' => array(
                             'encoding' => 'UTF-8',
                             'min'      => 1,
                             'max'      => 100,
                         ),
                     ),
                 ),
             ));

             $this->inputFilter = $inputFilter;
         }

         return $this->inputFilter;
     }
 }

The InputFilterAwareInterface defines two methods: setInputFilter() and getInputFilter(). We only need to implement getInputFilter() so we simply throw an exception in setInputFilter().

Within getInputFilter(), we instantiate an InputFilter and then add the inputs that we require. We add one input for each property that we wish to filter or validate. For the id field we add an Int filter as we only need integers. For the text elements, we add two filters, StripTags and StringTrim, to remove unwanted HTML and unnecessary white space. We also set them to be required and add a StringLength validator to ensure that the user doesn’t enter more characters than we can store into the database.

We now need to get the form to display and then process it on submission. This is done within the AlbumController’s addAction():

 // module/Album/src/Album/Controller/AlbumController.php:

 //...
 use Zend\Mvc\Controller\AbstractActionController;
 use Zend\View\Model\ViewModel;
 use Album\Model\Album;          // <-- Add this import
 use Album\Form\AlbumForm;       // <-- Add this import
 //...

     // Add content to this method:
     public function addAction()
     {
         $form = new AlbumForm();
         $form->get('submit')->setValue('Add');

         $request = $this->getRequest();
         if ($request->isPost()) {
             $album = new Album();
             $form->setInputFilter($album->getInputFilter());
             $form->setData($request->getPost());

             if ($form->isValid()) {
                 $album->exchangeArray($form->getData());
                 $this->getAlbumTable()->saveAlbum($album);

                 // Redirect to list of albums
                 return $this->redirect()->toRoute('album');
             }
         }
         return array('form' => $form);
     }
 //...

After adding the AlbumForm to the use list, we implement addAction(). Let’s look at the addAction() code in a little more detail:

 $form = new AlbumForm();
 $form->get('submit')->setValue('Add');

We instantiate AlbumForm and set the label on the submit button to “Add”. We do this here as we’ll want to re-use the form when editing an album and will use a different label.

 $request = $this->getRequest();
 if ($request->isPost()) {
     $album = new Album();
     $form->setInputFilter($album->getInputFilter());
     $form->setData($request->getPost());
     if ($form->isValid()) {

If the Request object’s isPost() method is true, then the form has been submitted and so we set the form’s input filter from an album instance. We then set the posted data to the form and check to see if it is valid using the isValid() member function of the form.

 $album->exchangeArray($form->getData());
 $this->getAlbumTable()->saveAlbum($album);

If the form is valid, then we grab the data from the form and store to the model using saveAlbum().

 // Redirect to list of albums
 return $this->redirect()->toRoute('album');

After we have saved the new album row, we redirect back to the list of albums using the Redirect controller plugin.

 return array('form' => $form);

Finally, we return the variables that we want assigned to the view. In this case, just the form object. Note that Zend Framework 2 also allows you to simply return an array containing the variables to be assigned to the view and it will create a ViewModel behind the scenes for you. This saves a little typing.

We now need to render the form in the add.phtml view script:

 <?php
 // module/Album/view/album/album/add.phtml:

 $title = 'Add new album';
 $this->headTitle($title);
 ?>
 <h1><?php echo $this->escapeHtml($title); ?></h1>
 <?php
 $form->setAttribute('action', $this->url('album', array('action' => 'add')));
 $form->prepare();

 echo $this->form()->openTag($form);
 echo $this->formHidden($form->get('id'));
 echo $this->formRow($form->get('title'));
 echo $this->formRow($form->get('artist'));
 echo $this->formSubmit($form->get('submit'));
 echo $this->form()->closeTag();

Again, we display a title as before and then we render the form. Zend Framework provides some view helpers to make this a little easier. The form() view helper has an openTag() and closeTag() method which we use to open and close the form. Then for each element with a label, we can use formRow(), but for the two elements that are standalone, we use formHidden() and formSubmit().

Alternatively, the process of rendering the form can be simplified by using the bundled formCollection view helper. For example, in the view script above replace all the form-rendering echo statements with:

 echo $this->formCollection($form);

Note: You still need to call the openTag and closeTag methods of the form. You replace the other echo statements with the call to formCollection, above.

This will iterate over the form structure, calling the appropriate label, element and error view helpers for each element, but you still have to wrap formCollection($form) with the open and close form tags. This helps reduce the complexity of your view script in situations where the default HTML rendering of the form is acceptable.

You should now be able to use the “Add new album” link on the home page of the application to add a new album record.

Editing an album

Editing an album is almost identical to adding one, so the code is very similar. This time we use editAction() in the AlbumController:

 // module/Album/src/Album/Controller/AlbumController.php:
 //...

     // Add content to this method:
     public function editAction()
     {
         $id = (int) $this->params()->fromRoute('id', 0);
         if (!$id) {
             return $this->redirect()->toRoute('album', array(
                 'action' => 'add'
             ));
         }

         // Get the Album with the specified id.  An exception is thrown
         // if it cannot be found, in which case go to the index page.
         try {
             $album = $this->getAlbumTable()->getAlbum($id);
         }
         catch (\Exception $ex) {
             return $this->redirect()->toRoute('album', array(
                 'action' => 'index'
             ));
         }

         $form  = new AlbumForm();
         $form->bind($album);
         $form->get('submit')->setAttribute('value', 'Edit');

         $request = $this->getRequest();
         if ($request->isPost()) {
             $form->setInputFilter($album->getInputFilter());
             $form->setData($request->getPost());

             if ($form->isValid()) {
                 $this->getAlbumTable()->saveAlbum($album);

                 // Redirect to list of albums
                 return $this->redirect()->toRoute('album');
             }
         }

         return array(
             'id' => $id,
             'form' => $form,
         );
     }
 //...

This code should look comfortably familiar. Let’s look at the differences from adding an album. Firstly, we look for the id that is in the matched route and use it to load the album to be edited:

 $id = (int) $this->params()->fromRoute('id', 0);
 if (!$id) {
     return $this->redirect()->toRoute('album', array(
         'action' => 'add'
     ));
 }

 // Get the album with the specified id.  An exception is thrown
 // if it cannot be found, in which case go to the index page.
 try {
     $album = $this->getAlbumTable()->getAlbum($id);
 }
 catch (\Exception $ex) {
     return $this->redirect()->toRoute('album', array(
         'action' => 'index'
     ));
 }

params is a controller plugin that provides a convenient way to retrieve parameters from the matched route. We use it to retrieve the id from the route we created in the modules’ module.config.php. If the id is zero, then we redirect to the add action, otherwise, we continue by getting the album entity from the database.

We have to check to make sure that the Album with the specified id can actually be found. If it cannot, then the data access method throws an exception. We catch that exception and re-route the user to the index page.

 $form = new AlbumForm();
 $form->bind($album);
 $form->get('submit')->setAttribute('value', 'Edit');

The form’s bind() method attaches the model to the form. This is used in two ways:

• When displaying the form, the initial values for each element are extracted from the model.
• After successful validation in isValid(), the data from the form is put back into the model.

These operations are done using a hydrator object. There are a number of hydrators, but the default one is Zend\Stdlib\Hydrator\ArraySerializable which expects to find two methods in the model: getArrayCopy() and exchangeArray(). We have already written exchangeArray() in our Album entity, so just need to write getArrayCopy():

 // module/Album/src/Album/Model/Album.php:
 // ...
     public function exchangeArray($data)
     {
         $this->id     = (isset($data['id']))     ? $data['id']     : null;
         $this->artist = (isset($data['artist'])) ? $data['artist'] : null;
         $this->title  = (isset($data['title']))  ? $data['title']  : null;
     }

     // Add the following method:
     public function getArrayCopy()
     {
         return get_object_vars($this);
     }
 // ...

As a result of using bind() with its hydrator, we do not need to populate the form’s data back into the $album as that’s already been done, so we can just call the mappers’ saveAlbum() to store the changes back to the database.

The view template, edit.phtml, looks very similar to the one for adding an album:

 <?php
 // module/Album/view/album/album/edit.phtml:

 $title = 'Edit album';
 $this->headTitle($title);
 ?>
 <h1><?php echo $this->escapeHtml($title); ?></h1>

 <?php
 $form = $this->form;
 $form->setAttribute('action', $this->url(
     'album',
     array(
         'action' => 'edit',
         'id'     => $this->id,
     )
 ));
 $form->prepare();

 echo $this->form()->openTag($form);
 echo $this->formHidden($form->get('id'));
 echo $this->formRow($form->get('title'));
 echo $this->formRow($form->get('artist'));
 echo $this->formSubmit($form->get('submit'));
 echo $this->form()->closeTag();

The only changes are to use the ‘Edit Album’ title and set the form’s action to the ‘edit’ action too.

You should now be able to edit albums.

Deleting an album

To round out our application, we need to add deletion. We have a Delete link next to each album on our list page and the naive approach would be to do a delete when it’s clicked. This would be wrong. Remembering our HTTP spec, we recall that you shouldn’t do an irreversible action using GET and should use POST instead.

We shall show a confirmation form when the user clicks delete and if they then click “yes”, we will do the deletion. As the form is trivial, we’ll code it directly into our view (Zend\Form is, after all, optional!).

Let’s start with the action code in AlbumController::deleteAction():

 // module/Album/src/Album/Controller/AlbumController.php:
 //...
     // Add content to the following method:
     public function deleteAction()
     {
         $id = (int) $this->params()->fromRoute('id', 0);
         if (!$id) {
             return $this->redirect()->toRoute('album');
         }

         $request = $this->getRequest();
         if ($request->isPost()) {
             $del = $request->getPost('del', 'No');

             if ($del == 'Yes') {
                 $id = (int) $request->getPost('id');
                 $this->getAlbumTable()->deleteAlbum($id);
             }

             // Redirect to list of albums
             return $this->redirect()->toRoute('album');
         }

         return array(
             'id'    => $id,
             'album' => $this->getAlbumTable()->getAlbum($id)
         );
     }
 //...

As before, we get the id from the matched route, and check the request object’s isPost() to determine whether to show the confirmation page or to delete the album. We use the table object to delete the row using the deleteAlbum() method and then redirect back the list of albums. If the request is not a POST, then we retrieve the correct database record and assign to the view, along with the id.

The view script is a simple form:

 <?php
 // module/Album/view/album/album/delete.phtml:

 $title = 'Delete album';
 $this->headTitle($title);
 ?>
 <h1><?php echo $this->escapeHtml($title); ?></h1>

 <p>Are you sure that you want to delete
     '<?php echo $this->escapeHtml($album->title); ?>' by
     '<?php echo $this->escapeHtml($album->artist); ?>'?
 </p>
 <?php
 $url = $this->url('album', array(
     'action' => 'delete',
     'id'     => $this->id,
 ));
 ?>
 <form action="<?php echo $url; ?>" method="post">
 <div>
     <input type="hidden" name="id" value="<?php echo (int) $album->id; ?>" />
     <input type="submit" name="del" value="Yes" />
     <input type="submit" name="del" value="No" />
 </div>
 </form>

In this script, we display a confirmation message to the user and then a form with “Yes” and “No” buttons. In the action, we checked specifically for the “Yes” value when doing the deletion.

Ensuring that the home page displays the list of albums

One final point. At the moment, the home page, http://zf2-tutorial.localhost/ doesn’t display the list of albums.

This is due to a route set up in the Application module’s module.config.php. To change it, open module/Application/config/module.config.php and find the home route:

 'home' => array(
     'type' => 'Zend\Mvc\Router\Http\Literal',
     'options' => array(
         'route'    => '/',
         'defaults' => array(
             'controller' => 'Application\Controller\Index',
             'action'     => 'index',
         ),
     ),
 ),

Change the controller from Application\Controller\Index to Album\Controller\Album:

 'home' => array(
     'type' => 'Zend\Mvc\Router\Http\Literal',
     'options' => array(
         'route'    => '/',
         'defaults' => array(
             'controller' => 'Album\Controller\Album', // <-- change here
             'action'     => 'index',
         ),
     ),
 ),

That’s it - you now have a fully working application!