Blocks, are pieces of content that can be placed anywhere on your Drupal site. in this tutorial I’ll show you how to write a simple Drupal 8 module that will display output in a block. when you’re done you will have created a new block that you can place in one or more regions.
Create a module
In Drupal 8, it is necessary to create an info.yml file that contains the metadata for every custom module. you will need to create the codimth_block.info.yml file under the modules/custom/codimth_block folder. Inside this file enter following:
name: CodimTh Block
description: Create a custom block module
package: CodimTh
type: module
core: 8.x
dependencies:
- block
Once the folder and file has been created, you can go to your Drupal dashboard and enable the custom module we have just created.
Create a Block Class
Now, we’ll create a class that will contain the logic of our block. we’ll place our CodimthBlock.php class under the modules/custom/codimth_block/src/Plugin/Block directory.
The class file should contain annotation as well. The annotation allows us to identify the bloc, also this class will contain 6 methods:
build(): required method which is expected to return a render array defining the content you want your block to display.
/**
* {@inheritdoc}
*/
public function build()
{
$config = $this->getConfiguration();
$codimth_copyright = $config['codimth_copyright'];
return [
'#markup' => "<span>$codimth_copyright</span>",
];
}
blockForm(): This method allows you to define a block configuration form using the Form API.
/**
* {@inheritdoc}
*/
public function blockForm($form, FormStateInterface $form_state)
{
$form = parent::blockForm($form, $form_state);
$config = $this->getConfiguration();
$current_year = date("Y");
$codimth_copyright = $this->t('©@year codimTh. All Rights Reserved.', [
'@year' => $current_year
]);
$form['codimth_copyright'] = [
'#type' => 'textfield',
'#title' => $this->t('Copyright'),
'#description' => $this->t('Write your copyright text.'),
'#default_value' => isset($config['codimth_copyright']) ? $config['codimth_copyright'] : $codimth_copyright,
];
return $form;
}
blockSubmit(): This method used to save a configuration, defined on the blockForm() method.
/**
* {@inheritdoc}
*/
public function blockSubmit($form, FormStateInterface $form_state)
{
parent::blockSubmit($form, $form_state);
$this->setConfigurationValue('codimth_copyright', $form_state->getValue('codimth_copyright'));
}
blockValidate(): This method used to validate block configuration form.
/**
* {@inheritdoc}
*/
public function blockValidate($form, FormStateInterface $form_state)
{
if (empty($form_state->getValue('codimth_copyright'))) {
$form_state->setErrorByName('codimth_copyright', t('This field is required'));
}
}
getCacheMaxAge(): This method used if you want to change block cache max time.
/**
* {@inheritdoc}
* return 0 If you want to disable caching for this block.
*/
public function getCacheMaxAge()
{
return 0;
}
access(): Defines a custom user access logic. It is expected to return an AccessResult object.
/**
* {@inheritdoc}
*/
public function access(AccountInterface $account, $return_as_object = FALSE)
{
return AccessResult::allowedIfHasPermission($account, 'access content');
}
Now, this is what the class file should contain in the end:
<?php
namespace Drupal\codimth_block\Plugin\Block;
use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Block\BlockPluginInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Session\AccountInterface;
/**
* Provides a 'Codimth Block' Block.
*
* @Block(
* id = "codimth_block",
* admin_label = @Translation("Codimth block"),
* category = @Translation("Codimth"),
* )
*/
class CodimthBlock extends BlockBase implements BlockPluginInterface
{
/**
* {@inheritdoc}
*/
public function build()
{
$config = $this->getConfiguration();
$codimth_copyright = $config['codimth_copyright'];
return [
'#markup' => "<span>$codimth_copyright</span>",
];
}
/**
* {@inheritdoc}
*/
public function blockForm($form, FormStateInterface $form_state)
{
$form = parent::blockForm($form, $form_state);
$config = $this->getConfiguration();
$current_year = date("Y");
$codimth_copyright = $this->t('©@year codimTh. All Rights Reserved.', [
'@year' => $current_year
]);
$form['codimth_copyright'] = [
'#type' => 'textfield',
'#title' => $this->t('Copyright'),
'#description' => $this->t('Write your copyright text.'),
'#default_value' => isset($config['codimth_copyright']) ? $config['codimth_copyright'] : $codimth_copyright,
];
return $form;
}
/**
* {@inheritdoc}
*/
public function blockSubmit($form, FormStateInterface $form_state)
{
parent::blockSubmit($form, $form_state);
$this->setConfigurationValue('codimth_copyright', $form_state->getValue('codimth_copyright'));
}
/**
* {@inheritdoc}
*/
public function blockValidate($form, FormStateInterface $form_state)
{
if (empty($form_state->getValue('codimth_copyright'))) {
$form_state->setErrorByName('codimth_copyright', t('This field is required'));
}
}
/**
* {@inheritdoc}
* return 0 If you want to disable caching for this block.
*/
public function getCacheMaxAge()
{
return 0;
}
/**
* {@inheritdoc}
*/
public function access(AccountInterface $account, $return_as_object = FALSE)
{
return AccessResult::allowedIfHasPermission($account, 'access content');
}
}
Next steps
- Clear your Drupal 8 caches. To do this I use this Drush command:
drush crif you don’t currently use Drush, I highly recommend using it, or the Drupal Console. - Now, go back to your site, and you should be able to see the block you have just created. Simply place the block to a region and it should become visible.
- I hope you found this article useful. let me know if you have any questions and I’ll be happy to answer them.
- This code can be found and downloaded from https://github.com/codimth/codimth_block.
