How to Create Custom Block and Render on template in drupal 8?

Here we are discussing simple concept for create custom Block and render on template. Just simple Steps, Please follow this.

1. We have to create folder under "/modules/custom/herobanner".
2. Inside this 'myblock' folder have to create 'info.yml' file like..

Example:
herobanner.info.yml
name: Hero Banner
type: module
description: Homepage hero banner.
core: '8.x'
package: Custom
dependencies:
  - block

 
3. Then we have to create one more folder like "/modules/herobanner/src/Plugin/Block" and create file in this folder with name of "HerobannerBlock.php".

There we will mention "Annotation meta data", that will allow us to identify the Block.
Here "HerobannerBlock" class will contain 4 methods:
build(), blockAccess(), blockForm(), blockSubmit()

4. Now we will start code in "HerobannerBlock.php" file.

<?php

namespace Drupal\herobanner\Plugin\Block;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Link;

/**
 * Provides a 'Banner' Block
 *
 * @Block(
 *   id = "banner_block",
 *   admin_label = @Translation("Banner block"),
 * )
 */

class HerobannerBlock extends BlockBase {
  /**
   * {@inheritdoc}
   */
  public function build() {
    return [
      '#markup' => $this->t('This is a custom block example.'),
    ];
  }

  /**
   * {@inheritdoc}
   */
  protected function blockAccess(AccountInterface $account) {
    return AccessResult::allowedIfHasPermission($account, 'access content');
  }

  /**
   * {@inheritdoc}
   */
  public function blockForm($form, FormStateInterface $form_state) {
    $config = $this->getConfiguration();

    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function blockSubmit($form, FormStateInterface $form_state) {
    $this->configuration['herobanner_settings'] = $form_state->getValue('herobanner_settings');
  }
}


Example:
namespace Drupal\herobanner\Plugin\Block;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Link;

/**
 * Provides a 'Banner' Block
 *
 * @Block(
 *   id = "banner_block",
 *   admin_label = @Translation("Banner block"),
 * )
 */

class HerobannerBlock extends BlockBase {
  /**
   * {@inheritdoc}
   */
  public function build() {
  /**
   * Read homepage_banner_products homepage_hero_banner
   */
    $query = \Drupal::entityQuery('taxonomy_term');
    $query->condition('vid', "homepage_banner_products");   
    $query->sort('weight','ASC');
    $tids = $query->execute();
       
    $homepage_banner_products_terms = \Drupal\taxonomy\Entity\Term::loadMultiple($tids);
    $i=0;
    $product_slider = '';
    foreach ($homepage_banner_products_terms as $term) {   
                
        $product_image_path = $term->field_image->entity->getFileUri();   
        $img_url = file_create_url($product_image_path);
        $product_image = $term->get('field_image')->getValue();
        $prdct_alt = $product_image[0]['alt'];
        $new_window = $term->get('field_open_in_new_window')->getValue();
        $target = (isset($new_window[0]) && $new_window[0]['value'] == 1)?'target="_blank"':'';               
       
        $enddate = $term->get('field_end_date')->getValue();       
       
        $curdate = date('Y-m-d');
        if($enddate >= $curdate){
        $active_class = ($i == 0)?'active':'';       
          
            $product_slider.='<div class="item '.$active_class.'">
                                <div class="item-inner">
                                    <h2>'.$term->name->value.'</h2>
                                    <div class="productthumb"><img src="'.$img_url.'" alt="'.$prdct_alt.'"></div>
                                    '.$term->description->value.'
                                    <a href="'.$term->field_title->value.'" '.$target.' class="linkBtn mdhbanner">'.$term->field_support_option_title->value.'<span class="icon-icon_link"></span></a>
                                </div>
                            </div>';       
       
            $i++;   
           
        }
    }
   
    $html = '<div class="arc-container layer-3 layer" data-depth=".5" data-type="parallax">
            <div class="arc-circle">
                <div class="featuredproduct">
                    <div class="pop-scroll-outer">
                        <div class="pop-scroll">
                            <div class="slidercontrol">
                                <a type="button" class="slick-prev slickbutton carousel-control" href="javascript:void(0)">
                                    <span class="icon-icon_link icon-flip" href="#myCarousel" data-slide="prev"></span>
                                </a>
                                <strong>Featured Products</strong> <span class="num"></span>
                                <a type="button" class="slick-next slickbutton carousel-control" href="javascript:void(0)">
                                    <span class="icon-icon_link" href="#myCarousel" data-slide="next"></span>
                                </a>

                            </div>

                            <div id="myCarousel" class="carousel slide" data-ride="carousel" data-interval="false">
                                <div class="carousel-inner">
                                    '.$product_slider.'
                                </div>
                            </div>
                        </div>

                    </div>
                    <!--Featured Product-->
                </div>
            </div>
        </div>
    </div>';
   
    return array(
      '#markup' => $this->t($html),
    );
  }
}

?>

Now we have to install and Enable our module and then clear the cache.

Place Block

Choose Block

And Pass the 'id' of your Block in this function..

Syntax: {{ drupal_block('myblock_id') }}

Example: {{ drupal_block('banner_block') }}

After this clear the cache and get the result.


Note: If have any suggestions or issue regarding 'How to Create Custom Block and Render on template in drupal 8?' then you can ask by comments.

How to find text from URL in Twig Template drupal 8?

It is easy way to find any text in any string or url in a Twig template file, here is we have syntax structure for this problem, have a look.

Syntax:

                 {% set testvar = url('<current>') %}
                 {% if 'test' in testvar|render|render %}
                         <p>url contains "test"</p>
                 {% endif %}

Description: here we set a 'testvar' variable with contain of current page URL, and then we find a 'test' string in 'testvar' variable means in URL, if contain string then <p> tag data will print.

Example:
               {% set testvar = node.field_link.0.url %}
               {% if '/node/add' in testvar|render|render %}                               
               {% else %}
               <a href="{{ node.field_link.0.testvar }}">Read More</a>
               {% endif %} 

Description: here 'testvar' variable contain the value of that 'node.field_link.0.url' field. and we are checking/finding the '/node/add' string. if this will exist in then data will not display and in else case 'Read More' will display with that link.



Note: If have any suggestions or issue regarding 'How to find text from URL in Twig Template drupal 8?' then you can ask by comments.

How to Check the Condition in Twig Template?

It's easy process to check the condition of our 'id' exist or not for particular variable render time in Twig template.
Like we have to check any "Product type" exist or not and then variable call there, So we are giving an example:
Example 1:
{% if node.field_product_type.value not in ['0', '2', '4', '5', '7'] %}
 /*** print variable here ***/
{% endif %}

Description: Here our condition is, if Product type of node value is not in these id's ['0', '2', '4', '5', '7'], then our variable will show the result otherwise not.

Example 2:
{% set node_id = node.id %}
{% if node_id in ['216','217','9','1258'] %} 
 /*** print variable here ***/
{% endif %}

Description: Here our condition is, if node id of node is in these id's ['216','217','9','1258'], then our variable will show the result otherwise not.


Note: If have any suggestions or issue regarding 'How to Check the Condition in Twig Template?' then you can ask by comments.

How to get the Parent id from term id in drupal 8?

It's easy way to tackle this problem, Sometimes we face this issue and take the query help and get the parent id, but we have here solution for this issue.

Just write the loadParent syntax as per given instructions:

Syntax:

$term_id = $node->get('field_category')->target_id;

$term = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->load($term_id);

$parentids = $term->parent->target_id;

OR

 $parent = \Drupal::entityTypeManager()->getStorage('taxonomy_term')->loadParents($term_id);   // here term_id is child term id
 $parent = reset($parent); //reset the parent array
 $parentids = $parent->id();    //get the parent id  


Note: If have any suggestions or issue regarding 'How to get the Parent id from term id in drupal 8?' then you can ask by comments.

How to encode url in drupal 8?

It's a easy way to encode url in drupal 8 twig template. We just have to follow the simple steps:
Step 1. First create a variable like given example.

Example:
{% set return_url = render_var(url('<front>')) ~ 'contact?msg=success&region=americas' %}

Description: here
   return_url is the variable name and
   url('<front>') is the front page url and
   contact?msg=success&region=americas this section we are concating with " ~ " Tilde sign and
   render_var is the render that full url.

Step 2. Now we have to pass the url in src like given example.

Example: https://www.google.com?Return_URL={{ return_url|url_encode}}

Description: So just call the "return_url" with "url_encode" function in url query string. That will return the encoded url.


Note: If have any suggestions or issue regarding 'How to encode url in drupal 8?' then you can ask by comments. 

How to migrate content by admin in drupal 8?

It is easy way to import content in any content type in drupal 8 by admin. We just have to download module and install in our project that is `CSV Importer`. The link of `csv importer` module on drupal Org site is..

CSV Importer Download Link: https://www.drupal.org/project/csv_importer

Description: It supports Taxonomy, Users, Content migration service and this module is also available for Drupal 8.
We are going to attach demo CSV file format as screenshot in this article for better understanding.
Now going to add some screenshots for understanding module.

CSV Importer Module

Install Module process

Module Configuration

Choose entity for migrate

Now we can Choose here Entity type[Content type, Taxonomy, Users] and then content type dropdown will come automatically and in case of taxonomy then taxonomy's dropdown list will come.
Then Upload CSV file same as attached under file screenshot and upload content with easy way.

Demo CSV file Format:

Demo CSV file format

Note: If have any suggestions or issue regarding 'How to migrate content by admin in drupal 8?' then you can ask by comments.  

How to dynamically clear cache in drupal 8?

It's a easy way to clear or remove cache with using this simple code.

Code: \Drupal::service('page_cache_kill_switch')->trigger();

Description: Simple write this code on your function and when your code will hit or run on any page this page cache will automatically triggered and clear.


Note: If have any suggestions or issue regarding 'How to dynamically clear cache in drupal 8?' then you can ask by comments.