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At times in Drupal 8, a site builder needs to create a custom content type page twig file. In Drupal 8 you can't just create it like you do with other twig files that come with Drupal core , you have to register a suggestion with the theme array. Adding The functions below to your template.theme will give the developer the ability to add a twig file called page--<content_type_name>.html.twig. Overriding the default page twig file in your theme

At times you need to know the machine name of the current node. The function below will allow you to access the machine name anywhere on a page load.

/**
 * @return array|null
 */
function _access_current_node_machine_name()
{
    $nidResult = \Drupal::service('path.current')->getPath();
    $nid = explode('/', $nidResult);
    if ($nid[2] != NULL) {
        $node = \Drupal\node\Entity\Node::load($nid[2]);
        return array(
            'node_id' => $nid[2],
            'node_content_type' => $node->getType(),
        );
    }
    return NULL;
}

This function access an entity field on a node in Drupal8. It works the following way, 
 
  • Checks to see if node exists
  • Gets the current nodes NID
  • Loads the entity that is attached to the NID
  • Returns the field name of the NID 
/**
 * @param $fieldName
 * @return array of Objects
 */
function _access_a_nodes_field($fieldName) {
  if(\Drupal::routeMatch()->getParameter('node')){
    $nid = \Drupal::routeMatch()->getParameter('node');
    $node = \Drupal\node\Entity\Node::load($nid->id());
    return $node->get($fieldName)->getValue();
  }
  return NULL;
}

In Drupal 8 adding a variable so the twig layer can access it on every part of  the page can be done by using the template preprocessor, The word template in this function will be replaced by your theme name.

/**
 * Implements hook_preprocess().
 */
function template_preprocess(&$vars) {

  $vars['global_var_name'] = 'This is my var';

}

And then in the twig layer(file) where you need to use the variable.

{{global_var_name}}

This function does exactly what it says, it returns the current Drupal 8 node NID that is being requested by the user. Be careful where you call it if the page is not a node it can break the website.

/**
 * @return string
 */
function _access_node_id() {
  $node = \Drupal::routeMatch()->getParameter('node');
  return $node->id();
}

This function allows you to access a taxonomy entity fields and get the following results. The child's parents TID, the TID, and the field's string name of the TID being requested.  The results are placed into an array and custom keys can be used when being iterated over.

It works in Drupal 8 but I have access the fields using name spacing and avoided depreciated Drupal 8 functions and methods so it should be future proofed for Drupal 9 

If you have a block in Drupal 8 that needs to update its contents every time there is a page load then use the hook and code below.

On a Drupal 8 website we developed, it needed to swap out different menus depending on the page that was being requested. We found that Drupal was caching the block twig logic and the only way we could get the menus to swap was keep clearing the cache. To stop this from happening we added ['max-age'] = 0 to the right part of the block render array and all the caching on the block type stopped.

If you have an SSH terminal session open and you can't get the host computer to talk to you don't close the terminal. Exiting an SSH terminal session once it is frozen is really easy just type the command in below and restart the SSH session

Press enter in the terminal and then "~ and ."

In ubuntu 16.04 to add an online account like a Nextcloud instance got to  settings -> online accounts, If you click the add button and it does will not respond then install gnome-control-center gnome-online-accounts packages via the command line. This allows you to bypass the unity online accounts created by ubuntu  and use the gnome version. Below is the commands you need to open gnome online accounts.

$: gnome-control-center online-accounts

For anyone who is looking to access Block Fields programmatically that were created in block content in Drupal 8, this function will achieve that and will also allow you to access the files URL created in the "block content" image field if it exists. This uses Drupals new namespacing so it should work into the future with Drupal 9

I created a block type in Drupal 8's UI (structure/block/block-content/types ) and added the fields. To access block type in hook_preprocessor_html programmatically you can use the following function

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