woutersf

<?php
//If is frontpage
$on_frontpage = \Drupal::service('path.matcher')->isFrontPage();

//Match canonical route
$route_match = \Drupal::routeMatch();
if ($route_match->getRouteName() == 'entity.node.canonical') {
  // Do something..
}

woutersf

<?php

//For nodes.
if ($node = \Drupal::routeMatch()->getParameter('node')) {
  if ($node->getType() == 'article') { // Test the node type.
    $is_video = $node->get('field_is_video')->value; // Get the field value of on of the node fields.
    $class_suffix = $is_video ? 'video' : 'no-video';
    $vars['attributes']['class'][] = Html::getClass($node->getType() . '--' . $class_suffix); //Add Class to the variables.
  }
}

woutersf

<?php

///////////////////JSON

//How to render Json from Drupal 8
$response = new Response();
$response->setContent(json_encode($mydata));
$response->headers->set('Content-Type', 'application/json');
return $response;

woutersf

<?php

//If anonymous
if (\Drupal::currentUser()->isAnonymous()) {
  // Do something..
}

//if user has role
$roles = \Drupal::currentUser()->getRoles();
if(!in_array("administrator", $roles)) {

woutersf

<?php

//use...

class MySettingsForm extends ConfigFormBase {

  public function buildForm(array $form, FormStateInterface $form_state) {
    //The form
    //..

woutersf

<?php
//The submit handler function:
public function reImportAllFiles(array &$form, FormStateInterface $form_state){
    $form_state->setRedirect('vrt_dram.batch', array());
}

woutersf

<?php
use Drupal\image\Entity\ImageStyle;
use \Drupal\file\Entity\File;

//Load the file
$file_id = 2;
$file = file_load($file_id);

//Render the IMage style "large"
$image_large_url = ImageStyle::load('large')->buildUrl($file->getFileUri());

woutersf

<?php
$client = \Drupal::httpClient();
$url = 'http://something.com/data.json';
try {
  $request = $client->get($url);
  $status = $request->getStatusCode();
  //Do something here.
  //For example:
  return json_decode($request->getBody()->getContents());
}

woutersf

<?php
// Fetching The data via the container (old variable_get)
$data = \Drupal::config('my_module.settings')->get('my_setting_name');

// Fetching the data via the Settings class
use Drupal\Core\Site\Settings;

$settings = Settings::get('http_client_config');
$data = $settings['my_setting_name'];

woutersf

<?php

// Drupal 7
global $is_https;
if ($is_https) {
  // Do something
}

// Drupal 8
if (Drupal::request()->isSecure()) {