Drupal Interview Questions and Answers

It is a very useful tool as it helps you perform various admin tasks using one or two commands in the terminal, replacing the need for many clicks and page refreshes in the UI. "DRUSH" is an awesome shell interface for managing Drupal right from our cloud server using command line.

Drupal consists of multiple layers for execution. Hence, caching is a vital aspect of Drupal to measure performance accurately.

Here are the various ways of caching in Drupal:

• DRUPAL INTERNAL CACHING
• CUSTOM CACHE USING DRUPAL’S CACHE API
• DRUPAL VIEWS CACHE:
• MEMCACHE
• OPCODE CACHE
• REVERSE PROXY - VARNISH
• BOOST Caching
• Using Content Delivery Networks(CDN)

It is a piece of individual content such as a page, poll and article. Most content on a Drupal website is stored/treated as "nodes".

To install JQuery in Drupal, follow these steps carefully:

• Start with downloading the jquery_ui Drupal module by using the stable version available (6.x-1.5). Now, move it to your modules folder (e.g. sites/all/modules/jquery_ui)
• Now, go to the jQuery UI and then download the "Legacy" 1.7.x version. Not the 1.8.x version or any other later branch!
• After completing the above step, inside a temporary directory, extract the directory "development-bundle" collected from the archive and finally rename it to "jquery.ui".
• After renaming, start copying the renamed directory, (jquery.ui) into the sites/all/libraries folder (create a separate folder like this if it should look like sites/all/libraries/jquery.ui.)
• Finally activate the jquery_ui module in Drupal version 8.

While there are many methods to enable Twig Debug, this is one of the easiest and simple way

• Step 1: Navigate to the \sites\default in the Drupal 8 dashboard.
• Step 2: Now, start the process by making a copy of the default.services.yml file and renaming it to services.yml (if services.yml does not already exist).
• Step 3: Next, open the file and search for this phrase 'twig.config'.
• Step 4: Once you’ve got the phrase, set the debug mode to true, auto_reload mode to true and cache to false mode.
• Step 5: Finally, go to the bottom of the file and copy the following code block as it is:

Parameters

twig.config:
debug: true

To create a theme in Drupal 8 from scratch, use the following steps:

• Create a theme folder inside Drupal 8 to store your theme in a .info.yml file and libraries file.
• Create the .info.yml file
• Create the .libraries.yml file.
• Start creating the stylesheets
• Now, create designs and then, you have your own theme in Drupal 8.

• New Theme Engine : It includes a brand new theming engine called Twig. It is PHP-based, flexible, fast, and secure.
• Drupal 8 is mobile first now
• It has extensive multilingual features right out of the box.
• It has configuration management built into it at the file-system level so that carrying over configuration elements in Drupal 8.
• Easy Authoring : It bring unprecedented power into the hands of the Content Editor, with WYSIWYG editor CKEditor now bundled with the core.
• Views Now Part of its Core :
• Better Support for Accessibility
• Web Services in-Built in Drupal 8
• In Drupal 8 it has Guided Tour
• JavaScript Automated Testing in Drupal 8
• Loading Speed improvement in Drupal 8.

Adding regions to a theme requires two things that's are given below :-

• Adding region meta-data to your THEMENAME.info.yml file.
• Please edit your page.html.twig file then print new regions.

Default Regions

• page.header
• page.primary_menu
• page.secondary_menu
• page.highlighted
• page.help (It has dynamic help text for admin pages)
• page.content (main content of current page)
• page.sidebar_first
• page.sidebar_second
• page.footer
• page.breadcrumb

It is a powerful core module, gives our sites use of the organizational keywords known in another systems as categories or tags, or metadata. Taxonomy allows you to connect, relate and classify your website's content. These terms are gathered within "vocabularies". It is the practice of classifying content.

It allows you to override a theme function. It is available in the theme directory.

Singleton Design pattern

Drupal does not allow adding PHP code directly inside a post or in a block by default.
To do this, we need to activate a drupal module called PHP filter via Administer Site building Modules.

Solr Search module

Here is a code to insert data from the form to the table in a database in Drupal 8

Example

                                                    
public function submitForm(array &$form, FormStateInterface $form_state) {

$field = $form_state->getValues();

$name = $field['name'];

$email = $field['email'];

$field_arr = [

   'name' => $name,

   'email' => $email

];

$query = \Drupal::database();

$query->insert('users')

   ->fields($field_arr)

   ->execute();

drupal_set_message("data successfully saved");

} 
                                                

To successfully enable a REST API tab in Drupal 8, follow these steps:

• Download and install the REST UI contributed module.
• Now, expose the view data as rest export using Rest UI
• Now, create a CSRF token for completing basic authentication procedures.
• Now, submit files to the node using the REST API

In Drupal 7, custom user profiles are like fieldable entities similar to nodes. To create a new custom user profile, follow these steps:

• First, go the Administration
• Then, go to the Configuration tab
• Next, click on People
• Go to Account settings and add a new field
• Configure the corresponding display to each user page on the Account Settings (ie. /user/$uid).

To disable comments in Drupal 8, there are two parts.

Using Drupal Admin

• First of all, login to your Drupal admin area
• Now, go to the Administrator tab, then Content tab and finally click on the Content Types.
• Now, click and edit the content type you prefer to disable the comments for.
• Lastly, you must ensure the comments are on ‘OFF’ mode by default

If you’re using Drupal 7.x/8.x use the following method to disable the comments:

• Login to your admin area
• Go to Structure -> Content -> Types ->Comment Settings
• Select the option 'Closed' present under 'Default comment setting'
• Save the changes

By executing an SQL query

Deleting/disabling the comments can also be executed by the SQL query in the phpMyAdmin. Here are the steps to follow:

Execute this SQL query in your database

UPDATE system SET status = ‘0’ WHERE filename = ‘modules/comment/comment.module’;

If you would like to reverse the effect, i.e. enable comments at a later stage, simply change the SET status = ‘1’

Detailed system requirements for a Drupal 8 installation.

• Websites built in Drupal 8 core are compatible with, and fully functional in, all latest browsers support CSS and JavaScript.
• Database server to run Drupal 8
• Drupal 8 works on web servers with PHP 5.5.9 or greater.
• Detailed information regarding the PHP requirements for Drupal 8.
• 32-bit PHP can only support a limited range of dates.

For more detail you can visit its official website : Click here

It is a Content Management Framework, from which we can build a CMS tailored specifically for our needs.

It is an acronym for PHP Data Objects. It is a lean, consistent way to access databases. PDO is just like a data access layer which uses a unified API.

To enable PDO, configure --enable-pdo and --with-pdo-sqlite --with-pdo-mysql or whatever database needs supporting by PDO

For windows users : For Apache, you will need to make sure php_pdo.dll and php_pdo_mysql.dll exist in the php/ext directory, un-comment or add the appropriate lines in php.ini, after that you have to restart the web server. In windows it may no longer be required to enable PDO when using newer versions of PHP, PHP version 5.3 and later. It refers to php_pdo.dll. However, you still need to activate php_pdo_mysql.dll for MySQL or for whichever database you are using.

A Module is a collection of files which containing some functionality and is written in PHP because the module code executes within the context of the site.

In Drupal some of the modules recommended here :-

• Views
• Token
• Ctools
• Quicktabs
• Pathauto
• Webform
• Google Analytics etc

Some of the SEO modules available in Drupal that's are given below:-

• Pathauto
• Meta tags/ Node words
• Service Links
• Google Analytics
• Related Links
• Search 404
• Site map
• Url list

Drupal supports MySQL, MariaDB, PostgreSQL and SQLite.

CTools or Chaos Tool Suite in Drupal is a project-oriented towards better coding for developers. It is basically a set of tutorial classes that have been simplified to explain certain workflows meanwhile also defining some custom functionalities.