form

In this post we’ll see how to save temporarily values from a form and how to retrieve or process them later in a controller. To do that, we’ll use the Form API and the private tempstore (the temporary store storage system of Drupal 8).

Creating forms is part of the day to day live of a Drupal programmer.  Forms are represented as nested arrays in both Drupal 7 and Drupal 8. But they are different in that in Drupal 7 you define your form arrays in functions and in Drupal 8 you create a form class.

In this post we’ll create a custom form with two fields, a text field and a checkbox field, we’ll validate those fields, display them in a message and finally redirect the user to the home page.

You can find the code of this module here.

Here is a screenshot of the form:

In Drupal 7, to manage system variables, we used variable_get() / variable_set() /  variable_del() calls and stored those variables in the variable table of the database.

In Drupal 8 we now use the Configuration system which provides a central place for modules to store configuration data. This system allows to store information that can be synchronized between development and production sites. This information is often created during site building and is not typically generated by regular users during normal site operation.
In Drupal 8 configuration is still stored in the database,  but it can now be synced with YML files on the disk for deployment purposes aswell.