How can I add a new value for a multi-value field programmatically?

Question

If there is a unlimited user text field named "user_log_field", How can I add a new value for it?

I'm planning to log the IP and location for each user every time they login. Is using an unlimited user text field a good idea for this purpose?

Answer 1

Architectually speaking, it would be much better if you use custom table for this functionality.You can take a look for inspiration (or even use) the following module:

https://www.drupal.org/project/uiplog

From the description of the project: User IP Log is a simple module that logs the IP address of users on login event to table {uiplog}.

Updated answer: Since you want to do it yourself. You can implement a hook_user_login in your custom module. https://api.drupal.org/api/drupal/core%21modules%21user%21user.api.php/function/hook_user_login/8.2.x

Inside you can just paste the following code.

Assumptions/ notes :

• This is simple text field is from the type: "Text (plain)". If you choose any other option I am not sure if this snippet would work for you.
• The machine name of the field is field_field_1. Not the best name but you could quite easily change that on line 5.

I have added quite a few sanity checks that I think would be helpful on the long run.

// Load the current user.
$user = \Drupal\user\Entity\User::load(\Drupal::currentUser()->id());

// The machine name of the field.
$field_name = 'field_field_1';
// Sanity check against the machine name of the field.
if ($user->hasField($field_name)) {
  $field_config = \Drupal\field\Entity\FieldStorageConfig::loadByName('user', $field_name);
  // Checks if has unlimited cardinality, otherwise the appendItem will throw
  // weird error.
  if ($field_config->getCardinality() == '-1') {
    // This is a fancy way to return $_SERVER['REMOTE_ADDR'].
    // Keep in mind that on localhost, this will return ::1.
    $a = \Drupal::request()->getClientIp();
    $user->$field_name->appendItem(\Drupal::request()->getClientIp());
  }
  $user->save();
}

Regards,

Oleg

Answer 2

An unlimited user text field would be best in my opinion. The way I would implement it would be to write a hook to alter the user login form. In this hook you would assign an IP address to your user field and save it.

Edit: This is the best option, in the absence of a module wich already provides this functionality. If a module already exists, use it.