How do I allow date-time filtering on my custom entity's ISO date field

Question

I have a custom entity with a datetime field. This datetime is saved in the database as an ISO string. I would like to use Views on this entity, and select entities with dates before, after, or between certain dates. I see if I make a view against the system log, these options are presented when filtering on Timestamp. How can I enable the same filtering options on my field?

The field definition is:

$fields['set_datetime'] = BaseFieldDefinition::create('datetime')
  ->setLabel(t('Set DateTime'))
  ->setDescription(t('Date and time fermentor was set.'))
  ->setSettings(array(
    'datetime_type' => 'datetime',
  ))
  ->setDefaultValue('')
  ->setDisplayOptions('view', array(
    'label' => 'above',
    'type' => 'string',
    'weight' => -4,
  ))
  ->setDisplayOptions('form', array(
    'weight' => -4,
  ))
  ->setDisplayConfigurable('form', TRUE)
  ->setDisplayConfigurable('view', TRUE);

Answer 1

I posted the following as a bug report to Drupal Core

When a custom entity is created, and one of the fields is a datetime FieldType, views filters are not treating this field like a datetime field, but, instead, like a string. Timestamp Fieldtypes on the other hand are presented with the correct filter options.

The response I received was:

Yes, it does default to a string. I think the underlying reason is this:

Datetime support comes from the datetime module, so if you want your entity to use that, add a dependency to datetime and override any defaults for your entity in an extension of \Drupal\views\EntityViewsData.

The Views 'date' filter only works for timestamps (hence your timestamp fields work out-of-the-box), so just setting the filter plugin_id to 'date' won't help either.

So this works as designed I think.

Answer 2

After checking your module provided for me on github and some reverse-engineering I find out the problem is on create('datetime') and you should use create('created') So the following code

$fields['date'] = BaseFieldDefinition::create('created')
  ->setLabel(t('DateTime'))
  ->setDescription(t('Date and time.'))
  ->setDisplayOptions('view', array(
    'label' => 'above',
    'type' => 'timestamp',
    'weight' => -4,
  ))
  ->setDisplayOptions('form', array(
    'type' => 'datetime_timestamp',
    'weight' => -4,
  ))
  ->setDisplayConfigurable('form', TRUE)
  ->setDisplayConfigurable('view', TRUE);

Results the below image for me. it seems it's Ok now.