Add Plugin Integration for Mailchimp

[zutigrm]

Feature Description

Mailchimp conversion events should be supported in the new conversion event tracking infrastructure.

See implementation and class design and plugin specific notes section in the design doc

---

Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• Conversion events from Mailchimp should be tracked and supported by our infrastructure.
• When Mailchimp form is submitted, a conversion event - submit_lead_form should be tracked.

Implementation Brief

• Add Google\Site_Kit\Core\Conversion_Tracking\Conversion_Event_Providers\Mailchimp
  • It should implement Google\Site_Kit\Core\Conversion_Tracking\Conversion_Events_Provider interface.
  • Define class property conversion_provider_slug with a value, say mailchimp
  • It should have following methods:
    • is_active - check if MC4WP_VERSION constant is defined
      • return true if it is
      • otherwise return false
    • get_event_names - return an associative array contain one string submit_lead_form
    • register_script - Instantiate the Google\Site_Kit\Core\Assets\Script class and register the script, leveraging the execution argument for deferring the script. It should return the Script instance.
      • You can see an example of instantiating the Script class here

        site-kit-wp/includes/Core/Assets/Assets.php

        Lines 441 to 449 in fd7efe4

        	new Script(
        	'googlesitekit-polyfills',
        	array(
        	'src' => $base_url . 'js/googlesitekit-polyfills.js',
        	'dependencies' => array(
        	'googlesitekit-base-data',
        	),
        	)
        	),

      • Use mc4wp-forms-api script as dependency
      • Include 'execution' => 'defer'
      • For handle name use gsk-cep-{$this->conversion_provider_slug}
      • return the Script instance
• Add assets/js/event-providers/mailchimp.js
  • Include the Mailchimp specific event listener that will trigger the event once document is loaded. Mailchimp uses custom event handling, so this is the way to attach event listener:

mc4wp.forms.on('subscribed', function(form) {
  // gtag.js
  gtag('event', 'submit_lead_form', {'event_category': 'Mailchimp', 'event_label': 'Name: ' + form.name + ' ID: ' + form.id});
});

• Include JS file path in the conversionEventProviders.config.js webpack partial added in Add Webpack Partial That Will Build Conversion Providers Specific JS Files #8531
• Ensure yield conversionEventProviders( mode ); is run in the main webpack.config.js config (it is commented out while there are no entry points)
• Include the plugin name and class path to the array of main Conversion_Events class property added in Add Main Conversion_Tracking Class #8528

Test Coverage

• You can add basic test coverage for Mailchimp class, testing that get_event_names method returns correct event names, and register_script returns script instance with proper handle. Also is_active method can be confirmed by defining the plugin constant

QA Brief

Changelog entry

[eugene-manuilov]

@zutigrm, similarly to the CF7 integration, we need to specify exact events that we expect to be triggered after this integration is implemented.

[eugene-manuilov]

AC ✔️

[eugene-manuilov]

IB ✔️