CiviCRM internal AJAX path ( q=civicrm/ajax/* ) should set wp_doing_ajax - Gravity Forms 2.5.3+ breaks Mailings
CiviCRM version: 5.37.2
Today ran into an issue on a few client sites where a Gravity Forms update to version 2.5.3+ would cause Mailings to not be loaded.
The cause for this was that a new filter in Gravity Forms would inject a <script> tag immediately after the <head> tag that appears in the body_html JSON field from Mailing.getSingle API calls, with no escaping - which then breaks the JSON parser.
Note that this uses the internal civicrm/ajax path and thus doesn't go through the WP Rest interface.
Gravity Forms checks the DOING_AJAX constant before performing this injection, so the workaround was to add a hook_civicrm_config implementation that would define('DOING_AJAX', true) if the q parameter starts with civicrm/ajax
Would be preferable if this was done something during the initialisation of the CiviCRM WordPress plugin itself, for both admin and front-end paths.
There is a filter wp_doing_ajax, which defaults to DOING_AJAX, however it's worth noting that Gravity Forms does not use the interface to this filter, but the DOING_AJAX constant itself, so in this case it would be better to define DOING_AJAX as well.