The YAML Form module provides plugins and hooks that allow contrib and custom modules to extend and enhance form elements and submission handling.
The YamlFormElement plugin is used to integrate and enhance form elements so that they can be properly integrated into the YAML Form module. For example, to properly validate and handle file uploads using the ‘Managed file’ element, the YAML Form module provides a YamlFormElement plugin called ManagedFile, which saves the uploaded files to a YAML Form specific file directory.
The YamlFormHandler plugin allows developers to extend a form’s submission handling. Each YamlFormHandler plugin should live in a dedicated module and handler namespace. For example, if a developer wanted to setup MailChimp integration, they would create the ‘YAML Form MailChimp’ module (yamlform_mailchimp.module), which would contain the YamlFormMailChimpHandler.
This approach/pattern allows popular YamlFormHandler plugins (that include tests) to be easily contributed back to the main YAML Form module.
See API documentation.
Third Party Settings
The YAML Form module also allows contrib modules to define third party settings for all forms and/or for one specific form.
See the yamlform_test_third_party_settings.module for an example of how a contrib module can use third party settings to extend and enhance the YAML Form module.