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https://github.com/tag1consulting/d7_to_d10_migration.git
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61 lines
2.6 KiB
JavaScript
61 lines
2.6 KiB
JavaScript
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(function ($) {
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/**
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* Prevents consecutive form submissions of identical form values.
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*
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* Repetitive form submissions that would submit the identical form values are
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* prevented, unless the form values are different from the previously
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* submitted values.
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*
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* This is a simplified re-implementation of a user-agent behavior that should
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* be natively supported by major web browsers, but at this time, only Firefox
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* has a built-in protection.
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*
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* A form value-based approach ensures that the constraint is triggered for
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* consecutive, identical form submissions only. Compared to that, a form
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* button-based approach would (1) rely on [visible] buttons to exist where
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* technically not required and (2) require more complex state management if
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* there are multiple buttons in a form.
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*
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* This implementation is based on form-level submit events only and relies on
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* jQuery's serialize() method to determine submitted form values. As such, the
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* following limitations exist:
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*
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* - Event handlers on form buttons that preventDefault() do not receive a
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* double-submit protection. That is deemed to be fine, since such button
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* events typically trigger reversible client-side or server-side operations
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* that are local to the context of a form only.
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* - Changed values in advanced form controls, such as file inputs, are not part
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* of the form values being compared between consecutive form submits (due to
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* limitations of jQuery.serialize()). That is deemed to be acceptable,
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* because if the user forgot to attach a file, then the size of HTTP payload
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* will most likely be small enough to be fully passed to the server endpoint
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* within (milli)seconds. If a user mistakenly attached a wrong file and is
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* technically versed enough to cancel the form submission (and HTTP payload)
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* in order to attach a different file, then that edge-case is not supported
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* here.
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*
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* Lastly, all forms submitted via HTTP GET are idempotent by definition of HTTP
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* standards, so excluded in this implementation.
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*/
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Drupal.behaviors.formSingleSubmit = {
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attach: function () {
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function onFormSubmit (e) {
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var $form = $(e.currentTarget);
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var formValues = $form.serialize();
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var previousValues = $form.attr('data-drupal-form-submit-last');
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if (previousValues === formValues) {
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e.preventDefault();
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}
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else {
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$form.attr('data-drupal-form-submit-last', formValues);
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}
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}
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$('body').once('form-single-submit')
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.delegate('form:not([method~="GET"])', 'submit.singleSubmit', onFormSubmit);
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}
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};
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})(jQuery);
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