Add example for overriding data source

Author: jtsternberg

filters-and-actions/override-cmb2-data-source.php

@@ -0,0 +1,97 @@
+<?php
+/**
+ * Demonstrates using an alternate data source for storing/retrieving data for a CMB2 box.
+ * In this case, we're simply storing/retrieving/removing from an option in the options table,
+ * but this can be extended to handle data storage to/from custom tables, Redis, REST APIs, etc.
+ */
+
+add_action( 'cmb2_init', 'yourprefix_register_yourprefix_group_alt_data_metabox' );
+/**
+ * Hook in and add a metabox to demonstrate repeatable grouped fields
+ */
+function yourprefix_register_yourprefix_group_alt_data_metabox() {
+
+$default_values = get_option( 'yourprefix_group_alt_data_demo' );
+if ( ! is_array( $default_values ) ) {
+add_option( 'yourprefix_group_alt_data_demo', array(
+// Default group 1.
+array(
+'title' => 'Hey, this is your first entry',
+'description' => 'Go ahead and delete this entry, or update its contents',
+),
+// Default group 2.
+array(
+'title' => 'Hey, this is your 2nd entry',
+'description' => '#2',
+),
+) );
+}
+
+$cmb_group = new_cmb2_box( array(
+'id' => 'yourprefix_group_alt_data_metabox',
+'title' => __( 'Repeating Field Group', 'cmb2' ),
+'object_types' => array( 'post', ),
+'show_on' => array( 'id' => array( 1000, ) ),
+'show_in_rest' => WP_REST_Server::ALLMETHODS,
+) );
+
+// $group_field_id is the field id string, so in this case: '_yourprefix_group_demo'
+$group_field_id = $cmb_group->add_field( array(
+'id' => 'yourprefix_group_alt_data_demo',
+'type' => 'group',
+'options' => array(
+'group_title' => __( 'Entry {#}', 'cmb2' ), // {#} gets replaced by row number
+'add_button' => __( 'Add Another Entry', 'cmb2' ),
+'remove_button' => __( 'Remove Entry', 'cmb2' ),
+'sortable' => true, // beta
+),
+) );
+
+/**
+ * Group fields works the same, except ids only need
+ * to be unique to the group. Prefix is not needed.
+ *
+ * The parent field's id needs to be passed as the second argument.
+ */
+$cmb_group->add_group_field( $group_field_id, array(
+'name' => 'Entry Title',
+'id' => 'title',
+'type' => 'text',
+) );
+
+$cmb_group->add_group_field( $group_field_id, array(
+'name' => 'Description',
+'description' => 'Write a short description for this entry',
+'id' => 'description',
+'type' => 'wysiwyg',
+'options' => array(
+'textarea_rows' => 3,
+),
+) );
+};
+
+add_filter( 'cmb2_override_yourprefix_group_alt_data_demo_meta_value', 'yourprefix_group_alt_data_demo_override_meta_value', 10, 4 );
+function yourprefix_group_alt_data_demo_override_meta_value( $data, $object_id, $args, $field ) {
+
+// Here, we're pulling from the options table, but you can query from any data source here.
+// If from a custom table, you can use the $object_id to query against.
+return get_option( 'yourprefix_group_alt_data_demo', array() );
+}
+
+add_filter( 'cmb2_override_yourprefix_group_alt_data_demo_meta_save', 'yourprefix_group_alt_data_demo_override_meta_save', 10, 4 );
+function yourprefix_group_alt_data_demo_override_meta_save( $override, $args, $field_args, $field ) {
+
+// Here, we're storing the data to the options table, but you can store to any data source here.
+// If to a custom table, you can use the $args['id'] as the reference id.
+$updated = update_option( 'yourprefix_group_alt_data_demo', $args['value'] );
+return !! $updated;
+}
+
+add_filter( 'cmb2_override_yourprefix_group_alt_data_demo_meta_remove', 'yourprefix_group_alt_data_demo_override_meta_remove', 10, 4 );
+function yourprefix_group_alt_data_demo_override_meta_remove( $override, $args, $field_args, $field ) {
+// Here, we're removing from the options table, but you can query to remove from any data source here.
+// If from a custom table, you can use the $args['id'] to query against.
+// (If we do "delete_option", then our default value will be re-applied, which isn't desired.)
+$updated = update_option( 'yourprefix_group_alt_data_demo', array() );
+return !! $updated;
+}