WordPress function to get raw widget data for all of the widgets in a given sidebar

rh-get-widget-data-for-all-sidebars.php

<?php
function rh_get_widget_data_for_all_sidebars() {
	global $wp_registered_sidebars;

	$output = array();
	foreach ( $wp_registered_sidebars as $sidebar ) {
		if ( empty( $sidebar['name'] ) ) {
			continue;
		}
		$sidebar_name = $sidebar['name'];
		$output[ $sidebar_name ] = rh_get_widget_data_for( $sidebar_name );
	}
	return $output;
}

rh-get-widget-data-for.php

<?php
function rh_get_widget_data_for( $sidebar_name ) {
	global $wp_registered_sidebars, $wp_registered_widgets;

	// Holds the final data to return
	$output = array();

	// Loop over all of the registered sidebars looking for the one with the same name as $sidebar_name
	$sibebar_id = false;
	foreach ( $wp_registered_sidebars as $sidebar ) {
		if ( $sidebar['name'] == $sidebar_name ) {
			// We now have the Sidebar ID, we can stop our loop and continue.
			$sidebar_id = $sidebar['id'];
			break;
		}
	}

	if ( ! $sidebar_id ) {
		// There is no sidebar registered with the name provided.
		return $output;
	}

	// A nested array in the format $sidebar_id => array( 'widget_id-1', 'widget_id-2' ... );
	$sidebars_widgets = wp_get_sidebars_widgets();
	$widget_ids = $sidebars_widgets[ $sidebar_id ];

	if ( ! $widget_ids ) {
		// Without proper widget_ids we can't continue.
		return array();
	}

	// Loop over each widget_id so we can fetch the data out of the wp_options table.
	foreach ( $widget_ids as $id ) {
		// The name of the option in the database is the name of the widget class.
		$option_name = $wp_registered_widgets[ $id ]['callback'][0]->option_name;

		// Widget data is stored as an associative array. To get the right data we need to get the right key which is stored in $wp_registered_widgets
		$key = $wp_registered_widgets[ $id ]['params'][0]['number'];

		$widget_data = get_option( $option_name );

		// Add the widget data on to the end of the output array.
		$output[] = (object) $widget_data[ $key ];
	}

	return $output;
}