Merge pull request #655 from carstingaxion/feature/export-import

Export & Import

includes/core/classes/class-export.php

@@ -0,0 +1,212 @@
+<?php
+/**
+ * Class responsible for exporting content using WordPress' native export tool.
+ *
+ * @package GatherPress\Core
+ * @since 1.0.0
+ */
+
+namespace GatherPress\Core;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use GatherPress\Core\Traits\Singleton;
+use WP_Post;
+
+/**
+ * Class Export.
+ *
+ * The Export class handles the exporting of content using WordPress' native export tool.
+ * This class will enhance overall export management, provide effective filtering
+ * and support validation of the export-objects based on their post type and meta data.
+ *
+ * @since 1.0.0
+ */
+class Export extends Migrate {
+	/**
+	 * Enforces a single instance of this class.
+	 */
+	use Singleton;
+
+	/**
+	 * The post_meta name for GatherPress temporary entry,
+	 * to hook into WordPress export.
+	 *
+	 * @since 1.0.0
+	 * @var string $POST_META
+	 */
+	const POST_META = 'gatherpress_extend_export';
+
+	/**
+	 * Class constructor.
+	 *
+	 * This method initializes the object and sets up necessary hooks.
+	 *
+	 * @since 1.0.0
+	 */
+	public function __construct() {
+		$this->setup_hooks();
+	}
+
+	/**
+	 * Set up hooks for various purposes.
+	 *
+	 * This method adds hooks for different purposes as needed.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	protected function setup_hooks(): void {
+		/**
+		 * Fires at the beginning of an export, before any headers are sent.
+		 */
+		add_action( 'export_wp', array( $this, 'export' ) );
+	}
+
+	/**
+	 * Sets up the necessary hooks for the export process.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	public function export(): void {
+		add_action( 'the_post', array( $this, 'prepare' ), 10, 2 );
+		add_filter( 'wxr_export_skip_postmeta', array( $this, 'extend' ), 10, 3 );
+	}
+
+	/**
+	 * Saves a temporary marker as postmeta,
+	 * which allows to hook into the export process per post later on.
+	 *
+	 * Called via setup_postdata() at the beginning of each singular post export.
+	 *
+	 * Fires once the post data has been set up.
+	 *
+	 * @param  WP_Post $post  The Post object (passed by reference).
+	 * @return void
+	 */
+	public function prepare( WP_Post $post ): void {
+		if ( $this->validate( $post ) ) {
+			add_post_meta( $post->ID, self::POST_META, true );
+		}
+	}
+
+	/**
+	 * Extend WordPress' native Export
+	 *
+	 * WordPress' native Export can be extended in hacky way using `wxr_export_skip_postmeta`
+	 * where GatherPress echos out some pseudo-post-meta fields,
+	 * before returning `false` like the default.
+	 *
+	 * @source https://github.com/WordPress/wordpress-develop/blob/6.5/src/wp-admin/includes/export.php#L655-L677
+	 *
+	 * Normally this filters whether to selectively skip post meta used for WXR exports.
+	 * Returning a truthy value from the filter will skip the current meta object from being exported.
+	 *
+	 * @see https://developer.wordpress.org/reference/hooks/wxr_export_skip_postmeta/
+	 *
+	 * But because there is no 'do_action('per-exported-post)',
+	 * GatherPress created a post_meta entry as a temporary marker, to be used as an entry-point into
+	 * WordPress' native export process, which is used now.
+	 *
+	 * @param  bool   $skip     Whether to skip the current post meta. Default false.
+	 * @param  string $meta_key Current meta key.
+	 * @param  object $meta     Current meta object.
+	 * @return bool             Whether to skip the current post meta. Default false.
+	 */
+	public function extend( bool $skip, string $meta_key, object $meta ): bool {
+		if ( self::POST_META === $meta_key ) {
+			// Echos out xml with pseudo-postmeta.
+			$this->run( get_post( $meta->post_id ) );
+
+			// Deletes temporary marker.
+			delete_post_meta( $meta->post_id, self::POST_META );
+
+			// Prevent 'normal' export processing for that particular postmeta field,
+			// because it doesn't exist in real and will trigger an error.
+			return true;
+		}
+
+		return $skip;
+	}
+
+	/**
+	 * Checks if the currently exported post is of type 'gatherpress_event'.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param  WP_Post $post Current meta key.
+	 * @return bool          True, when the currently exported post is of type 'gatherpress_event', false otherwise.
+	 */
+	protected function validate( WP_Post $post ): bool {
+		return ( Event::POST_TYPE === $post->post_type );
+	}
+
+	/**
+	 * Exports all custom data.
+	 *
+	 * Gets all 'pseudopostmetas' and generates WXR-compatible output for each,
+	 * the generated xml markup is rendered into the WordPress export file directly.
+	 *
+	 * An export file like this can be imported into GatherPress using
+	 * the native 'WordPress importer' and its potential replacement the 'WordPress importer (v2)'.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param  WP_Post $post Current 'gatherpress_event' post being exported.
+	 * @return void
+	 */
+	public function run( WP_Post $post ): void {
+		$pseudopostmetas = $this->get_pseudopostmetas();
+
+		array_walk(
+			$pseudopostmetas,
+			array( $this, 'render' ),
+			$post
+		);
+	}
+
+	/**
+	 * Render custom post_meta data into xml markup to be used while WordÜress' native export.
+	 *
+	 * @param  array   $callbacks Associative array with (import & export) callback functions for a the non-existent post_meta entry, named by $key.
+	 * @param  string  $key       Name of the custom post_meta, that should be exported.
+	 * @param  WP_Post $post      The currently exported 'gatherpress_event' post.
+	 * @return void
+	 */
+	public function render( array $callbacks, string $key, WP_Post $post ) {
+		if ( ! isset( $callbacks['export_callback'] ) || ! is_callable( $callbacks['export_callback'] ) ) {
+			return;
+		}
+
+		$value = call_user_func( $callbacks['export_callback'], $post );
+
+		?>
+		<wp:postmeta>
+			<wp:meta_key><?php echo wxr_cdata( $key ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?></wp:meta_key>
+			<wp:meta_value><?php echo wxr_cdata( $value ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?></wp:meta_value>
+		</wp:postmeta>
+		<?php
+	}
+
+	/**
+	 * Returns dates, times and timezone from the 'wp_gatherpress_events' DB table
+	 * as serialized string for the current post being exported.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @param  WP_Post $post Current 'gatherpress_event' post being exported.
+	 * @return string        Serialized JSON string with all date, time & timezone data of the current $post.
+	 */
+	public function datetimes_callback( WP_Post $post ): string {
+		// Make sure to not get any user-related data.
+		remove_all_filters( 'gatherpress_timezone' );
+
+		$event = new Event( $post->ID );
+
+		return maybe_serialize( $event->get_datetime() );
+	}
+}

includes/core/classes/class-import.php

@@ -0,0 +1,184 @@
+<?php
+/**
+ * Class responsible for importing content using WordPress' native import tool(s).
+ *
+ * @package GatherPress\Core
+ * @since 1.0.0
+ */
+
+namespace GatherPress\Core;
+
+// Exit if accessed directly.
+defined( 'ABSPATH' ) || exit; // @codeCoverageIgnore
+
+use GatherPress\Core\Event;
+use GatherPress\Core\Migrate;
+use GatherPress\Core\Traits\Singleton;
+use WP_Post;
+
+/**
+ * Class Import.
+ *
+ * The Import class handles the importing of content using WordPress' native import tool.
+ * This class will provide effective filtering and support validation of the import-objects
+ * based on their post type and meta data.
+ *
+ * Succesfully identified GatherPress data will be saved into custom DB tables.
+ *
+ * @since 1.0.0
+ */
+class Import extends Migrate {
+	/**
+	 * Enforces a single instance of this class.
+	 */
+	use Singleton;
+
+	/**
+	 * Class constructor.
+	 *
+	 * This method initializes the object and sets up necessary hooks.
+	 *
+	 * @since 1.0.0
+	 */
+	public function __construct() {
+		$this->setup_hooks();
+	}
+
+	/**
+	 * Set up hooks for various purposes.
+	 *
+	 * This method adds hooks for different purposes as needed.
+	 *
+	 * @since 1.0.0
+	 *
+	 * @return void
+	 */
+	protected function setup_hooks(): void {
+		if ( class_exists( 'WXR_Importer' ) ) {
+			/**
+			 * Setup for WordPress Importer (v2).
+			 *
+			 * @see https://github.com/humanmade/Wordpress-Importer
+			 */
+			$hook_name = 'wxr_importer.pre_process.post';
+		} else {
+			/**
+			 * Setup for default WordPress Importer.
+			 *
+			 * @see https://github.com/WordPress/wordpress-importer/issues/42
+			 */
+			$hook_name = 'wp_import_post_data_raw';
+		}
+
+		add_filter( $hook_name, array( $this, 'prepare' ) );
+		add_action( 'gatherpress_import', array( $this, 'extend' ) );
+	}
+
+	/**
+	 * Extend WordPress' native Import.
+	 *
+	 * @see https://github.com/WordPress/wordpress-importer/blob/71bdd41a2aa2c6a0967995ee48021037b39a1097/src/class-wp-import.php#L631
+	 *
+	 * @param  array $post_data_raw The result of 'wp_import_post_data_raw'.
+	 * @return array                Returns the unchanged result of 'wp_import_post_data_raw'.
+	 */
+	public function prepare( array $post_data_raw ): array {
+		if ( $this->validate( $post_data_raw ) ) {
+			/**
+			 * Fires for every GatherPress data to be imported.
+			 *
+			 * @since 1.0.0
+			 *
+			 * @param {array} $post_data_raw Unprocessesd 'gatherpress_event' post being imported.
+			 */
+			do_action( 'gatherpress_import', $post_data_raw );
+		}
+
+		return $post_data_raw;
+	}
+
+	/**
+	 * Checks if the currently imported post is of type 'gatherpress_event'.
+	 *
+	 * @param  array $post_data_raw The result of 'wp_import_post_data_raw'.
+	 * @return bool                 True, when the currently imported post is of type 'gatherpress_event', false otherwise.
+	 */
+	protected function validate( array $post_data_raw ): bool {
+		return ( isset( $post_data_raw['post_type'] ) && Event::POST_TYPE === $post_data_raw['post_type'] );
+	}
+
+	/**
+	 * Import all custom data.
+	 *
+	 * @return void
+	 */
+	public function extend(): void {
+		add_filter( 'add_post_metadata', array( $this, 'run' ), 10, 5 );
+	}
+
+	/**
+	 * Import data with custom scheme.
+	 *
+	 * This method is called on every imported post_meta
+	 * and allows to work with the data to be imported.
+	 *
+	 * It checks if the current meta_key is one of GatherPress' pseudopostmetas
+	 * and if an import-callback for that key exists.
+	 * If both is true, the import callback is provided with all available information and called once per meta_key.
+	 *
+	 * The normal saving into the 'wp_postmeta' DB table is disabled in such a case.
+	 *
+	 * @see https://developer.wordpress.org/reference/hooks/add_meta_type_metadata/
+	 * @see https://www.ibenic.com/hook-wordpress-metadata/
+	 *
+	 * @param  null|bool $check      Whether to allow adding metadata for the given type.
+	 * @param  int       $object_id  ID of the object metadata is for.
+	 * @param  string    $meta_key   Metadata key.
+	 * @param  mixed     $meta_value Metadata value. Must be serializable if non-scalar.
+	 * @param  bool      $unique     Whether the specified meta key should be unique for the object.
+	 * @return null|bool             Returning a non-null value will effectively short-circuit the saving of 'normal' meta data.
+	 */
+	public function run( ?bool $check, int $object_id, string $meta_key, $meta_value, bool $unique ): ?bool {
+		$pseudopostmetas = $this->get_pseudopostmetas();
+
+		if ( ! isset( $pseudopostmetas[ $meta_key ] ) ) {
+			return null;
+		}
+
+		if (
+			! isset( $pseudopostmetas[ $meta_key ]['import_callback'] ) ||
+			! is_callable( $pseudopostmetas[ $meta_key ]['import_callback'] )
+		) {
+			return null;
+		}
+
+		/*
+		 * Run import callback,
+		 * e.g. Save data into a custom DB table.
+		 */
+		call_user_func(
+			$pseudopostmetas[ $meta_key ]['import_callback'],
+			$object_id,
+			$meta_value
+		);
+
+		/*
+		 * Disable saving of 'normal' meta data.
+		 */
+		return false;
+	}
+
+
+	/**
+	 * Save dates, times & timezone for the currently imported 'gatherpress_event' post.
+	 *
+	 * @param  int   $post_id   ID of the object metadata is for.
+	 * @param  mixed $data      Metadata value. Must be serializable if non-scalar.
+	 * @return void
+	 */
+	public function datetimes_callback( int $post_id, $data ): void {
+		$event = new Event( $post_id );
+
+		$event->save_datetimes( maybe_unserialize( $data ) );
+	}
+}