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<?php |
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/** |
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* WP-CLI command for generating alt text for images in the media library. |
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* |
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* @package WordPress\AI |
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* |
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* @since 0.9.0 |
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*/ |
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|
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declare( strict_types=1 ); |
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|
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namespace WordPress\AI\CLI; |
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|
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use WP_CLI; |
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use WP_CLI\Utils; |
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use function WordPress\AI\has_valid_ai_credentials; |
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|
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// Exit if accessed directly. |
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defined( 'ABSPATH' ) || exit; |
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|
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/** |
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* Manages AI-powered alt text generation for media library images. |
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* |
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* @since 0.9.0 |
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*/ |
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class Alt_Text_Command { |
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|
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/** |
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* Maximum number of rows shown by the dry-run table. |
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*/ |
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private const DRY_RUN_PREVIEW_LIMIT = 100; |
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|
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/** |
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* Generates alt text for images in the media library using AI. |
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* |
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* Queries images that are missing alt text and generates it using the |
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* ai/alt-text-generation ability. Processes images in batches to manage |
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* memory and API rate limits. |
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* |
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* ## OPTIONS |
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* |
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* [--batch-size=<number>] |
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* : Number of images to process per batch. |
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* --- |
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* default: 20 |
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* --- |
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* |
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* [--dry-run] |
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* : Show what would be processed without making changes. |
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* |
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* [--force] |
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* : Regenerate alt text even for images that already have it. |
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* |
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* [--ids=<ids>] |
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* : Comma-separated list of specific attachment IDs to process. |
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* |
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* [--delay=<milliseconds>] |
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* : Delay in milliseconds between each API call to avoid rate limiting. |
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* --- |
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* default: 500 |
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* --- |
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* |
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* [--yes] |
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* : Skip the confirmation prompt before processing. |
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* |
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* ## EXAMPLES |
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* |
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* # Generate alt text for all images missing it |
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* $ wp ai alt-text generate |
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* |
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* # Dry run to see what would be processed |
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* $ wp ai alt-text generate --dry-run |
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* |
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* # Regenerate alt text for specific images |
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* $ wp ai alt-text generate --ids=42,55,100 --force |
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* |
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* # Process in small batches with custom delay, skipping confirmation |
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* $ wp ai alt-text generate --batch-size=5 --delay=1000 --yes |
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* |
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* @when after_wp_load |
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* |
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* @param array<int, string> $args Positional arguments. |
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* @param array<string, mixed> $assoc_args Associative arguments. |
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*/ |
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public function generate( $args, $assoc_args ): void { |
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$this->ensure_admin_user(); |
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|
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$ability = wp_get_ability( 'ai/alt-text-generation' ); |
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if ( ! $ability ) { |
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WP_CLI::error( 'The ai/alt-text-generation ability is not registered. Make sure the Alt Text Generation experiment is enabled in Settings > AI.' ); |
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return; // WP_CLI::error() exits, but this satisfies static analysis. |
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} |
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|
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if ( ! has_valid_ai_credentials() ) { |
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WP_CLI::error( 'No valid AI credentials found. Configure a provider in Settings > Connectors.' ); |
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return; // WP_CLI::error() exits, but this satisfies static analysis. |
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} |
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|
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$batch_size = max( 1, (int) Utils\get_flag_value( $assoc_args, 'batch-size', 20 ) ); |
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$dry_run = (bool) Utils\get_flag_value( $assoc_args, 'dry-run', false ); |
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$force = (bool) Utils\get_flag_value( $assoc_args, 'force', false ); |
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$delay_ms = (int) Utils\get_flag_value( $assoc_args, 'delay', 500 ); |
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$ids_flag = (string) Utils\get_flag_value( $assoc_args, 'ids', '' ); |
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|
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$explicit_ids = '' !== $ids_flag ? $this->parse_ids_flag( $ids_flag ) : null; |
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$total = null !== $explicit_ids |
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? count( $explicit_ids ) |
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: $this->count_matching_attachments( $force ); |
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|
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if ( 0 === $total ) { |
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WP_CLI::success( 'No images found matching the criteria.' ); |
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return; |
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} |
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|
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WP_CLI::log( sprintf( 'Found %d image(s) to process.', $total ) ); |
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|
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if ( $dry_run ) { |
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$this->display_dry_run( $explicit_ids, $force, $total ); |
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return; |
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} |
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|
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WP_CLI::confirm( |
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sprintf( 'Generate alt text for %d image(s)? This may incur API costs.', $total ), |
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$assoc_args |
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); |
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|
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$stats = $this->process_images( $ability, $explicit_ids, $total, $batch_size, $delay_ms, $force ); |
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$this->print_summary( $stats ); |
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} |
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|
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/** |
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* Ensures a user with admin capabilities is set for the CLI session. |
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*/ |
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private function ensure_admin_user(): void { |
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if ( 0 !== get_current_user_id() ) { |
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return; |
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} |
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|
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$admins = get_users( |
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array( |
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'role' => 'administrator', |
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'number' => 1, |
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'fields' => 'ID', |
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) |
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); |
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|
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if ( empty( $admins ) ) { |
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WP_CLI::error( 'No administrator user found. Create one or pass --user=<id>.' ); |
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} |
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|
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$admin_id = (int) $admins[0]; |
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wp_set_current_user( $admin_id ); |
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WP_CLI::log( sprintf( 'No --user supplied; running as administrator #%d.', $admin_id ) ); |
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} |
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|
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/** |
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* Parses the --ids flag into a list of valid image attachment IDs. |
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* |
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* @param string $ids_flag Comma-separated IDs from the --ids flag. |
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* @return int[] Array of attachment IDs that exist and are images. |
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*/ |
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private function parse_ids_flag( string $ids_flag ): array { |
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$ids = array_map( 'absint', explode( ',', $ids_flag ) ); |
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$ids = array_filter( $ids ); |
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|
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return array_values( |
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array_filter( |
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$ids, |
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static function ( int $id ): bool { |
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return get_post( $id ) && wp_attachment_is_image( $id ); |
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} |
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) |
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); |
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} |
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|
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/** |
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* Builds the WP_Query arguments shared by counting and batched fetching. |
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* |
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* @param bool $force Whether to include images that already have alt text. |
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* @return array<string, mixed> |
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*/ |
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private function get_attachment_query_args( bool $force ): array { |
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$query_args = array( |
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'post_type' => 'attachment', |
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'post_mime_type' => 'image', |
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'post_status' => 'inherit', |
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'fields' => 'ids', |
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'orderby' => 'ID', |
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'order' => 'ASC', |
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); |
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|
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if ( ! $force ) { |
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$query_args['meta_query'] = array( // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query |
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'relation' => 'OR', |
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array( |
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'key' => '_wp_attachment_image_alt', |
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'compare' => 'NOT EXISTS', |
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), |
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array( |
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'key' => '_wp_attachment_image_alt', |
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'value' => '', |
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'compare' => '=', |
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), |
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); |
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} |
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|
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return $query_args; |
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} |
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|
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/** |
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* Counts how many attachments would be processed. |
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* |
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* @param bool $force Whether to include images that already have alt text. |
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* @return int Total number of matching attachments. |
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*/ |
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private function count_matching_attachments( bool $force ): int { |
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$query_args = $this->get_attachment_query_args( $force ); |
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$query_args['posts_per_page'] = 1; |
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$query_args['no_found_rows'] = false; |
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|
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$query = new \WP_Query( $query_args ); |
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|
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return (int) $query->found_posts; |
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} |
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|
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/** |
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* Fetches the next batch of attachment IDs, starting after a cursor. |
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* |
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* Pagination is cursor-based on the post ID so progress is stable even |
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* as records are mutated mid-run. |
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* |
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* @param bool $force Whether to include images that already have alt text. |
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* @param int $batch_size Maximum number of IDs to return. |
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* @param int $cursor_id Only return IDs greater than this. 0 to start. |
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* @return int[] Attachment IDs ordered ascending. |
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*/ |
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private function fetch_attachment_batch( bool $force, int $batch_size, int $cursor_id ): array { |
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$query_args = $this->get_attachment_query_args( $force ); |
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$query_args['posts_per_page'] = $batch_size; |
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$query_args['no_found_rows'] = true; |
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|
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$where_filter = null; |
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if ( $cursor_id > 0 ) { |
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$where_filter = static function ( $where ) use ( $cursor_id ) { |
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global $wpdb; |
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return $where . $wpdb->prepare( " AND {$wpdb->posts}.ID > %d", $cursor_id ); |
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}; |
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add_filter( 'posts_where', $where_filter ); |
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} |
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|
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try { |
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$query = new \WP_Query( $query_args ); |
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/** @var int[] $ids */ |
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$ids = $query->posts; |
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} finally { |
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if ( null !== $where_filter ) { |
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remove_filter( 'posts_where', $where_filter ); |
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} |
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} |
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|
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return $ids; |
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} |
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|
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/** |
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* Displays the list of images that would be processed in a dry run. |
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* |
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* @param int[]|null $explicit_ids List of IDs from --ids, or null to query. |
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* @param bool $force Whether the live run would include images with alt text. |
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* @param int $total Total count of matching attachments. |
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*/ |
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private function display_dry_run( ?array $explicit_ids, bool $force, int $total ): void { |
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$preview_limit = self::DRY_RUN_PREVIEW_LIMIT; |
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|
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if ( null !== $explicit_ids ) { |
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$preview = array_slice( $explicit_ids, 0, $preview_limit ); |
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} else { |
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$preview = $this->fetch_attachment_batch( $force, $preview_limit, 0 ); |
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} |
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|
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$items = array(); |
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foreach ( $preview as $id ) { |
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$alt = get_post_meta( $id, '_wp_attachment_image_alt', true ); |
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$items[] = array( |
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'ID' => $id, |
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'Title' => get_the_title( $id ), |
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'Current Alt' => ! empty( $alt ) ? $alt : '(empty)', |
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); |
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} |
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|
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Utils\format_items( 'table', $items, array( 'ID', 'Title', 'Current Alt' ) ); |
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|
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if ( $total > $preview_limit ) { |
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WP_CLI::log( sprintf( '... and %d more.', $total - $preview_limit ) ); |
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} |
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|
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WP_CLI::log( sprintf( "\nDry run complete. %d image(s) would be processed.", $total ) ); |
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} |
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|
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/** |
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* Processes images through the alt text generation ability. |
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* |
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* Iterates in batches without holding the full ID set in memory. For |
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* --ids mode the bounded list is sliced; otherwise the database is |
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* queried one batch at a time using a post-ID cursor. |
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* |
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* @param \WP_Ability $ability The alt text generation ability. |
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* @param int[]|null $explicit_ids List of IDs from --ids, or null to query. |
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* @param int $total Total count to process (drives the progress bar). |
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* @param int $batch_size Number of images per batch. |
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* @param int $delay_ms Delay in milliseconds between API calls. |
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* @param bool $force Whether to regenerate existing alt text. |
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* @return array{generated: int, decorative: int, skipped: int, failed: int} |
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*/ |
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private function process_images( $ability, ?array $explicit_ids, int $total, int $batch_size, int $delay_ms, bool $force ): array { |
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$stats = array( |
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'generated' => 0, |
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'decorative' => 0, |
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'skipped' => 0, |
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'failed' => 0, |
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); |
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|
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$progress = Utils\make_progress_bar( 'Generating alt text', $total ); |
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$cursor = 0; |
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$processed = 0; |
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|
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while ( $processed < $total ) { |
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if ( null !== $explicit_ids ) { |
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$batch = array_slice( $explicit_ids, $processed, $batch_size ); |
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} else { |
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$batch = $this->fetch_attachment_batch( $force, $batch_size, $cursor ); |
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} |
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|
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if ( empty( $batch ) ) { |
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break; |
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} |
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|
| 337 |
foreach ( $batch as $id ) { |
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$id = (int) $id; |
| 339 |
if ( $id > $cursor ) { |
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$cursor = $id; |
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} |
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|
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$current_alt = get_post_meta( $id, '_wp_attachment_image_alt', true ); |
| 344 |
if ( ! $force && '' !== $current_alt && false !== $current_alt ) { |
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++$stats['skipped']; |
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++$processed; |
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$progress->tick(); |
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continue; |
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} |
| 350 |
|
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$result = $ability->execute( array( 'attachment_id' => $id ) ); |
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|
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if ( is_wp_error( $result ) ) { |
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++$stats['failed']; |
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WP_CLI::warning( sprintf( 'ID %d: %s', $id, $result->get_error_message() ) ); |
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++$processed; |
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$progress->tick(); |
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continue; |
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} |
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|
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$alt_text = $result['alt_text'] ?? ''; |
| 362 |
$is_decorative = ! empty( $result['is_decorative'] ); |
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|
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update_post_meta( $id, '_wp_attachment_image_alt', $alt_text ); |
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|
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if ( $is_decorative ) { |
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++$stats['decorative']; |
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} else { |
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++$stats['generated']; |
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} |
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|
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++$processed; |
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$progress->tick(); |
| 374 |
|
| 375 |
if ( $delay_ms <= 0 ) { |
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continue; |
| 377 |
} |
| 378 |
|
| 379 |
usleep( $delay_ms * 1000 ); |
| 380 |
} |
| 381 |
|
| 382 |
$this->free_batch_memory(); |
| 383 |
} |
| 384 |
|
| 385 |
$progress->finish(); |
| 386 |
|
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return $stats; |
| 388 |
} |
| 389 |
|
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/** |
| 391 |
* Prints the summary table after processing. |
| 392 |
* |
| 393 |
* @param array{generated: int, decorative: int, skipped: int, failed: int} $stats Processing statistics. |
| 394 |
*/ |
| 395 |
private function print_summary( array $stats ): void { |
| 396 |
WP_CLI::log( '' ); |
| 397 |
|
| 398 |
$items = array( |
| 399 |
array( |
| 400 |
'Metric' => 'Generated', |
| 401 |
'Count' => $stats['generated'], |
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), |
| 403 |
array( |
| 404 |
'Metric' => 'Decorative', |
| 405 |
'Count' => $stats['decorative'], |
| 406 |
), |
| 407 |
array( |
| 408 |
'Metric' => 'Skipped', |
| 409 |
'Count' => $stats['skipped'], |
| 410 |
), |
| 411 |
array( |
| 412 |
'Metric' => 'Failed', |
| 413 |
'Count' => $stats['failed'], |
| 414 |
), |
| 415 |
); |
| 416 |
|
| 417 |
Utils\format_items( 'table', $items, array( 'Metric', 'Count' ) ); |
| 418 |
|
| 419 |
$total = $stats['generated'] + $stats['decorative']; |
| 420 |
if ( $total > 0 ) { |
| 421 |
WP_CLI::success( sprintf( 'Generated alt text for %d image(s).', $total ) ); |
| 422 |
} else { |
| 423 |
WP_CLI::log( 'No alt text was generated.' ); |
| 424 |
} |
| 425 |
} |
| 426 |
|
| 427 |
/** |
| 428 |
* Frees memory held between batches so long-running CLI runs do not exhaust it. |
| 429 |
* |
| 430 |
* Uses `wp_cache_flush_runtime()` (WP 6.0+) to drop the in-memory portion of |
| 431 |
* the object cache without touching persistent backends like Redis. Falls |
| 432 |
* back to a no-op when the helper is unavailable. Also resets the query log |
| 433 |
* so it does not grow unbounded when `SAVEQUERIES` is enabled. |
| 434 |
*/ |
| 435 |
private function free_batch_memory(): void { |
| 436 |
global $wpdb; |
| 437 |
|
| 438 |
$wpdb->queries = array(); |
| 439 |
|
| 440 |
if ( ! function_exists( 'wp_cache_flush_runtime' ) ) { |
| 441 |
return; |
| 442 |
} |
| 443 |
|
| 444 |
wp_cache_flush_runtime(); |
| 445 |
} |
| 446 |
} |
| 447 |
|
