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is_blog_installed › WordPress Function

Since2.1.0
Deprecatedn/a
› is_blog_installed ( No parameters )
Returns:
  • (bool) Whether the site is already installed.
Defined at:
Codex:

Determines whether WordPress is already installed.

The cache will be checked first. If you have a cache plugin, which saves the cache values, then this will work. If you use the default WordPress cache, and the database goes away, then you might have problems. Checks for the 'siteurl' option for whether WordPress is installed. For more information on this and similar theme functions, check out the {@link Conditional Tags} article in the Theme Developer Handbook.


Related Functions: ms_not_installed, wp_not_installed, is_subdomain_install, is_blog_user, is_blog_admin

Source 

function is_blog_installed() {
	global $wpdb;

	/*
	 * Check cache first. If options table goes away and we have true
	 * cached, oh well.
	 */
	if ( wp_cache_get( 'is_blog_installed' ) ) {
		return true;
	}

	$suppress = $wpdb->suppress_errors();

	if ( ! wp_installing() ) {
		$alloptions = wp_load_alloptions();
	}

	// If siteurl is not set to autoload, check it specifically.
	if ( ! isset( $alloptions['siteurl'] ) ) {
		$installed = $wpdb->get_var( "SELECT option_value FROM $wpdb->options WHERE option_name = 'siteurl'" );
	} else {
		$installed = $alloptions['siteurl'];
	}

	$wpdb->suppress_errors( $suppress );

	$installed = ! empty( $installed );
	wp_cache_set( 'is_blog_installed', $installed );

	if ( $installed ) {
		return true;
	}

	// If visiting repair.php, return true and let it take over.
	if ( defined( 'WP_REPAIRING' ) ) {
		return true;
	}

	$suppress = $wpdb->suppress_errors();

	/*
	 * Loop over the WP tables. If none exist, then scratch installation is allowed.
	 * If one or more exist, suggest table repair since we got here because the
	 * options table could not be accessed.
	 */
	$wp_tables = $wpdb->tables();
	foreach ( $wp_tables as $table ) {
		// The existence of custom user tables shouldn't suggest an unwise state or prevent a clean installation.
		if ( defined( 'CUSTOM_USER_TABLE' ) && CUSTOM_USER_TABLE === $table ) {
			continue;
		}

		if ( defined( 'CUSTOM_USER_META_TABLE' ) && CUSTOM_USER_META_TABLE === $table ) {
			continue;
		}

		$described_table = $wpdb->get_results( "DESCRIBE $table;" );
		if (
			( ! $described_table && empty( $wpdb->last_error ) ) ||
			( is_array( $described_table ) && 0 === count( $described_table ) )
		) {
			continue;
		}

		// One or more tables exist. This is not good.

		wp_load_translations_early();

		// Die with a DB error.
		$wpdb->error = sprintf(
			/* translators: %s: Database repair URL. */
			__( 'One or more database tables are unavailable. The database may need to be <a href="%s">repaired</a>.' ),
			'maint/repair.php?referrer=is_blog_installed'
		);

		dead_db();
	}

	$wpdb->suppress_errors( $suppress );

	wp_cache_set( 'is_blog_installed', false );

	return false;
}