WP_Error

WordPress Error class.


Description Description

Container for checking for WordPress errors and error messages. Return WP_Error and use is_wp_error() to check if this class is returned. Many core WordPress functions pass this class in the event of an error and if not handled properly will result in code errors.


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More Information More Information

WP_Error is a class that makes error handling within plugins and WordPress itself much easier.

Instances of WP_Error store error codes and messages representing one or more errors, and whether or not a variable is an instance of WP_Error can be determined using the is_wp_error() function.

Error Codes Error Codes

Error codes are slugs that are used to identify each error. They are mostly useful when a piece of code can produce several different errors, and you want to handle each of those errors differently.

The error codes used in WordPress are not integers, but strings, with any spaces between words replaced with underscores (example: an_error_code). The error codes used in WordPress are usually based on the error message associated with that code.

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Properties Properties

Please refer source code for the complete lists of properties. Below description may cover some of them.

$errors
Array containing the list of errors.
$error_data
Array containing the list of data for error codes.

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  • see is_wp_error() for more information on trapping for errors (particularly useful when faced with the dreaded ‘Catchable fatal error: Object of class WP_Error could not be converted to string’)

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Source Source

File: wp-includes/class-wp-error.php

class WP_Error {
	/**
	 * Stores the list of errors.
	 *
	 * @since 2.1.0
	 * @var array
	 */
	public $errors = array();

	/**
	 * Stores the most recently added data for each error code.
	 *
	 * @since 2.1.0
	 * @var array
	 */
	public $error_data = array();

	/**
	 * Stores previously added data added for error codes, oldest-to-newest by code.
	 *
	 * @since 5.6.0
	 * @var array[]
	 */
	protected $additional_data = array();

	/**
	 * Initializes the error.
	 *
	 * If `$code` is empty, the other parameters will be ignored.
	 * When `$code` is not empty, `$message` will be used even if
	 * it is empty. The `$data` parameter will be used only if it
	 * is not empty.
	 *
	 * Though the class is constructed with a single error code and
	 * message, multiple codes can be added using the `add()` method.
	 *
	 * @since 2.1.0
	 *
	 * @param string|int $code    Error code.
	 * @param string     $message Error message.
	 * @param mixed      $data    Optional. Error data.
	 */
	public function __construct( $code = '', $message = '', $data = '' ) {
		if ( empty( $code ) ) {
			return;
		}

		$this->add( $code, $message, $data );
	}

	/**
	 * Retrieves all error codes.
	 *
	 * @since 2.1.0
	 *
	 * @return array List of error codes, if available.
	 */
	public function get_error_codes() {
		if ( ! $this->has_errors() ) {
			return array();
		}

		return array_keys( $this->errors );
	}

	/**
	 * Retrieves the first error code available.
	 *
	 * @since 2.1.0
	 *
	 * @return string|int Empty string, if no error codes.
	 */
	public function get_error_code() {
		$codes = $this->get_error_codes();

		if ( empty( $codes ) ) {
			return '';
		}

		return $codes[0];
	}

	/**
	 * Retrieves all error messages, or the error messages for the given error code.
	 *
	 * @since 2.1.0
	 *
	 * @param string|int $code Optional. Retrieve messages matching code, if exists.
	 * @return array Error strings on success, or empty array if there are none.
	 */
	public function get_error_messages( $code = '' ) {
		// Return all messages if no code specified.
		if ( empty( $code ) ) {
			$all_messages = array();
			foreach ( (array) $this->errors as $code => $messages ) {
				$all_messages = array_merge( $all_messages, $messages );
			}

			return $all_messages;
		}

		if ( isset( $this->errors[ $code ] ) ) {
			return $this->errors[ $code ];
		} else {
			return array();
		}
	}

	/**
	 * Gets a single error message.
	 *
	 * This will get the first message available for the code. If no code is
	 * given then the first code available will be used.
	 *
	 * @since 2.1.0
	 *
	 * @param string|int $code Optional. Error code to retrieve message.
	 * @return string The error message.
	 */
	public function get_error_message( $code = '' ) {
		if ( empty( $code ) ) {
			$code = $this->get_error_code();
		}
		$messages = $this->get_error_messages( $code );
		if ( empty( $messages ) ) {
			return '';
		}
		return $messages[0];
	}

	/**
	 * Retrieves the most recently added error data for an error code.
	 *
	 * @since 2.1.0
	 *
	 * @param string|int $code Optional. Error code.
	 * @return mixed Error data, if it exists.
	 */
	public function get_error_data( $code = '' ) {
		if ( empty( $code ) ) {
			$code = $this->get_error_code();
		}

		if ( isset( $this->error_data[ $code ] ) ) {
			return $this->error_data[ $code ];
		}
	}

	/**
	 * Verifies if the instance contains errors.
	 *
	 * @since 5.1.0
	 *
	 * @return bool If the instance contains errors.
	 */
	public function has_errors() {
		if ( ! empty( $this->errors ) ) {
			return true;
		}
		return false;
	}

	/**
	 * Adds an error or appends an additional message to an existing error.
	 *
	 * @since 2.1.0
	 *
	 * @param string|int $code    Error code.
	 * @param string     $message Error message.
	 * @param mixed      $data    Optional. Error data.
	 */
	public function add( $code, $message, $data = '' ) {
		$this->errors[ $code ][] = $message;

		if ( ! empty( $data ) ) {
			$this->add_data( $data, $code );
		}

		/**
		 * Fires when an error is added to a WP_Error object.
		 *
		 * @since 5.6.0
		 *
		 * @param string|int $code     Error code.
		 * @param string     $message  Error message.
		 * @param mixed      $data     Error data. Might be empty.
		 * @param WP_Error   $wp_error The WP_Error object.
		 */
		do_action( 'wp_error_added', $code, $message, $data, $this );
	}

	/**
	 * Adds data to an error with the given code.
	 *
	 * @since 2.1.0
	 * @since 5.6.0 Errors can now contain more than one item of error data. {@see WP_Error::$additional_data}.
	 *
	 * @param mixed      $data Error data.
	 * @param string|int $code Error code.
	 */
	public function add_data( $data, $code = '' ) {
		if ( empty( $code ) ) {
			$code = $this->get_error_code();
		}

		if ( isset( $this->error_data[ $code ] ) ) {
			$this->additional_data[ $code ][] = $this->error_data[ $code ];
		}

		$this->error_data[ $code ] = $data;
	}

	/**
	 * Retrieves all error data for an error code in the order in which the data was added.
	 *
	 * @since 5.6.0
	 *
	 * @param string|int $code Error code.
	 * @return mixed[] Array of error data, if it exists.
	 */
	public function get_all_error_data( $code = '' ) {
		if ( empty( $code ) ) {
			$code = $this->get_error_code();
		}

		$data = array();

		if ( isset( $this->additional_data[ $code ] ) ) {
			$data = $this->additional_data[ $code ];
		}

		if ( isset( $this->error_data[ $code ] ) ) {
			$data[] = $this->error_data[ $code ];
		}

		return $data;
	}

	/**
	 * Removes the specified error.
	 *
	 * This function removes all error messages associated with the specified
	 * error code, along with any error data for that code.
	 *
	 * @since 4.1.0
	 *
	 * @param string|int $code Error code.
	 */
	public function remove( $code ) {
		unset( $this->errors[ $code ] );
		unset( $this->error_data[ $code ] );
		unset( $this->additional_data[ $code ] );
	}

	/**
	 * Merges the errors in the given error object into this one.
	 *
	 * @since 5.6.0
	 *
	 * @param WP_Error $error Error object to merge.
	 */
	public function merge_from( WP_Error $error ) {
		static::copy_errors( $error, $this );
	}

	/**
	 * Exports the errors in this object into the given one.
	 *
	 * @since 5.6.0
	 *
	 * @param WP_Error $error Error object to export into.
	 */
	public function export_to( WP_Error $error ) {
		static::copy_errors( $this, $error );
	}

	/**
	 * Copies errors from one WP_Error instance to another.
	 *
	 * @since 5.6.0
	 *
	 * @param WP_Error $from The WP_Error to copy from.
	 * @param WP_Error $to   The WP_Error to copy to.
	 */
	protected static function copy_errors( WP_Error $from, WP_Error $to ) {
		foreach ( $from->get_error_codes() as $code ) {
			foreach ( $from->get_error_messages( $code ) as $error_message ) {
				$to->add( $code, $error_message );
			}

			foreach ( $from->get_all_error_data( $code ) as $data ) {
				$to->add_data( $data, $code );
			}
		}
	}
}

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Methods Methods

  • __construct — Initializes the error.
  • __get — Make private properties readable for backwards compatibility.
  • __isset — Make private properties checkable for backwards compatibility.
  • __set — Make private properties settable for backwards compatibility.
  • __unset — Make private properties un-settable for backwards compatibility.
  • add — Adds an error or appends an additional message to an existing error.
  • add_data — Adds data to an error with the given code.
  • copy_errors — Copies errors from one WP_Error instance to another.
  • export_to — Exports the errors in this object into the given one.
  • get_all_error_data — Retrieves all error data for an error code in the order in which the data was added.
  • get_error_code — Retrieves the first error code available.
  • get_error_codes — Retrieves all error codes.
  • get_error_data — Retrieves the most recently added error data for an error code.
  • get_error_message — Gets a single error message.
  • get_error_messages — Retrieves all error messages, or the error messages for the given error code.
  • has_errors — Verifies if the instance contains errors.
  • merge_from — Merges the errors in the given error object into this one.
  • remove — Removes the specified error.

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Changelog Changelog

Changelog
Version Description
2.1.0 Introduced.

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