wppaste
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IXR_Error::__construct( $code, $message )

Source
wp-includes/IXR/class-IXR-error.php:17

Stores an XML-RPC fault code and message on a new IXR_Error object, running the message through htmlspecialchars() before saving it. Both $code and $message are required, there are no default values, so calling the constructor without one triggers a PHP argument error. Custom XML-RPC callbacks and the wp_xmlrpc_server methods return an IXR_Error instance instead of a normal value whenever they need to signal a fault back to the client.

PHP5 constructor.

Compatibility

WordPress
core
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$code
$message

Code examples

Every example is editable and runs in a real WordPress booted in your browser by WordPress Playground. Press Run, then edit the code: clicking away re-runs it. Nothing is sent anywhere until you do.

Build an IXR_Error to signal a fault from a custom XML-RPC method

Create an IXR_Error directly and inspect the code and message it stores.

$error = new IXR_Error( 401, 'Sorry, you are not allowed to <em>do</em> that.' );

echo 'code: ' . esc_html( $error->code ) . "\n";
echo 'message: ' . esc_html( $error->message ) . "\n";

The <em> tags in the message are already turned into HTML entities by the constructor, so the output shows the escaped markup rather than rendered tags.

Return an IXR_Error from a custom XML-RPC callback when a post ID is invalid

Simulate an XML-RPC callback that looks up a post and returns an IXR_Error for a bad ID, using the baseline posts 1 to 5.

function wppaste_get_post_title_via_xmlrpc( $post_id ) {
    $post = get_post( (int) $post_id );

    if ( ! $post ) {
        return new IXR_Error( 404, 'Invalid post ID.' );
    }

    return $post->post_title;
}

$valid   = wppaste_get_post_title_via_xmlrpc( 1 );
$invalid = wppaste_get_post_title_via_xmlrpc( 999 );

echo 'valid lookup: ' . esc_html( $valid ) . "\n";

if ( $invalid instanceof IXR_Error ) {
    printf( 'invalid lookup error %d: %s' . "\n", $invalid->code, esc_html( $invalid->message ) );
}

Common problems and fixes · 3

Why does my error message show &amp; and &lt; instead of the actual characters?

The constructor runs $message through htmlspecialchars() before storing it, so any ampersands, quotes or angle brackets in the string you pass in come back HTML-encoded on $error->message.

Why do I get a PHP error about missing arguments when creating an IXR_Error?

$code and $message have no default values in the constructor signature, so both are required. Leaving either one out triggers PHP's own arguments-not-provided error rather than anything IXR_Error handles itself.

Can I change the error message after the object is created without it getting escaped?

Yes, and that is the pitfall: htmlspecialchars() only runs inside the constructor. If you assign $error->message = $new_text directly afterward, that new text bypasses the escaping entirely.

Alternatives and related functions

WP_Error
When you are building an error outside the XML-RPC transport, such as for the REST API, hooks or admin code, WP_Error is the standard WordPress object for that.
wp_xmlrpc_server::error
When you are adding a method inside a class that extends wp_xmlrpc_server, its error() helper builds and returns the IXR_Error for you.
IXR_Server::error
When you are writing directly against the IXR_Server class rather than the WordPress XML-RPC server subclass, its error() method wraps IXR_Error construction in the same way.

Performance profile

How much work a call to IXR_Error::__construct() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
10

Executed per call on PHP 8.5. The body compiles to 10.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
50

50 places in core call this, so the cost is paid more often than your own code shows.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost IXR_Error::__construct() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always10htmlspecialchars()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 10 instructions, 10 executed per call, 0 branches. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Used by · 50

Show all 50

Source code

View on Trac View on GitHub 

    function __construct( $code, $message )    {        $this->code = $code;        $this->message = htmlspecialchars($message);    }

Changelog

Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 6.8.8 tag, from src/wp-includes/IXR/class-IXR-error.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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