get_file_data() – Function | Developer.WordPress.org

Retrieves metadata from a file.

Description

Searches for metadata in the first 8 KB of a file, such as a plugin or theme.
Each piece of metadata must be on its own line. Fields can not span multiple lines, the value will get cut at the end of the first line.

If the file data is not within that first 8 KB, then the author should correct their plugin file and move the data headers to the top.

Parameters

$filestringrequired: Absolute path to the file.
$default_headersarrayrequired: List of headers, in the format array( 'HeaderKey' => 'Header Name' ).
$contextstringoptional: If specified adds filter hook 'extra_$context_headers'.

Default:''

Return

string[] Array of file header values keyed by header name.

Source

 *
 * @param string $file            Absolute path to the file.
 * @param array  $default_headers List of headers, in the format `array( 'HeaderKey' => 'Header Name' )`.
 * @param string $context         Optional. If specified adds filter hook 'extra_$context_headers'.
 *                                Default empty string.
 * @return string[] Array of file header values keyed by header name.
 */
function get_file_data( $file, $default_headers, $context = '' ) {
	// Pull only the first 8 KB of the file in.
	$file_data = file_get_contents( $file, false, null, 0, 8 * KB_IN_BYTES );

	if ( false === $file_data ) {
		$file_data = '';
	}

	// Make sure we catch CR-only line endings.
	$file_data = str_replace( "\r", "\n", $file_data );

	/**
	 * Filters extra file headers by context.
	 *
	 * The dynamic portion of the hook name, `$context`, refers to
	 * the context where extra headers might be loaded.
	 *
	 * @since 2.9.0
	 *
	 * @param array $extra_context_headers Empty array by default.
	 */
	$extra_headers = $context ? apply_filters( "extra_{$context}_headers", array() ) : array();
	if ( $extra_headers ) {
		$extra_headers = array_combine( $extra_headers, $extra_headers ); // Keys equal values.
		$all_headers   = array_merge( $extra_headers, (array) $default_headers );
	} else {
		$all_headers = $default_headers;
	}

	foreach ( $all_headers as $field => $regex ) {
		if ( preg_match( '/^(?:[ \t]*<\?php)?[ \t\/*#@]*' . preg_quote( $regex, '/' ) . ':(.*)$/mi', $file_data, $match ) && $match[1] ) {
			$all_headers[ $field ] = _cleanup_header_comment( $match[1] );

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Changelog

Version	Description
2.9.0	Introduced.

User Contributed Notes

Josh Smith 8 years ago

/**
 * Register stylesheet and scripts
 * Set the version of each the version of the plugin. 
 */
function register_plugin_styles_scripts() {
	// Set the file path to a variable.
	$file_path = plugin_dir_path( __DIR__ ) . 'example-plugin-file.php';
	// Read the version number from the main plugin file then set it to a variable.
	$plugin_data = get_file_data( $file_path, array(
		'Version' => 'Version'
	) );

	if ( ! empty( $plugin_data['Version'] ) ) {
		// The the value of the Version header to a variable.
		$ver = $plugin_data['Version'];

		// Use the variable, $ver, in more than one stylesheet/script to bust cache when the plugin gets updated.
		wp_enqueue_style( 'public-style', plugins_url( 'path/to/stylesheet.css' ), array(), $ver );
		wp_enqueue_script('public-script', plugins_url( 'path/to/script.js' ), array(), $ver , true);
	}
}

hozyali 8 years ago

Reading multiple header keys

<?php
	$filedata = get_file_data(plugin_dir_path(__FILE__) . '/dirName/index.php', array(
    'Page Name' => 'Page Name',
    'Preview Image' => 'Preview Image',
    'Template File' => 'Template File',
        ));
	print_r($filedata);
	?>

get_file_data( string $file, array $default_headers, string $context = '' ): string[]

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