Source View: wp_headers

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Understanding Source Code

The best way to understand what a hook does is to look at where it occurs in the source code.

  • Action hooks look like this: do_action( "hook_name" )
  • Filter hooks look like this: apply_filters( "hook_name", "what_to_filter" ).

Remember, this hook may occur in more than one file. Moreover, the hook's context may change from version to version.

Source View

Line Code
439
440           /**
441            * Filter the HTTP headers before they're sent to the browser.
442            *
443            * @since 2.8.0
444            *
445            * @param array $headers The list of headers to be sent.
446            * @param WP    $this    Current WordPress environment instance.
447            */
448           $headers = apply_filters( 'wp_headers', $headers, $this );
449
450           if ( ! empty( $status ) )
451                status_header( $status );
452
453           // If Last-Modified is set to false, it should not be sent (no-cache situation).
454           if ( isset( $headers['Last-Modified'] ) && false === $headers['Last-Modified'] ) {
455                unset( $headers['Last-Modified'] );
456
457                // In PHP 5.3+, make sure we are not sending a Last-Modified header.