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
463
464           /**
465            * Filter the HTTP headers before they're sent to the browser.
466            *
467            * @since 2.8.0
468            *
469            * @param array $headers The list of headers to be sent.
470            * @param WP    $this    Current WordPress environment instance.
471            */
472           $headers = apply_filters( 'wp_headers', $headers, $this );
473
474           if ( ! empty( $status ) )
475                status_header( $status );
476
477           // If Last-Modified is set to false, it should not be sent (no-cache situation).
478           if ( isset( $headers['Last-Modified'] ) && false === $headers['Last-Modified'] ) {
479                unset( $headers['Last-Modified'] );
480
481                // In PHP 5.3+, make sure we are not sending a Last-Modified header.