wpsc_get_accept_header() │ WPSCache 1.0

Returns a string containing a sanitized version of the Accept header. For now, this can only respond with text/html or application/json - used to differentiate between pages which may or may not be cacheable.

Hooks from the function

Returns

null. Nothing (null).

Usage

wpsc_get_accept_header();

wpsc_get_accept_header() code WPSCache 3.1.0

wp-super-cache/wp-cache-phase2.php 
function wpsc_get_accept_header() {
	static $accept = 'N/A';

	if ( $accept === 'N/A' ) {
		$accept_headers = apply_filters( 'wpsc_accept_headers', array( 'application/json', 'application/activity+json', 'application/ld+json' ) );
		$accept_headers = array_map( 'strtolower', $accept_headers );
		// phpcs:ignore WordPress.NamingConventions.ValidVariableName.VariableNotSnakeCase
		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.MissingUnslash -- $accept is checked and set below.
		$accept = isset( $_SERVER['HTTP_ACCEPT'] ) ? strtolower( filter_var( $_SERVER['HTTP_ACCEPT'] ) ) : '';

		foreach ( $accept_headers as $header ) {
			if ( str_contains( $accept, $header ) ) {
				$accept = 'application/json';
			}
		}

		if ( $accept !== 'application/json' ) {
			$accept = 'text/html';
		}

		wp_cache_debug( 'ACCEPT: ' . $accept );
	}

	return $accept;
}