Function that checks whether the given URL exists (not a 404 page).

does-url-exist

<?php
/**
 * Figures out whether the given URL exists
 *
 * @param string
 * @return bool
 *
 * @since 0.0.1
 */
function does_url_exist( $url ) {

    $exists = false;
    $file_headers = @get_headers($url);

    if( $file_headers[0] === 'HTTP/1.0 404 Not Found' ){
        $exists = false;
    } else if ($file_headers[0] == 'HTTP/1.0 302 Found' && $file_headers[7] == 'HTTP/1.0 404 Not Found'){
        $exists = false;
    } else {
        $exists = true;
    }

    return $exists;

}