Once done, you can use the shortcode. It’s pretty simple: [show_file file="http://www.test.com/test.html"]
function show_file_func( $atts ) {
extract( shortcode_atts( array(
'file' => ''
), $atts ) );
if ($file!=''){
$request = wp_remote_get($file);
$response = wp_remote_retrieve_body( $request );
return $response;
}
}
add_shortcode( 'show_file', 'show_file_func' );