WP SMUSH

WP - WP-CONTENT - PLUGIN - WP-SMUSHIT - LIB - CLASS-WP-SMUSH.PHP

1. if ( empty( $api_key ) ) {

   return false -> true;

   }

.....

2. 

//Flag to check if we need to revalidate the key

$revalidate = false -> true;

$api_auth = get_site_option( 'wp_smush_api_auth' );

//Check if need to revalidate

if ( ! $api_auth || empty( $api_auth ) || empty( $api_auth[ $api_key ] ) ) {

$revalidate = true;

} else {

$last_checked = $api_auth[ $api_key ]['timestamp'];

$valid        = $api_auth[ $api_key ]['validity'];

$diff = current_time( 'timestamp' ) - $last_checked;

//Difference in hours

$diff_h = $diff / 3600;

//Difference in minutes

$diff_m = $diff / 60;

switch ( $valid ) {

3.

}

$this->is_pro = ( 'valid' == $valid -> valid );

return $this->is_pro;

}