Matches a variable with the following syntax; = example string foo = ...

This regular expression is used to validated the filename of Gateway plugins.

Regular expression ^(?:https?:)?(?:\/\/)?(?:+@)?(?:www\.)?(+) used below extracts domain with subdomains out of a full url. It skips protocol (ex: https:), "//", "@", www subdomain and then captures everything (ex: domain) before ":" or "/" or end of line.