A URL is in the form of :$///.$ In order to be a valid URL, it must fulfill the following requirements:

Protocol: This can be any value from given list, such as http$,$ https$,$ or ftp$.$

Hostname: Any string

File extension: fileinfo can be any filename, but it must have an extension from given list $($such as $.$html$,.$csv$,.$docx, $.$jpg$,.$png$,$ or $.$gif$).$