Validation rule for valid utf-8 strings

[cweiske]

Now and then I get exceptions in my Sentry monitoring system that were caused by security scanners sending requests with invalid UTF-8 characters in parameter strings:

json_encode error: Malformed UTF-8 characters, possibly incorrectly encoded

I would like to reject requests with strings containing invalid utf-8 characters, but Laravel contains no such validation rule.

A solution would be to use mb_check_encoding for a rule.

[shaedrich]

Maybe, the ascii rule should be merged into the string rule as an option so utf8 could be an option as well 🤔