Preferences error message

[mistic100]

I set up this regex validation for URL
https://github.com/mistic100/hain-plugin-rss/blob/master/preferences.json#L21

It works well but Hain directly displays the JSON schema error which is kinda ugly when using a pattern :

Does not match regular expression "(?(?:(http|https|ftp)://)?(?:((?:[^\W\s]|.|-|[:]{1})+)@{1})?((?:www.)?(?:[^\W\s]|.|-)+[.][^\W\s]{2,4}|localhost(?=/)|\d{1,3}.\d{1,3}.\d{1,3}.\d{1,3})(?::(\d_))?([/]?[^\s\?][/]{1})(?:/?([^\s\n\?\[\]\{\}\#](?:(?=.)){1}|[^\s\n\?\[\]\{\}\.\#])?([.]{1}[^\s\?\#])?)?(?:?{1}([^\s\n\#\[\]]))?([#][^\s\n]_)?)?"

Perhaps Hain could expose a way to customize the error message, for example by extending the JSON schema declaration with a "messages" field.

Similar question on other projects using JSON schema :
geraintluff/tv4#115 (comment)

[appetizermonster]

@mistic100 it looks your suggestion would be good solution for this, I think i can implement it by referencing your suggestion

[mistic100]

Perfect :-)
mistic100/hain-plugin-rss@0f60e0f#diff-db61577cf3cd56d46837c09775052b4bR10