Firebase Rules Regex Birthday

问题

I am trying to validate birthdays using the following regex:

^(?:(?:31(\/|-|\.)(?:0?[13578]|1[02]))\1|(?:(?:29|30)(\/|-|\.)(?:0?[1,3-9]|1[0-2])\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:29(\/|-|\.)0?2\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:(?:0?[1-9])|(?:1[0-2]))\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$

This regex works when tested in an online regex tester, but when I try to use this regex inside my firebase rules, Firebase seems to not accept it. I also tried doubling my backslashes and still no luck.

This is my firebase rule:

".validate": "newData.isString() && newData.val().matches(/^(?:(?:31(\/|-|\.)(?:0?[13578]|1[02]))\1|(?:(?:29|30)(\/|-|\.)(?:0?[1,3-9]|1[0-2])\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:29(\/|-|\.)0?2\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\d|2[0-8])(\/|-|\.)(?:(?:0?[1-9])|(?:1[0-2]))\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$/)"

This is the error I get on Firebase: "Illegal regular expression, unescaped ^, ^ can only appear at the end of regular expressions"

How can I tweak this regex to get it working on Firebase?

回答1:

You need to do two things here:

• make sure all backslashes are doubled
• turn all non-capturing groups into capturing ones and re-adjust the backreferences (note that redundant capturing groups should be eliminated) (note you can't use \15 as backreference, it seems only 1 to 9 backreferences are supported)
• re-vamp the pattern so that the ^ start of string anchor appeared at the beginning and $ only at the end of the regular expression (otherwise, you will get the illegal regex exception). It is easy to do here as your pattern is of the ^a1$|^a2$|^a3$ type, and it is equal to ^(?:a1|a2|a3)$.

The pattern should look like

newData.val().matches(/^((31([-\\/.])(0?[13578]|1[02])\\3|(29|30)([-\\/.])(0?[13-9]|1[0-2])\\6)(1[6-9]|[2-9]\\d)?\\d{2}|29([-\\/.])0?2\\9((1[6-9]|[2-9]\\d)?(0[48]|[2468][048]|[13579][26])|(16|[2468][048]|[3579][26])00)|(0?[1-9]|1\\d|2[0-8])([-\\/.])(0?[1-9]|1[0-2])[-\\/.](1[6-9]|[2-9]\\d)?\\d{2})$/)

Note that I also turned (\/|-|\.) into ([-\/.]) (since a character class is more efficient than plain alternation with single-char alternatives) and remove a comma from [1,3-9] - it looks like a typo, you wanted to match 1 or a digit from 3 to 9, I believe, and a , is treated literally in a character class.

来源：https://stackoverflow.com/questions/50571573/firebase-rules-regex-birthday