Rails: Allow only specific symbols and letters-CodePudding

Trying to write correct validation.

I have symbols/letters which can be only used:

ALLOWED_SYMBOLS = %w(/ @ _   - ( ) . , : ? ' & ; " 0 1 2 3 4 5 6 7 8 9 A a Ā ā Ą ą Ä ä B b C c Č č D d E e Ē ē Ę ę Ė ė F f G g Ģ ģ H h I i Ī ī Į į Y y J j K k Ķ ķ L l Ļ ļ M m N n Ņ ņ O o Õ õ Ö ö P p Q q R r S s Š š T t U u Ū ū Ü ü V v W w Z z Ž ž X x)

Afterwards i'm trying to validate it

validates :reference inclusion: { in: ALLOWED_SYMBOLS, allow_blank: true }

But it's not working properly as if i'm writing 2 or more allowed symbols i get an error, it does not happen when i type only 1 allowed one.

Looking forward for your help. The idea is to only allow mentioned symbols(they can be duplicated and such)

Rails 5.2

CodePudding user response：

Your problem is that validating inclusion: {in: ...} is saying "the value must be one of the items in the list" -- which is not what you want at all.

Instead, what you're trying to check is "does reference only contain characters from this list?".

I would solve that with a regex. Suppose, for example, you wanted a string to only contain the characters a, b, c, d, ..., z. Then you could check the format with:

/\A[a-z]*\z/

Where \A means "start of string", \z means "end of string" and [a-z]* means "zero or more letters from the collection: a, b, c, ...., z".

However, your scenario is a little more awkward because you don't have a nice character set/range like [a-z]. You could write that very verbosely (but it's difficult to read/reuse the code):

/\A[\/@_ \-().,:?'&;"0123456789ĀāĄąÄäBb....]*\z/

Or, better, you could get a little fancy and convert the constant into a suitable regex:

/\A#{Regexp.union(*ALLOWED_SYMBOLS)}*\z/

And therefore your final answer is to replace this:

validates :reference inclusion: { in: ALLOWED_SYMBOLS, allow_blank: true }

With this:

validates :reference, format: { with: /\A#{Regexp.union(*ALLOWED_SYMBOLS)}*\z/ }