I want to validate a form input so that http:// and www is not allowed. Which REGEX would work?
For example:
Allowed
google.com
NOT Allowed
MODEL
VALID_DOMAIN_REGEX = ???
validates :domain, format: { with: VALID_DOMAIN_REGEX }
Since http:// contains so many forward slashes, this would be a good use for Ruby's %r{} regex literal syntax.
def has_forbidden_prefix?(string)
string =~ %r{^(http://|www)}
end
This will return nil, falsy, if the string does not start with http:// or www.
It will return 0, truthy (the offset of the first match) if the string does.
You can use validate :some_method_name to call a custom validation method in the model, I would structure it as follows
model MyThing
validate :no_forbidden_prefix
private
def has_forbidden_prefix?(string)
string =~ %r{^(http://|www)}
end
def no_forbidden_prefix
if has_forbidden_prefix?(uri)
errors.add :domain, 'The URI cannot start with "http://" or "www"'
end
end
end
This should do it for you:
/^[http\:\/\/|www].*/
For example:
1.9.2p320 :007 > "http://www.google.de".match /^[http\:\/\/|www].*/
=> #<MatchData "http://www.google.de">
1.9.2p320 :008 > "www.google.de".match /^[http\:\/\/|www].*/
=> #<MatchData "www.google.de">
1.9.2p320 :009 > "google.de".match /^[http\:\/\/|www].*/
=> nil
So it doenst match if its valid for your purposes...
[http\:\/\/|www] is a character class, maybe you intended to use grouping?