CODEWITHSUNDEEP
objective-cregexemail-validation
ios developer
ios developer

Reputation: 3473

Regex for Email validation in objective c

I want to validate email id :

[email protected] :-- Valid

[email protected] : invalid

As per my knowledge multiple dots are not allowed after "@" in email id. Please advice how can i detect the more the one dots after @ and and check the validation.

I am using below regex for email validation. both are working fine. But not able to check multiple dots after @ symbols.

 NSString *emailRegex =
    @"(?:[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+(?:\\.[a-z0-9!#$%\\&'*+/=?\\^_`{|}"
    @"~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\"
    @"x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-"
    @"z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5"
    @"]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-"
    @"9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21"
    @"-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES[c] %@", emailRegex];

    return [emailTest evaluateWithObject:email];

I also tried this : 

NSString *regex1 = @"\\A[a-z0-9]+([-._][a-z0-9]+)*@([a-z0-9]+(-[a-z0-9]+)*\\.)+[a-z]{2,4}\\z";
    NSString *regex2 = @"^(?=.{1,64}@.{4,64}$)(?=.{6,100}$).*";
    NSPredicate *test1 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex1];
    NSPredicate *test2 = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex2];
    return [test1 evaluateWithObject:email] && [test2 evaluateWithObject:email];

Upvotes: 0

Views: 2549

Answers (4)

93sauu
93sauu

Reputation: 4097

The expression, that you are using, satisfies the RFC 5322. Multiples dots after @ are perfectly valid for hostname. How other user you tell you if you limit to one dot, you were blocking many domains.

+ (BOOL) validateEmail: (NSString *) candidate;
{
    // The Official Standard: RFC 5322
    // http://www.regular-expressions.info/email.html
    NSString *emailRegEx =
    @"(?:[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+(?:\\.[a-z0-9!#$%\\&'*+/=?\\^_`{|}"
    @"~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\"
    @"x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")@(?:(?:[a-z0-9](?:[a-"
    @"z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5"
    @"]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-"
    @"9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21"
    @"-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])";

    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegEx];
    return [predicate evaluateWithObject:candidate];
}

Upvotes: 1

Sid Mhatre
Sid Mhatre

Reputation: 3417

For : [email protected]

NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

For exclude check multiple dots after @ symbols. [email protected] :-- Valid

[email protected] : invalid

exclude dot from @[A-Za-z0-9.-] 

NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

Upvotes: 0

Pooja Gupta
Pooja Gupta

Reputation: 793

Please try this 

+ (BOOL)isValidEmail: (NSString *)email {
        NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
        NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];

        return [emailTest evaluateWithObject:email];
 }

Upvotes: 2

Itai Ferber
Itai Ferber

Reputation: 29764

Don't use a regex for this, use NSDataDetector:

NSError *error = nil;
NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingTypeLink error:&error];
if (!detector) { /* handle error */ }

You can then use detector the same as you would an NSRegularExpression:

NSString *email = @"[email protected]";        
NSTextCheckingResult *match = [detector firstMatchInString:email options:0 range:NSMakeRange(0, email.length)];
NSLog(@"%@", match);

There are many hidden pitfalls to matching well-known types like this via regex (as you build in assumptions about what is valid, as you have in your question; subdomains and multi-level TLDs are certainly valid); avoid doing it yourself where possible.

Upvotes: 3

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