Email Validation Regex

Question

We have special requirements for our email verification. We want to allow the following:

• First and last characters must be alphanumeric.
• The middle section also allows alphanumeric + the following 3 special characters .-_ (period, hyphen and underscore).
• Special characters cannot touch (2 periods cannot be next to eachother, or a hyphen underscore for instance).

So far I've managed to figure our how to check for alphanumeric: [^A-Za-z0-9 ]

But I'm completely stuck on the hardest part - the middle section. Thanks.

Answer 1

Before you go down the path of email validation with regex, have you tried filter_var() with FILTER_VALIDATE_EMAIL?

if(filter_var($email, FILTER_VALIDATE_EMAIL) !== false)
{
    // Valid email.
}