Question

How to make sure that the domain name match those 3 simple criterias :

• Ends with .com / .net

Must not start with

• http:// or https://
• http://www. or https://www.

I’ve managed to understand this part of the regex which correspond with the first criteria :

/.*(\.com|\.net)$/

But i have no idea how to achieve the 2 others conditions to make an unique regex.

Thanks for your help.

Answer 1

A regex solution is easy. Simply assert a negative lookahead at the start of the string like so: (With comments…)

if (preg_match('%
    # Match non-http ,com or .net domain.
    ^             # Anchor to start of string.
    (?!           # Assert that this URL is NOT...
      https?://   # HTTP or HTTPS scheme with
      (?:www\.)?  # optional www. subdomain.
    )             # End negative lookahead.
    .*            # Match up to TLD.
    \.            # Last literal dot before TLD.
    (?:           # Group for TLD alternatives.
      net         # Either .net
    | com         # or .com.
    )             # End group of TLD alts.
    $             # Anchor to end of string.
    %xi', $text)) {
    // It matches.
} else {
    // It doesn't match.
}

Note that since: http://www. is a subset of: http://, the expression for the optional www. is not necessary. Here is a shorter version:

if (preg_match('%^(?!https?://).*\.(?:net|com)$%i', $text)) {
    // It matches.
} else {
    // It doesn't match.
}

Simple regex to the rescue!