How Can I Create Robust Regular Expressions to Match URLs with and without Protocol Prefixes?

Matching URLs: A Comprehensive Regular Expression Approach

When extracting URLs from input, it's crucial to have a robust regular expression that can handle various scenarios. In this case, the provided regular expression fails to match URLs without the "http" or "https" protocol prefix. To address this challenge, we propose two alternative regular expressions:

For URLs Requiring an HTTP/HTTPS Protocol:

https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)

For URLs Without an HTTP/HTTPS Protocol Requirement:

[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)

These regular expressions effectively capture URLs with or without the protocol prefix. For experimental purposes, you can test these expressions at http://regexr.com?37i6s (with protocol prefix) and http://regexr.com/3e6m0 (without protocol prefix).

Below is an example JavaScript implementation:

const expression = /[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)/gi;
const regex = new RegExp(expression);
const t = 'www.google.com';

if (t.match(regex)) {
  alert("Successful match");
} else {
  alert("No match");
}

The above is the detailed content of How Can I Create Robust Regular Expressions to Match URLs with and without Protocol Prefixes?. For more information, please follow other related articles on the PHP Chinese website!