How to Detect URLs of Varying Formats Using Regular Expressions?

Detecting URLs with Varying Formats Using Regular Expressions

Regular expressions provide a powerful way to extract data from complex strings, including URLs. Whether you're working with URLs containing "http://www" prefixes or not, a comprehensive regular expression can cater to your needs.

The following expression has been crafted to match URLs with and without the "http://www" prefix:

((https?|ftp)://)?([a-z0-9+!*(),;?&=$_.-]+(:[a-z0-9+!*(),;?&=$_.-]+)?@)?([a-z0-9\-\.]*)\.(([a-z]{2,4})|([0-9]{1,3}\.([0-9]{1,3})\.([0-9]{1,3})))(:[0-9]{2,5})?(/([a-z0-9+$_%-]\.?)+)*/?(\?[a-z+&$_.-][a-z0-9;:@&%=+/$_.-]*)?(#[a-z_.-][a-z0-9+$%_.-]*)?

This expression incorporates the following components:

• Scheme: "(https?|ftp)://"
• User and Password: "([a-z0-9 !*(),;?&=$_.-] (:[a-z0-9 !*(),;?&=$_.-] )?@)"
• Host or IP Address: "([a-z0-9-.]*).(([a-z]{2,4})|([0-9]{1,3}.([0-9]{1,3}).([0-9]{1,3})))"
• Port: "(:[0-9]{2,5})?"
• Path: "(/([a-z0-9 $_%-].?) )*/?"
• GET Query: "(?a-z &$_.-*)?"
• Anchor: "(#a-z_.-*)?"

To utilize this expression, you can employ the PHP code below:

if(preg_match("~^$regex$~i", 'www.example.com/etcetc', $m))
    var_dump($m);

if(preg_match("~^$regex$~i", 'http://www.example.com/etcetc', $m))
    var_dump($m);

This code will successfully match both URLs, regardless of the presence of the "http://www" prefix.

The above is the detailed content of How to Detect URLs of Varying Formats Using Regular Expressions?. For more information, please follow other related articles on the PHP Chinese website!