Extract domain information from a URL with and without regex

At times Php developers need to parse domain information from a given url , Usually a $_SERVER['REQUEST_URI'] , The php function www.php.net/parse_url is used to extract domain name, Variables from a url string, The list of information extracted (Return values) from parse url are:-

• scheme – e.g. http, https, etc.
• host:- the domain name( www.google.com)
• port:- the number of port used
• user :- username if specified on domain url
• pass :- password if specified on domain url
• path :- path of the page after the url
• query – after the question mark ?
• fragment – after the hashmark #

After parsing the url contents , there are still a lot of words that are url encoded , Which contains %20 between words. These can be parsed via www.php.net/urldecode .

A alternative method which can be used to parse a url contents is to use regex (regular expression) for

$r = “(?:([a-z0-9+-._]+)://)?”;
$r .= “(?:”;
$r .= “(?:((?:[a-z0-9-._~!$&'()*+,;=:]|%[0-9a-f]{2})*)@)?”;
$r .= “(?:\[((?:[a-z0-9:])*)\])?”;
$r .= “((?:[a-z0-9-._~!$&'()*+,;=]|%[0-9a-f]{2})*)”;
$r .= “(?::(\d*))?”;
$r .= “(/(?:[a-z0-9-._~!$&'()*+,;=:@/]|%[0-9a-f]{2})*)?”;
$r .= “|”;
$r .= “(/?”;
$r .= “(?:[a-z0-9-._~!$&'()*+,;=:@]|%[0-9a-f]{2})+”;
$r .= “(?:[a-z0-9-._~!$&'()*+,;=:@\/]|%[0-9a-f]{2})*”;
$r .= “)?”;
$r .= “)”;
$r .= “(?:\?((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9a-f]{2})*))?”;
$r .= “(?:#((?:[a-z0-9-._~!$&'()*+,;=:\/?@]|%[0-9a-f]{2})*))?”;
preg_match(“`$r`i”, $url, $match);

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Tagged as: php, regex