Php get root domain name method summary

This article mainly introduces the php method for obtaining the root domain name. The example summarizes common methods for obtaining the root domain name by php, which is a very practical technique, for more information about how to obtain the root domain name in php, see the examples in this article. The specific implementation method is as follows:

If you only get the domain name currently accessing your page, you only need to use the HTTP_HOST function in php. if you want to extract the url root domain name, you need regular expressions, let's take a look at several specific instances.

It is very easy to obtain the current domain name:

The code is as follows:

<? Php
// Obtain the current domain name:
Echo $ _ SERVER ['server _ name'];
// Obtain the source URL, that is, click the previous URL on this page.
Echo $ _ SERVER ["HTTP_REFERER"];
$ _ SERVER ['request _ URI ']; // Obtain the suffix of the current domain name
$ _ SERVER ['http _ host']; // Obtain the current domain name
Dirname (_ FILE _); // Obtain the physical path of the current FILE
Dirname (_ FILE _). "/../"; // Obtain the upper-level physical path of the current FILE
?>

Example 1

The code is as follows:

Function getUrlRoot ($ url ){
# Add the header and tail
$ Url = $ url ."/";
# Determining domain names
Preg_match ("/(\ w *):\/\/)? \ W *\.? ([\ W |-] * \. (com.cn | net.cn | gov.cn | org.cn | com | net | cn | org | asia | tel | mobi | me | TV | biz | cc | name | info ))
\\// ", $ Url, $ ohurl );
# Determining IP addresses
If ($ ohurl [3] = ''){
Preg_match ("/(\ d + \.) {3} \ d +) \ //", $ url, $ ohip );
Return $ ohip [1];
}
Return $ ohurl [3];
}

Example 2

The code is as follows:

/**
* Get the root domain name
* @ Param type $ domain name
* @ Return string returns the root domain name.
*/
Function GetUrlToDomain ($ domain ){
$ Re_domain = '';
$ Domain_postfix_cn_array = array ("com", "net", "org", "gov", "edu", "com.cn", "cn ");
$ Array_domain = explode (".", $ domain );
$ Array_num = count ($ array_domain)-1;
If ($ array_domain [$ array_num] = 'cn '){
If (in_array ($ array_domain [$ array_num-1], $ domain_postfix_cn_array )){
$ Re_domain = $ array_domain [$ array_num-2]. ".". $ array_domain [$ array_num-1]. ".". $ array_domain [$ array_num];
} Else {
$ Re_domain = $ array_domain [$ array_num-1]. ".". $ array_domain [$ array_num];
}
} Else {
$ Re_domain = $ array_domain [$ array_num-1]. ".". $ array_domain [$ array_num];
}
Return $ re_domain;
}

I hope this article will help you with php programming.