Developing "virtual domain Name" system with PHP programming _php

If your own server can also implement the précis-writers domain name is good. Actually, it's not complicated. You can also make a précis-writers domain Name System.

The key technology of the précis-writers domain Name system is to implement Web page redirection (redirctory). In essence, Jane
The domain Name system and the virtual machine system are completely different. The virtual domain name and IP of the virtual machine have a one by one correspondence relationship. The précis-writers domain Name system does not need to do one by one mapping of domain names and IPs. In other words, it does not require complex domain name resolution mechanisms and virtual machines to complete, and what it does is to redirect your browser to the place where you originally stored the HTML page when you requested Yourname.somedomain.

The operating environment of this program is: RedHat 5.1 Linux under the Apache1.3.6 Web server +php3 language. Before we write the program, we need to set up our server first. The first thing to do is to have Apache server support PHP3. To ftp.redhat.com download mod_php-2.0.1-9.i386.rpm, after installation, modify the/etc/httpd/conf/http.conf file, remove #loadmodule php3_module a line in front of the # comment number, Also in the/etc/httpd/conf/srm.conf file to remove #addtype application/x-httpd-php3. php3 the previous comment number, and add DirectoryIndex after index.php3. Restart Apache server, where the server supports the standard PHP3 language script file and can use INDEX.PHP3 as the default home page.

Set up the DNS server so that it can resolve the pan domain name. General UNIX and Linux system DNS resolution is done by the bind daemon, Bind4 and Bind8 configuration Files/etc/named.boot and name.conf, respectively, configured according to your system modification. Set the Bind profile/etc/named.boot, add a new domain record by adding the phrase "primary domain.com db.domain". Add in/etc/name.conf:

Zone "domain.com" {

Type master;

File "Db.domain"; };

Create a new master domain record file Db.domain in/var/name/in the following format:

N SOA dns.domain.com root.domain.com (

199811291; Serial

28800; refresh.

7200; retry

604800; expire

86400); minimum

Dns

MX Ten dns.domain.com.

DNS A 202.115.135.50

www A 202.115.135.50

* A 202.115.135.50

The key is the last sentence, all hostname that are likely to appear in the entire domain are pointing to the same IP. Execute/USR/SBIN/NDC Reload and reload the domain name database. Test, you should casually ping a domain host (except the marked), pointing to the specified IP, then the DNS server settings are complete.

The final step is to compile the PHP3 script. We have just explained the whole principle in detail in the diagram, so it is not very difficult to write a redirected program.

Let's look at a complete HTTP header message sent by IE5.0:

Accept:application/vnd.ms-excel, Application/msword, Application/vnd.ms-powerpoint,image/gif, Image/x-xbitmap, Image/jpeg, Image/pjpeg, */*

Accept-encoding:gzip, deflate

Accept-language:zh-cn

Connection:keep-alive

Host:ww.yahoo.com

user-agent:mozilla/4.0 (compatible; MSIE 5.0b1; Windows 98)

We need to remove the host information from the entire HTTP header, and then separate the first part of the http://www.jj.jx.cn/www.xxx.xxx/default.htm form, "www", which is the hostname (also known as the user registered name). As the keyword for the redirect retrieval.

After retrieving the URL information of the user registration, we send a redirect command "localtion:http://www.jj.jx.cn/somewhere/sample.html" to the user's browser to redirect the user to the specified page.

In PHP3, there is a function getallheader () to get the HTTP header information sent by the browser. We mainly need to use this function to complete the program.

Attached to the source program, because only experimental nature, so in the query user information, not using the database, if the whole system to actual application, it must be connected with the database, or query user information process will be very long, greatly affect the efficiency, and user data management is not convenient.

In the source program, all user information is recorded in the Data subdirectory under the User.dat file. The format is:

Username

Http://octopus.cdit.edu.cn/~qap213/index.html

Attached PHP3 source program:


Get HTTP ' s Header and parse it//

= Getallheaders ();

while (list (,) = each ()) {

if (= = "Host") {= Strtok (, ".");}}

Jump out the Banner ' s window//

Echo ';

Seek the user information from the recorded file//

if (!=file ("Data/user.dat")) {echo "Open data File error!!";}

= "http://";

for (=0;
if (Strtok (, ":") = =) {

=;}

if (= = "http://") {echo "not found the uesrname of data!";}

else{

Echo ' 