This article contains PHP implementation of whois client (as a function ae_whois), which may be used to request domain information from specified whois servers.

Their method uses the socket functionality (fsockopen, fwrite, fclose) to make a connection to the remote server for the specified domain's information.

The other other two parts prepared you for this, the creation of the actual RSS file - correctly formatted and filled with data. They also include a simple feed reader so you can ensure your document can be read correctly.

Unfortunately, they chose to go with a long line of fwrites to push out each line of the file instead of pushing it all into one string and writing that. Using the multiples makes more work for the file handling and could result in a slowdown for a large amount of items in the RSS file.