If you have a web server and you want to check periodically if it didn’t crash again. Just create a PHP script, open a socket to the server with fsockopen() function, and wait. After the time specified in the $timeout parameter has elapsed, you know if the server is online or offline.
PHP can communicate with other servers using sockets. Sockets allow data exchange between processes on the same or different servers. PHP uses the fsockopen() function to open a socket connection to a web server.
As mentioned previously, current Web Services almost always use WSDL (Web Services Description Language) to describe the operations and parameters of your service. Writing WSDL files manually is a real pain and error-prone, but most serious Web Services implementations for PHP can automatically create WSDL.
How to create a SOAP service in PHP. You will write code in two files: a server file and a client file. The server file defines the functions that the service can perform, and the client file calls those functions and displays the results.
A web service is an interfaceless application that can be called to process information. In PHP, a web service can provide the functionality remotely on a web server.
How to validate XML and HTML files (or strings) with PHP’s DOMDocument class.
How to use libxml extension to handle errors while parsing XML string or file.
With SAX Parser, you create functions to deal with specific events, for example, the start or end of an XML element (tag). When the parser encounters an XML element, it calls the event handler functions to process that element.
How to transform an XML document and an XSL stylesheet using XSLT and capture the results.
Learn how to use DOM to read all elements in the XML file and outputs them. Also how to append data to an XML file (or create a new XML file if not already exists).