PI Web Services may be an option for you. If your platform can make SOAP calls in a standards based way you will be okay. We support both SOAP 1.1 and 1.2. For security, the WS-Security stack is supported, but may need some configuration depending on your needs. The out of the box installation is geared toward SOAP 1.2 with Windows security, but we provide sample configuration files for other scenarios.
Am I missing a trick or couldn't you do something like the following:
$comObjPi = new COM('PISDK.PISDK');
$server = $comObjPi->Servers->Item("YourPIServer");
$point = $server->PIPoints("SINUSOID");
The most important question would be:
Do you want to access the PI data on the server side (PHP) or on the client side (JS)?
If you want to use it on the server side, why not use PISDK (like Rhys mentioned). If you need it on the JS side, your best option would be PI WebServices. I don't think PI Webservices can be configured to use JSON, so you best bet would be to parse the XML in JS.
If you want to use PI Webservices in PHP(5), your best bet is the SoapClient, Example here
I get it, I'll look into COM or SOAP first.
Thanks all for the useful information.