Fix overriding the custom SoapClient class

[chyovev]

Hey,

in general all services extending the AbstractSoapClientBase class use PHP's default SoapClient class to handle requests, which is specified as a constant in the SoapClientInterface: DEFAULT_SOAP_CLIENT_CLASS.

As per documentation, a custom SoapClient class can be used by overriding said constant:

DEFAULT_SOAP_CLIENT_CLASS = '\SoapClient': this is the default SoapClient class that is used to send the request. Feel free to override it if you want to use another SoapClient class

However, simply overriding it does not work since the underlying SoapClient initialization method (initSoapClient()) relies on the value returned by the getSoapClientClassName() method which in turn reads the constant as a self::, i.e. as defined in the actual abstract class (or the interface in this case). Kind of like reading a private property inside a parent class – overriding in the child class has no effect.

If we use late static bindings on the other hand, it would read the constant's value from the extended class first, and then use the interface constant as a fallback: static:: instead of self::. Like turning a private property protected.

Currently, if my service extends the AbstractSoapClientBase class using all its functionality, but I decide to use a custom SoapClient, I would have to override the getSoapClientClassName() method in my service class. It would be easier if I could just specify it by overriding the DEFAULT_SOAP_CLIENT_CLASS constant – like the documentation suggests I should do 😊