ModbusServerContext doesn't implement __delitem__

[karlp]

ModbusServerContext implements getitem and setitem (Which is awesome by the way, it lets me add/remove/change slaves at runtime)

However, the only access to removing slaves is to leave the slave id, but set the slave object to None. This works, but you get errors like "pymodbus.server.async - Datastore unable to fulfill request: 'NoneType' object has no attribute 'validate'"

Wouldn't it be better if you could simply remove the slaves outright?

[karlp]

Actually, after reading more of http://docs.python.org/2/reference/datamodel.html#emulating-container-types, once delitem is done, it should be pretty easy to get full emulation of the container with that DictMixin.

It is also recommended that mappings provide the methods keys(), values(), items(), has_key(), get(), clear(), setdefault(), iterkeys(), itervalues(), iteritems(), pop(), popitem(), copy(), and update() behaving similar to those for Python’s standard dictionary objects. The UserDict module provides a DictMixin class to help create those methods from a base set of getitem(), setitem(), delitem(), and keys().

[bashwork]

I didn't know people were dynamically adding/removing slaves. I will gladly implement this.

[karlp]

I'm using this to simulate a network of modbus/RTU devices on a RS485 network, so I've got slaves added and removed, and with variable response time/failure rate per slave. I'll see if I can make the common bits a public project, it's all pyGObject based. pymodbus made it surprisingly easy to build up!