#295 Add mapping for value for RestAPI

[ArndGerns]

Added mapping for value for RestAPI

It is now possible to have a mapping for read and write for a rest api datapoint.

Example:

<valueMapping>
  <mapping>
    <from>off</from>
    <to>false</to>
  </mapping>
  <mapping>
    <from>on</from>
    <to>true</to>
  </mapping>
</valueMapping>

For a write data call, the generic value is mapped with the mapping and the mapped value is written to the rest api.

For a read data call, the value is read from the rest api and then mapped to the generic value.

[ergo-furrer]

@ArndGerns @mkrebs81 : OK, for me.

[mkrebs81]

I believe this will be sufficient.

The REST API query string or parameters are strings anyway. And the "from" content should be parsable according to the data point's data type.

I suppose the conversion direction depends on whether it is a read or write operation:

• read --> from = value returned by REST call, to = value returned to communicator
• write --> from = value given by communicator, to = value given to REST call

[ergo-furrer]

I believe this will be sufficient.

The REST API query string or parameters are strings anyway. And the "from" content should be parsable according to the data point's data type.

I suppose the conversion direction depends on whether it is a read or write operation:

• read --> from = value returned by REST call, to = value returned to communicator
• write --> from = value given by communicator, to = value given to REST call

It's my understanding too.

[ArndGerns]

Then it seems to be ambiguous. I guess @ergo-furrer has understood it differently.

Can we rename the mapping values in

• <restValue> => the value in the rest API call
• <jsonValue> => the value in the generic inferface

That would be unambiguous. What do you think? Better names?

[ergo-furrer]

Then it seems to be ambiguous. I guess @ergo-furrer has understood it differently.

Can we rename the mapping values in

• <restValue> => the value in the rest API call
• <jsonValue> => the value in the generic inferface

That would be unambiguous. What do you think? Better names?

What about <genericValue>, <deviceValue> ?

[ArndGerns]

Then it seems to be ambiguous. I guess @ergo-furrer has understood it differently. Can we rename the mapping values in

• <restValue> => the value in the rest API call
• <jsonValue> => the value in the generic inferface

That would be unambiguous. What do you think? Better names?

What about <genericValue>, <deviceValue> ?

Yes. Better.

[ArndGerns]

Have changed it now to <genericValue>, <deviceValue>. If it is ok, I'ld merge it.