Python Data Layer scopes

[criss07]

Hi all.

In this example is shown how to create a Data Layer scope for a specific node written in C++: How-to-provide-API-in-the-Data-Layer-for-your-app .

Is there a way to do the exact thing but in Python? I could not find the CreateScopeDirect method in python.

Thank you,

Criss.

[nickH]

Hi Criss, 

Yes. You can do the same thing also in Python. Therefor import the "Scope.py" from ctrlx-automation-sdk/src/python/comm/datalayer/Scope.py. 

Working with Flatbuffers in Python is a little bit different to C++. If you are struggling with that, I can recommend you to take a look at the documentaion from google. 

Best regards,

Nick

[criss07]

Thank you for the hint. I was able to write down some code but it still does not work.

    builder = flatbuffers.Builder(0)
    permissionsRW = builder.CreateString("test-node/**")
    description = builder.CreateString("Allow to read and write")
    name = builder.CreateString("Test-node RW permission")
    identifier = builder.CreateString("datalayer.test-node.rw")
    Scope.ScopeStart(builder)
    Scope.AddPermissionsRw(builder, permissionsRW)
    Scope.AddDescription(builder, description)
    Scope.AddName(builder, name)
    Scope.AddIdentifier(builder, identifier)
    scope = Scope.ScopeEnd(builder)
    builder.Finish(scope)
    variant = Variant()
    variant_result = variant.set_flatbuffers(builder.Output())
    if variant_result is not Result.OK:
        print("ERROR: creating variant flatbuffer: ", variant_result, flush=True)
    result, var= client.create_sync("datalayer/security/scopes", variant)
    if result is not Result.OK:
        print("ERROR: create scope failed: ", result, flush=True)

I receive the error : ERROR: create scope failed: Result.TYPE_MISMATCH. It seems like the variant type is wrong maybe? I don't know why.

[nickH · Accepted solution]

Hi Chriss, 

If you take a closer look into the Scope.py you can see, that the permissions in this Flatbuffer are not Strings but Vector of Strings. Here is how I got it working. 

            builder = flatbuffers.Builder(1024)
            permissionsRW = builder.CreateString('test-node/**')
            Scope.StartPermissionsRwVector(builder, 1)
            builder.PrependSOffsetTRelative(permissionsRW)
            permissionsRWVector = builder.EndVector()
            description = builder.CreateString("Allow to read and write")
            name = builder.CreateString("Test-node RW permission")
            identifier = builder.CreateString("datalayer.test-node.rw")

            Scope.ScopeStart(builder)
            Scope.ScopeAddIdentifier(builder, identifier)
            Scope.ScopeAddName(builder, name)
            Scope.ScopeAddDescription(builder, description)
            Scope.ScopeAddPermissionsRw(builder, permissionsRWVector)
   
            scope = Scope.ScopeEnd(builder)
            builder.Finish(scope)

            variant = Variant()
            variant_result = variant.set_flatbuffers(builder.Output())
            if variant_result is not Result.OK:
                print("ERROR: creating variant flatbuffer: ", variant_result, flush=True)
            result, var= datalayer_client.create_sync("datalayer/security/scopes", variant)
            if result is not Result.OK:
                print("ERROR: create scope failed: ", result, flush=True)

Best regards, 

Nick