Updating Semantic Models api - base64 encoded 'section' values are not json

[ddelapasse]

I've had some success pulling the semantic model via REST api and updating the name inside BUT I would like to update the LineageTags of the fields when I perform a 'clone' operation within my project (my project is a webapp that embeds powerbi).

I get the model content which is a list of section keys with base64 encoded values.  The issue is that when I decode those values I am not getting json - it's just strangely formatted text.  Is there some way to extract it in a different format so that it's easier to manipulate/update?  Below is an example of one table's section in the model.  Any advice?  TIA!

table ADR_Level1_2dd5567f-9c5e-4d5d-9608-1b565c2ab830

column ConfigTotal

dataType: string

sourceProviderType: nvarchar(max)

lineageTag: f298b532-ecdc-42ae-985b-298b825130db

summarizeBy: none

sourceColumn: ConfigTotal

annotation SummarizationSetBy = Automatic

column L1_CalDec01

dataType: double

sourceProviderType: decimal(18, 0)

lineageTag: dd5131fd-a7b7-4914-9707-f4f20aa52d2b

summarizeBy: none

sourceColumn: L1_CalDec01

annotation SummarizationSetBy = Automatic

column L1_CalText01

dataType: string

sourceProviderType: nvarchar(max)

lineageTag: 0df76d62-0309-41a6-bedd-8d1dcadc6eef

summarizeBy: none

sourceColumn: L1_CalText01

annotation SummarizationSetBy = Automatic

[ddelapasse]

This worked perfectly - I was scanning the help for 'json' and didn't realize that 'tmsl' was the same thing.  Thank you so much!!!

[ddelapasse]

Ah!  Thank you so much.  I will check into that.

[Deku · Accepted solution]

That is TMDL, bit like YAML for semantic model

Assume you use  Get Item Definition  Fabric API.

There is format part to the URL.

In the item definition it list formats as TMSL and TMDL

TMSL is the JSON version, so could try calling that. Should give you model.bim.

You can also use the C# libraries to convert between format