How to retrieve the Asset Blob Source URL given an asset id?

Scenario: I’ve got a schema with an asset field. Assets are stored on Azure Blob Storage. I’ve configured a webhook that executes when a content item based on that schema is updated.
The webhook only contains the asset id:

"asset": {
  "iv": [

But I need the name of the Blob in Azure Blob Storage, as I need to update metadata there.

I’ve seen this topic, explaining I can use GraphQL. But I don’t think I can use GraphQL directly on assets? I can’t query on my content, as I need to cater for the scenario that the asset field is changed.
The “dataOld” contains the old asset id, so I need to query directly on asset id, I can’t query on my content type.

When I call the API at /api/apps/{app_name}/assets/{id} it returns a bunch of metadata, but not the sourceUrl.

The graphql endpoint should provide a sourceUrl field for each asset. You can resolve assets in graphql as well.

But if you have the id you can also determinate the blob source url. I am not sure how the asset blob storage urls are formatted, but the id is just the path to the asset.

Thanks @Sebastian for your prompt reply.
Just checked, the name of the blob seems to be {id}_0 , so _0 appended to the ID. Will try that, doing some more testing now.