Do we really have to build our own Digital Downloads App to be able to manage creating orders via API (i.e. transferring orders from another platform) or more general situation - to do anything related with downloadable products that requires API calls?
Orders created via API don't contain a download link even it has a downloadable product. Digital Downloads App is apparently / normally managing its own data source that is linking with orders and creating the URLs for each order entity instead of basically creating the links on the fly by looking at the order line items and verifying the downloadable product in that order on demand - in the checkout or order status page.
Or perhaps Digital Downloads App could have a trigger that will create the download URL / associated data in its own data source when an order is created (even via API) contains a downloadable product?
It is a good project, Digital Downloads App, however it really needs to be merged into the Shopify core application instead being an App. Downloadable products is really a requirement, not something rare.
Or, please, at least publish the API that we can access / manage the associated data.