it would be great of to have a function or solution to get rid of the fixed URL's but use relative paths. We use https://server/indicium/iam/appl_id/process_attachment(key_id=1,attachment_id=50)/MODEL.download_file_upload(file_id=null) to get images to show in HTML.. but the same applies for the use of HTTP connectors to get things from your own application. There is not good way now to set it up one and for it to work in different environments.
I would like to see a solution that we can use in the model and code a function or something like tsf_user to get the base URL that will always match the runtime environment.