transferSpec contains all of the specifications that you define for your transfer. These specs are passed to the server which uses them for generating the return JSON that allows the action to take place. Below are some examples of the most commonly used setups. For a list of all possible values please see the API docs.
For security reasons, source paths submitted to the Connect API for upload transfers (AW4.Connect#startTransfer) must be obtained either using the showSelectFileDialog/showSelectFolderDialogcalls or setDragDropTargets calls. That's the way to make sure that users are aware of the transfer happening between their host and the remote server.
Similarly, destination paths for downloads must follow the same approach if they are absolute paths (ie. if "use_absolute_destination_path" is set to true in connect_spec JSON).
Note: Aspera Connect does not have an
overwrite boolean-type option (which would allow the user to change the overwrite policy), because each new transfer request overwrites the pre-existing files by default. However, you can back up existing files before they are overwritten; add the value,
"save-before-overwrite": true to the JSON for the
transferSpec before starting the transfer. See Preserving Existing Files Before Download for additional details.