Gateway

In addition to the core platform, an additional service (the “Gateway”) is available for external data collection. The architecture of this platform is engineered for compliance purposes. In our implementation, the core platform is deployed within the firewall of the Douglas. The Gateway, on the other hand, is deployed on a droplet accessible on the open internet.

When a clinical assigns an instrument to a subject, the Gateway receives a blob of data, including the subject ID, instrument structure, and a public key. The Gateway uses this data to generate a one-time link for the subject to complete the instrument. Once completed, this data is be encrypted using the public key and stored in the Gateway Database; the data cannot be encrypted without the private key, which remains within the Douglas firewall. Periodically, the Core API requests data from the Gateway, at which point it is decrypted and inserted into the Core Database and removed from the Gateway Database.

An assignment can be given a redirect URL when it is created, which must start with https://. Once the subject completes the assignment, the Gateway shows its completion screen for a few seconds and then sends them to that URL, for example back to the study portal they came from; a link on the completion screen lets them go straight away. A bulk operation applies one redirect URL to every assignment it creates. Without one, the subject stays on the completion screen.

The Gateway Database is a SQLite file kept in the sqlite volume. Each time the Gateway container starts, it brings that file up to date with the version being started, so upgrading the Gateway needs no manual database step.