danielctull-forks / covid-19-app-ios-beta

Source code of the Beta of the NHS COVID-19 iOS app

NHS COVID-19 BETA for iOS

This application runs in the background and identifies other people running the app within the local area by using low energy Bluetooth. While the app is running permanently in the background, it periodically broadcasts and listens for other Bluetooth-enabled devices (iOS and Android at this time) that also broadcast the same unique identifier.

How it works

Our unique identifier is also known as our service characteristic. In the Bluetooth spec, devices can broadcast the availability of services. Each service can have multiple characteristics. We use a characteristic to uniquely identify our service and distinguish from all other sorts of Bluetooth devices.

For every device we find with a matching characteristic, we record an identifier for the device we saw, the timestamp, and the RSSI of the Bluetooth signal, which will allow a team later on to determine who was in close proximity to individuals infected with the novel coronavirus.

Functionality

• Passively collect anonymized ids of other users of the app that the device has been in proximity with (stored locally on the device)
• Allow the user to submit their "contact events" to NHS servers
• Receive push notifications from NHS and inform the user of their exposure status

Development

Setup

cp Sonar/Environments/Sonar.xcconfig.sample .secret/Sonar.xcconfig
./bin/make-environment < Sonar/Environments/environment.json > .secret/Environment.swift

• Fill in the Environment.swift file with the appropriate values from another developer.
• Get a copy of GoogleService-Info.plist from one of the other developers and copy that into the .secret directory.
• If Xcode is open, restart Xcode. Xcode does not handle configuration files being changed out from under it gracefully.

Notifications

The app currently relies on remote (as opposed to push) notifications, which we unfortunately have not been able to trigger on the Simulator. Push notifications (in the form of .apns files) can be dragged onto a Simulator window or passed into simctl, but remote notifications are only delivered on devices.

There are currently a couple of ways to do development with remote notifications:

• ./bin/pu.sh is a script forked from pu.sh. There are instructions there for obtaining credentials from an Apple Developer account. However, we are out of available APN keys, so you'll need to obtain that from another developer. Run the script with the path to one of the example notifications to send a remote notification through Apple: ./bin/pu.sh "Example Notifications/2_potential_diagnosis.apns. You will also need to set the following environment variables to configure the script:
  • TEAMID
  • KEYID
  • SECRET - the fully expanded path to the .p8 key.
  • BUNDLEID
  • DEVICETOKEN - retrieved from the console when running the application.

Releases

Builds are automatically generated from CI. Each two hours, we merge any changes from master into internal, bump the version, and cut a build that gets uploaded to Test Flight.

Please do not merge the internal branch or ci branch into master.