Replace user_agent_string with a random string

[tobiasknudsen]

Fixes #44

It looks like Medtronic has added some rate limiting based on the User-Agent on the login endpoints, since they return 502 Too Many Connections Requests in 10 minutes. Hardcoding the User-Agent to a real User-Agent fixes it, but also just sending a random string seems to work for me.

Not sure how ideal this fix is

[bewest]

Thanks for the experimentation and this insight. I wonder if it would help to use another header, purely to provide a random number for traceability. For example, if we also send x-traceable-req: uuid4 or similar. This way, if they perform rate limiting against a serialized form of the request, they can correctly trace user agents while essentially deduping our requests?

[bewest]

FWIW, there's a new module, nightscout-connect, with a similar feature discussed here: nightscout/nightscout-connect#19. Nightscout Connect is a bit easier to maintain because 7 vendor libraries can share a single HTTP dependency for Nightscout. It would be great to experiment to see if just 6 - 8 random characters is enough, in addition to strings to correctly attribute the software to our open source projects.

[tobiasknudsen]

Looks like they are targetting "nightscout" in the User agent, just removing it also works...
[software.name, software.version, software.bugs.url].join(' // ').replaceAll("nightscout", "")

[bewest]

Thanks for testing @tobiasknudsen. I can confirm any trace of nightscout on European servers will result in a rejected request. However, it works fine for patients in the United States. I think it's critical to contact regulators to let them know of these digital rights abuses and attempts to generate plausible deniability. Is legal for Medtronic to block patients from accessing factual information about themselves?

Perhaps we can stick some attribution for NS in another header.