set httr user_agent

[wibeasley]

https://httr.r-lib.org/reference/user_agent.html

Following advice of httr vignette:

While we’re in this function, there’s one important header that you should set for every API wrapper: the user agent. The user agent is a string used to identify the client. This is most useful for the API owner as it allows them to see who is using the API. It’s also useful for you if you have a contact on the inside as it often makes it easier for them to pull your requests from their logs and see what’s going wrong. If you’re hitting a commercial API, this also makes it easier for internal R advocates to see how many people are using their API via R and hopefully assign more resources.

A good default for an R API package wrapper is to make it the URL to your GitHub repo:

I'm going to user just "OuhscBbmc/REDCapR" instead of the full "https://github.com/OuhscBbmc/REDCapR". I don't want any University's security team casually review the REDCapR code and wonder if it's contacting another server.