Dear R-devel, For a project of mine which aims to improve R package distribution and routing, I came across the fact that the treatment of the User Agent info alongside download requests is not consistent. `?download.file` explains this in detail, so I?ll assume this info to be know and just quote the most important bit:
The default is "R (version platform arch os)" except when ??libcurl?? is used when it is "libcurl/version" for the ??libcurl?? version in use.
My question is:
Why is that? And why is the value of `getOption("HTTPUserAgent?)` not
being sent consistently alongside all http(s) requests? Right now, it
differs by OS and download method.
In my specific use case, `getOption("HTTPUserAgent?)` would contain
some OS information that could be used for dynamic routing of requests.
Right now, this works for some environments (e.g. most Linux
distributions), however, on others, (e.g. macOS), only ?libcurl
<version>? is sent, even though `HTTPUserAgent` is defined as an
option.
Aside from my specific use case, I?d argue that sending an informative
User Agent is a gentle way to identify oneself when making a request.
The current content of the User Agent info on each platform is again a
different topic, but for now I would just like to get some feedback on
the topic of sending it in the first place.
Best
Patrick