Handle errors from reddit

[Tokarak]

A 401 code is still an Ok(<...>) response, so the error handling was in the wrong place.

Hopefully the conditional logic (json["reason"] == "Unauthorized") is correct;

The information reported to the browser should be improved.

It's obvious that Libreddit wasn't designed with error-handling in mind.

Linked issue: #22

[Tokarak]

Draft until the efficacy and the correctness of the conditional logic (see above) is verified.

[sigaloid]

It's obvious that Libreddit wasn't designed with error-handling in mind.

😅 That's because we try to avoid logging at all costs to preserve privacy. Probably not ideal for cases like this. That's why I want to eventually add more debug-only logging so if there's a problem, someone can run it in debug mode for themselves

[Tokarak]

The error page is now a little more informative. It should probably be formatted better. I'm most worried about the privacy/security concerns for the host (the issue was there before): the status code and reason could be abducted, and an attacker could glean information from this error page.

[sigaloid]

I'm not sure how much of a vulnerability it is to have a user of the site know the status code returned from reddit - what kind of information would that leak?

[Tokarak]

Probably not a concern, but it can leak information that Reddit knows about the host which is unknown by the client. I was thinking information about the Reddit-facing network interface, but I doubt Reddit would leak anything about that.

A rationale is that the host is just a proxy for the client, and so everything Reddit sends should be forwarded to the client anyway.

[Tokarak]

Just confirmed working!

[sigaloid]

Sounds great, thanks! Merging.