Suggestion for improved error message.

[haertig]

Suggestion for improved error message:

Current error message:

Failed to load books from calibre library, with error:
Failed to communicate with "/calibre/interface-data/books-init?library_id=calibre&sort=author_sort.asc%2Cser ies.asc&1518410374056", network error, is the server running and accessible?

How about adding the details needed to troubleshoot? For the above error (in my example), the root cause was "No route to host". I had to use "curl" on the URL (as opposed to a web browser) to find out what the problem was so I could troubleshoot.

The URL was:

 h t t p s://my.domain.net/calibre/#panel=book_list&sort=author_sort.asc,series.asc

BTW, does anyone know what would cause an intermittent "No route to host" problem? Things will be working fine, then all of a sudden, bam, I start getting this error. If I restart the nginx webserver that is fronting calibre-server, then this usually, but not always fixes it. For a while. Then the error reappears. It seems like if I restart calibre-server, then I also have to restart nginx. That fixes it 95% of the time (for a while, then it dies again). But 5% of the time, restarting everything fails to correct the problem. Then at some time in the future I restart things again and all is good again. I'm thinking this is some kind of nginx problem. Not sure. Need to troubleshoot some more. Note that when I am getting the "No route to host" error, then I can go directly to calibre-server at it's local address on port 8080 and get in just fine. So the issue does not appear to be in Calibre (nor would I expect Calibre to be able to create this error even if it wanted to - this is network/routing, not application).

This problem intermittently appears, but it does not intermittently disappear. Once it appears, it looks to be a permanent failure ... until I start restarting things again.

[edit]
Wait, ... hold the phone. Additional information incoming. When I am getting the error, if I go into my web browser and clear ALL content stored locally by calibre-server (cookies, application cache, database storage, local storage, etc.) and try again, after a timeout the browser times out with the following error:

This site can’t be reached
h t t p s://my.domain.net/calibre/#panel=book_list&sort=author_sort.asc,series.asc is unreachable.
ERR_ADDRESS_UNREACHABLE

That's a more useful error message (it's coming form the browser, not the local data that calibre-server stored).

Then, miraculously after a few seconds of displaying this error message (which I would think would have been permanent) it continues on, all by itself with no other action by me, and successfully accesses the calibre-server website. An automatic reload or something like that.

Now I am totally confused. I have no idea what is going on.

[kovidgoyal]

I know of no way to get detailed information on underlying causes of network errors in javascript. If you do, patches are welcome, the relevant function is ajax() in ajax.pyj