[Tilesathome] Info on t at h server changes

[spaetz]

Hi all, this is a summary of the changes that I have been performing in the t at h server. They are FYI and don't require client intervention, so feel free to ignore them if you are not interested.

1) The rerequest URI is using HTTP POST, rather than HTTP GET and uses your client authentication. Unfortunately there was a  bug in the client that prevented this from working. That is fixed as of r9484 (from today), clients should auto-update. I have tried it and it works now. So in case of an error, the job should really go back to the server, let me know if you notice odditites.

2) Shiny new user statistics for each user linked from wherever a user name appears. Besides the info that you already have (uploaded tiles and kb), it shows the current active (ie rendering) requests that are assigned to you. This should match the number of clients that you have running, now that the rerequest thing works again.
Long term, I'll add things like: last 20 uploaded tiles for this user (should make spotting broken clients easier)

3) The next bottleneck is the t at h API, there are often long queues with clients waiting for data. I see 2 solutions for that (3 actually), most out of the scope of t at h:
 - There are 5 new boxes for OSM and some are supposed to run the API, it would be great if t at h could get an additional API slot or 2.
 - OSMXAPI will probably move from the t at h server box to a box of it's own, we can then use it as our fallback again.
 - the client could fetch data depending on the priority of the rendering from a different source, e.g. all those automatic renderings because of changed tiles could use OSMXAPI (which is 6 minutes behind the real data), while interactive priority 1 renderings could query the "real" API.

4) Next steps in the t at h server development will be a machine-queryable request status API (is 12/234/543 just rendering and how old is it?), and server logging that enables me to easier spot broken clients (who is handing back requests and for what reasons) as well as other serious errors.

Thanks for listening, open for feedback and suggestions as always
spaetz