2011/11/5 Jocelyn Jaubert <jocelyn.jaubert@...>:
> Le 30 octobre 2011, Guilhem Bonnefille a écrit :
>> Technically, current viking try to use an If-modified HTTP header
>> flag. But the check can be done many times per minutes. We plan to
>> extend this timeout. As suggested, we will use the 7 days timeout you
>> require for OpenStreetMap servers.
> Note that openstreetmap.org doesn't use If-modified HTTP header, but
> Etag header. Etag headers support was added to viking only a year ago,
> which might explain why there are too much traffic from viking.
Oops... you're right, it's ETag feature.
> I have just looked at git log, and the first version which has Etag
> support is 0.9.96. According to the summary available from
> http://ikaria.informatik.uni-rostock.de/mm337/osm/tile_stats/, versions
> before 0.9.96 account to 1/4 of all viking requests.
> It is not possible from the summary to know if there are some viking
> clients that generate too much traffic, or if it is evenly spreaded
> between the clients.
Furthermore, I'm not able to understand if the data report number of
hits or amount of data. With ETag feature, viking regularly request
tiles, but no data are sent back. This certainly produce a load on
server, but a lightweight traffic on network.
Perhaps Matthias can give us more details.
> Anyway, I've looked at the modifications from my initial commit to the
> latest version, and it looks like Etag should still work as intended.
> But I didn't check if the network traffic sends the correct Etag value
> to the server when checking if there is a new tile.
> Can anybody check this ?
I did the following test:
1) launch viking in debug and verbose (viking -d -V)
2) download tiles
3) right click on map entry and "Download New Onscreen Map"
In the log, I can see the ETag was sent and the response from the
server indicates that Etag was considered and no data was transmitted.
All seems OK.
-=- JID: guyou@... MSN: guilhem_bonnefille@...