[Qgis-developer] strange GetCapabilities caching

[Jeff McKenna]

Hi Nicklas,

Just a heads up that this is still an issue with 2.16.0; however now it 
seems to be even worse now:

  - the "Clear" button for clearing the cache has now been changed to an 
icon with arrows, that is confusing to the user.  I think a button with 
the words "Clear Cache" makes more sense.
  - I just now spent 4 hours trying to get a service to appear in QGIS, 
and the issue was that pressing the clear cache icon in QGIS 2.16.0 
wasn't actually clearing the cache: I had to go into 
C:/Users/Jeff/.qgis/cache/data7/ and manually delete the contents of 
that folder, and magically my WMS service worked in QGIS

Keep your heads up for that issue.

-jeff



-- 
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/

On 2016-03-28 3:16 PM, Nicklas Avén wrote:
> Hallo all
>
> First, Thanks a lot for QGIS and QGIS Server. It is  amazing software.
>
> But now I have had a very frustrating problem for the last 5 hours.
>
> After setting up a working QGIS server a few weeks ago, I now returned
> to see everything working after some major refactoring at the database.
>
> Nothing worked, and after some hours I started to get really frustrated
> since we have just a few weeks until we go in production and I really
> don't want to replace QGIS Server because of unpredictable behavior.
>
> The error I had was:
> Invalid Layer: WMS provider Cannot calculate extent Raster layer
> Provider is not valid (provider: wms, URI:
> contextualWMSLegend=0&crs=EPSG:4326&dpiMode=7&featureCount=10 ...
>
> on all layers but one.
>
> I saw this question was asked several times at the net, but no one
> seemed to have had any answer:
> https://hub.qgis.org/issues/10634
> https://hub.qgis.org/issues/7712
> http://osgeo-org.1560.x6.nabble.com/qgisserver-problem-td5095165.html
>
>
> The last link solved it by a fresh install and now I understand why.
>
> Finally I found the answer
> http://osgeo-org.1560.x6.nabble.com/WMS-provider-Cannot-calculate-extent-td5250516.html
>
> But the OP didn't get an answer of his follow up question: Why the h...
> is the GetCapabilities cached?
>
> I ask the same thing, especially since a new version of GetCapabilities
> is also fetched.
>
> This is what made me use 5 hours on debugging (including turning the
> server inside out, both database and uwsgi, nginx and so on).
>
> The layers presented when connecting to the wms server was fresh and
> new. But it seems like, when I tried to add the layer it used a cached
> GetCapabilities, which didn't correspond to my new setup on the server.
>
> I could also sniff the GetCapabilities request. But I also saw that no
> request was made when I tried to add the layer. So, now when I see the
> whole picture I look rather stupid, but I couldn't imagine that I had
> fresh data when connecting, but old data when trying to add the map.
>
> Another thing that made things bad was the error message just flashing
> on the top of my map. It didn't write anything to the log windows from
> what I could see, and the message was shown in a too thin box. So I had
> to try to add the layer, quickly close the "Add WMS window" and copy the
> text in the too thin box to be able to read it.
>
> Sorry for my frustrated tone. I still really love QGIS. But software
> (any software) can drive you crazy sometimes.
>
> I also suspect that I might get into exactly the same trap after a few
> months when i have forgotten this. I hope I find this mail then on my
> googling :-)
>
> Regards
>
> Nicklas Avén
>
>