[Qgis-developer] WFS-alike plugin with caching: approach? (Was WFS still fetches everything)

[Stefan Keller]

Hi,

I'd like to enhance a WFS-alike Python plugin with caching.
Currently it simply creates a vector layer and attaches a REST
webservice on it which returns GeoJSON.
>From this time, the layer is not controlled anymore by the plugin and
reloads everytime the layer get's zoomed/panned or after QGIS project
is re-opened.
Now I'd like to refactor it and get more control over the layer and
implement caching.
1. What would be the best approach to implement the caching ? With a temp file?
2. How to tell QGIS after reloading the project, that the plugin is
needed (on a different machine or in case the plugin got
de-installed)?

Cheers, S.


2015-03-26 18:17 GMT+01:00 Marco Hugentobler <marco.hugentobler at sourcepole.ch>:
> Hi Giovanni
>
> Unchecking the option 'cache features' did exactly that (first fetch based
> on current view extent and refetching of new parts when panning). This seems
> broken now (maybe since the multithreaded rendering?).
>
> Another (not so convenient) method is to create an ogc filter by double
> clicking on the 'filter' column (enter ogc filter xml as a string in the
> expression editor).
>
> Regards,
> Marco
>
>
> On 26.03.2015 16:11, G. Allegri wrote:
>
> Hi,
> you probably read the question from Peter on qgis-user [1].
> Five years ago Marco said that this behaviour should have been changed
> (first fetch based on current view extent) but AFAICS the WFS provider still
> behaves the old way.
> Was this proposal discarded for some reason?
>
> Giovanni
>
> [1]http://lists.osgeo.org/pipermail/qgis-user/2015-March/031354.html
> [2] http://hub.qgis.org/issues/1421#note-4
> --
> Giovanni Allegri
> http://about.me/giovanniallegri
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> Dr. Marco Hugentobler
> Sourcepole -  Linux & Open Source Solutions
> Weberstrasse 5, CH-8004 Zürich, Switzerland
> marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
> Technical Advisor QGIS Project Steering Committee
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