Hi
In my opinion, it is better to use the Qt classes for the network
requests than curl. In QGIS, we have QgsNetworkAccessManager, which
picks up automatically the network settings from the options tab (proxy
settings, exclusion list, password, disk cache). It has nice progress
reporting by signal/slot, the possibility to interrupt the network
request and a disk cache. And the possibility to provide custom
implementations for all that if necessary.
Like this, WFS, WPS, WMS providers, plugin installer and open layers
plugin (and third party python plugins) have a unified method to do
network requests. No need to use a different network library for each
one (and the mapping is never 1:1, there is always loss).
So while it might be quicker (in terms of development time) to use the
GDAL provider, a standalone provider is always more native and flexible
(that's also the reason there are QGIS vector providers for postgres,
wfs, gpx, spatialite, grass while everything can be read with the OGR
provider).
Regards,
Marco
Am 12.07.2012 15:51, schrieb Even Rouault:
Yes - Radim already made a first pass implementation using GDAL WCS
though he said there were some problems with it - I think the most
critical being that it doesn't support proxy access (I am speaking
under correction here as I haven't looked into it in that much detail
myself).
This should be rather easy to add. It is just a matter of setting the right
option to CPLHTTPFetch() (and thus the curl library), namely :
<li>PROXY=val, to make requests go through a proxy server, where val is of the
form proxy.server.com:port_number
<li>PROXYUSERPWD=val, where val is of the form username:password
Note: They can also already be used by setting the GDAL_HTTP_PROXY and
GDAL_HTTP_PROXYUSERPWD configuration options/environmenet variable, which will
act on all GDAL/OGR drivers that go through the CPLHTTPFetch() function.
I see Radim is already a GDAL committer, so there shouldn't be too much overhead
if he wants to hack in the WCS driver.
I will let Radim comment on any other issues. I think from
the project perspective we don't mind too much which approach is used
if the result is efficient and integrates nicely into QGIS.
Regards
Tim
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