[gdal-dev] Write dataset to web output

[Guillaume Sueur]

Hi Even,

Sorry, I'm only noticing your reply now.
My use case is weird as I am using GDAL to reproject a WMS source which 
doesn't offer web mercator (French Cadastral Parcels WMS) and needs some 
computation on the URL (city code, CRS depending on location).
If I understand your solution, I can't directly output my datasource to 
the webserver, I need to write it on disk first ?

All the best

Guillaume

Le 26/09/13 01:19, Even Rouault a écrit :
> Le mercredi 25 septembre 2013 10:48:00, Guillaume Sueur a écrit :
>> Hi list,
>>
>> I've build a python gdal script which retrieves WMS images from a remote
>> layer. I'd like to send the image back to the browser, but I can't
>> figure out how to do that...
>> Once I've got a correct gdal dataset, how to read it into the server
>> response ?
>
> Guillaume,
>
> Not sure to completely understand your use case, but why not just using
> OpenLayers to display images from a WMS source ?
>
> If you want to stick with your script, a solution could be to create a PNG file
> from the GDAL dataset ( gdal.GetDriverByName('PNG').CreateCopy('the.png',
> src_ds) ) and then dump it to the standard output of your webserver after
> having written a "ContentType: image/png\n\n" header.
>
> Note : you can do that without having to create a file on the regular
> filesystem, but by CreateCopy'ing() instead to /vsimem/the.png and using
> gdal.VSIFOpenL() / gdal.VSIFReadL() / gdal.VSIFCloseL() to get the content
> into a Python buffer object ( see autotest/gcore/vsifile.py in GDAL source tree
> )
>
> Even
>