[Qgis-developer] release file after processing.runalg

[enrico chiaradia]

Hi Stefan, thanks again!
the file "map_to_clip.tif" is saved on the HD and it is not submitted to 
any process before executing the script (I know that because I can 
delete it before running the script).
At the same time, I noticed that the file "map_to_clip.tif.aux.xml" was 
created after running the script and closing qgis (absolutely, I did no 
other things!).
Can that suggest the process that locks the file?


Il 28/04/2017 11:00, Stefan Kiefer ha scritto:
> Hi Enrico,
> how is that file map_to_clip.tif created? There still could be a reference on that file, maybe because of the generation process (I assume that because you call it tempOutput, so there could be still a reference from another process). For example, if that file is visualized somewhere there definitly is a referene on that file.
>
> cheers
>
> Stefan
>
>> enrico chiaradia <enrico.chiaradia at yahoo.it> hat am 27. April 2017 um 16:29 geschrieben:
>>
>>
>> Hi Stefan and many thanks for your answer! but it seems not working :(
>> Here the new code. I replaced "tempOutput" with "output". Layer is
>> correctly loaded and removed but "tempOutput" cannot be deleted.
>>
>> import processing
>> import os
>>
>> tempOutput = 'D:/test_alg/map_to_clip.tif'
>> maskFN = 'D:/test_alg/mask.shp'
>> output = 'D:/test_alg/clipped_map.tif'
>>
>> algRes = processing.runalg("gdalogr:cliprasterbymasklayer",
>>                                           tempOutput,
>>                                           maskFN,
>> "-9999",False,False,False,5,4,75,6,1,False,0,False,"",
>>                                           output)
>>
>> try:
>>       # add to the map
>>       tempLay = QgsRasterLayer(output, "tempLay")
>>       if not tempLay.isValid(): raise Exception("Failed to load tempLay")
>>       QgsMapLayerRegistry.instance().addMapLayer(tempLay) #!!!!
>>
>>       layermap = QgsMapLayerRegistry.instance().mapLayers()
>>       for i, layer in layermap.iteritems():
>>         if layer.source() == output:
>>           print 'layername',layer.source()
>>           # Remove layer references
>>           QgsMapLayerRegistry.instance().removeMapLayer(layer.id()) #!!!!
>>
>>       # Delete the file
>>       os.remove(tempOutput)
>>
>> except Exception as e:
>>       print e
>>
>>
>>
>>
>> Il 27/04/2017 16:07, Stefan Kiefer ha scritto:
>>> Hi enrico,
>>> as far as I see from the reference you added the solution would be to add the result (resp. output) to a Layer instead "tempOutput". Then you remove that Layer, I suppose while removing the layer a reference on "tempOutput" ist released.
>>>
>>> cheers
>>>
>>> Stefan
>>>
>>>> enrico chiaradia <enrico.chiaradia at yahoo.it> hat am 27. April 2017 um 15:13 geschrieben:
>>>>
>>>>
>>>> Dear List,
>>>>
>>>> I'd like to remove an existing file (see [tempOutput]) after it was used
>>>> by a geoalgorithm. The geoalgorithm works perfectly but after its
>>>> execution, the file [tempOutput] is locked.
>>>>
>>>> Here a simple test script that returns "[Error 32] The process cannot
>>>> access the file because it is being used by another process:
>>>> 'D:/test_alg/map_to_clip.tif'":
>>>>
>>>> import processing
>>>> import os
>>>>
>>>> tempOutput = 'D:/test_alg/map_to_clip.tif'
>>>> maskFN = 'D:/test_alg/mask.shp'
>>>> output = 'D:/test_alg/clipped_map.tif'
>>>>
>>>> algRes = processing.runalg("gdalogr:cliprasterbymasklayer",
>>>>                                            tempOutput,
>>>>                                            maskFN,
>>>> "-9999",False,False,False,5,4,75,6,1,False,0,False,"",
>>>>                                            output)
>>>>
>>>> try:
>>>>        os.remove(tempOutput)
>>>> except Exception as e:
>>>>        print e
>>>>
>>>> I also found a solution on the web [1] but it doesn't work for me :( If
>>>> I understand correctly, the trick is to load the file as layer and then
>>>> release it. Here its implementation:
>>>>
>>>> import processing
>>>> import os
>>>>
>>>> tempOutput = 'D:/test_alg/map_to_clip.tif'
>>>> maskFN = 'D:/test_alg/mask.shp'
>>>> output = 'D:/test_alg/clipped_map.tif'
>>>>
>>>> algRes = processing.runalg("gdalogr:cliprasterbymasklayer",
>>>>                                            tempOutput,
>>>>                                            maskFN,
>>>> "-9999",False,False,False,5,4,75,6,1,False,0,False,"",
>>>>                                            output)
>>>>
>>>> try:
>>>>        # add to the map
>>>>        tempLay = QgsRasterLayer(tempOutput, "tempLay")
>>>>        if not tempLay.isValid(): raise Exception("Failed to load tempLay")
>>>>        QgsMapLayerRegistry.instance().addMapLayer(tempLay) #!!!!
>>>>
>>>>        layermap = QgsMapLayerRegistry.instance().mapLayers()
>>>>        for i, layer in layermap.iteritems():
>>>>          print 'layername',layer.source()
>>>>          if layer.source() == tempOutput:
>>>>            # Remove layer references
>>>>            QgsMapLayerRegistry.instance().removeMapLayer(layer.id()) #!!!!
>>>>            # Delete the file
>>>>            os.remove(tempOutput)
>>>>
>>>> except Exception as e:
>>>>        print e
>>>>
>>>> I didn't find any other solution for the moment. Any suggestion is
>>>> really very appreciate!
>>>>
>>>> Thanks
>>>>
>>>> enrico
>>>>
>>>>
>>>> [1]
>>>> https://gis.stackexchange.com/questions/93143/can-not-delete-file-after-using-runalg-function
>>>>
>>>>
>>>>
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