[MapProxy] Image processing error

[David Pavlíček]

I have finally resolved this issue. It was caused by our http proxy which
adds accept-encoding:gzip to all requests. Thus all images were gziped and
not readable by PIL.

Some libraries can handle this by checking incoming headers and then
decompress content if necessary. But this is not case of urllib2 used by
mapproxy.

So, make sure that your http proxy behaves as expected!

Best regards David



út 6. 11. 2018 15:08 odesílatel David Pavlíček <pavlicek.david at gmail.com>
napsal:

> I didn't think so...
>
> http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer?request=GetCapabilities&service=WMS
> is working as expected. Also getmap request from debug session is working
> properly... There must be another issue...
>
>
> út 6. 11. 2018 v 14:51 odesílatel Lukas Macur <lukas.macur at gmail.com>
> napsal:
>
>> Hello, I believe the problem is on source site, that is not working
>> http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer
>> http://mpp.praha.eu
>> <http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer> - is
>> working, but the arcgis server services are not ok (
>> http://mpp.praha.eu/arcgis/services
>> <http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer>).
>>
>> Regards,
>> LM
>>
>>
>> út 6. 11. 2018 v 13:42 odesílatel David Pavlíček <
>> pavlicek.david at gmail.com> napsal:
>>
>>> Hi,
>>> did you solve that Issue? I'm experiencing pretty much the same problem.
>>> Our MapProxy yesterday starts to respond with: "error while processing
>>> image file: cannot identify image file <mapproxy.image.ReadBufWrapper
>>> object at 0x7f67d86e6c10>
>>>
>>> I reduce the config to simplest one possible, but with no luck. Error is
>>> still there. Our config is as follows:
>>>
>>> services:
>>>   demo:
>>>   wms:
>>>     srs: ['EPSG:5514']
>>> sources:
>>>   dtm_praha:
>>>     type: wms
>>>     req:
>>>       url:
>>> http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer?
>>>       transparent: true
>>>       layers: 0,1,2,3
>>>
>>> layers:
>>>   - name: DTMP
>>>     title: DTMP
>>>     sources: [dtm_praha]
>>> globals:
>>>   image:
>>>     resampling_method: bilinear
>>>
>>> We are running MapProxy under Apache2 on Debian Linux behind HTTP proxy.
>>> Packages up to date. I also try to run developlment server with that
>>> config. And output is:
>>>
>>> [2018-11-06 13:21:31,681] mapproxy.source.request - INFO - GET
>>> http://mpp.praha.eu/arcgis/services/DTMP/DTMP/MapServer/WMSServer?styles=&format=image%2Fpng&height=899&bbox=-749443.5125,-1052941.0375,-749412.1875,-1052918.5625&transparent=True&layers=0,1,2,3&service=WMS&srs=EPSG%3A5514&request=GetMap&width=1253&version=1.1.1
>>> 200 10.0 330
>>> [2018-11-06 13:21:31,689] mapproxy.image - DEBUG - converting image from
>>> ImageOptions(encoding_options={}, resampling='bilinear', transparent=True)
>>> -> ImageOptions(bgcolor='#ffffff', colors=256, encoding_options={},
>>> format='image/png', resampling='bilinear', transparent=True)
>>> [2018-11-06 13:21:31,689] mapproxy.image - DEBUG -
>>> file(<mapproxy.image.ReadBufWrapper object at 0x7f67d86e6c10>) -> image
>>> [info] 10.144.35.192 - - [06/Nov/2018 13:21:31] "GET
>>> /wms?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&FORMAT=image/png&TRANSPARENT=true&LAYERS=DTMP&CRS=EPSG%3A5514&STYLES=&WIDTH=1253&HEIGHT=899&BBOX=-749443.5125000001%2C-1052941.0375%2C-749412.1875000001%2C-1052918.5625
>>> HTTP/1.1" 200 -
>>>
>>> But WMS response contains no image, only XML describing error mentioned
>>> above.
>>>
>>> Any advices?
>>>
>>> st 4. 7. 2018 v 15:32 odesílatel Sebastijan Sekulić <
>>> sebastijan.sekulic at gmail.com> napsal:
>>>
>>>> Hi,
>>>> so I am trying to add a WMS source to my MapProxy, but on the demo
>>>> page, I get an error.
>>>> Error while processing image file: cannot identify image file
>>>> <mapproxy.imageReadBufWrapper objerct at 0x7fbed4360f50>.
>>>>
>>>> I have tracked the error to Line 153 in wms.py (It stops at result_bf =
>>>> result.as_buffer(img_opts)), if that helps. I think it should be something
>>>> with pillow having a problem with the image format, but I don't have
>>>> expertise in that.
>>>>
>>>> I don't get any console outputs except request (no errors).
>>>>
>>>> If I make a request with postman or with requests, it renders and
>>>> downloads properly. The image format is png8, and I am using MapProxy 1.11
>>>> on Ubuntu.
>>>>
>>>> If you need .yaml and request, I can provide as a download link or send
>>>> privately, as I don't want to expose source links.
>>>>
>>>> Thanks,
>>>> Seb.
>>>> _______________________________________________
>>>> MapProxy mailing list
>>>> MapProxy at lists.osgeo.org
>>>> https://lists.osgeo.org/mailman/listinfo/mapproxy
>>>
>>> _______________________________________________
>>> MapProxy mailing list
>>> MapProxy at lists.osgeo.org
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>>
>>
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