[mapserver-users] cgi-error: End of script output before headers mapserv

[Rahkonen Jukka (MML)]

Hi,

I would suspect data, especially because it seems to be OSM data. Perhaps some invalid polygon again.

You use &layers=default and I suppose that it means all the layers from your mapfile together. In that case I would try to catch the failing layer by adding layers one by one and in groups (first &layers=layer1, then &layers=layer2, then &layers=layer1,layer2).

Hopefully that way you can find the failing layer, and then because you know the BBOX you may find the nasty geometry from the database. Without your data and mapfile it is rather useless to make very much guesswork, but a small change in bbox may select/not select a bad geometry, of change of bbox may change scale so much that source data come from a different table if you have a scale dependent layer group in the mapfile etc.

If the issue is due to bad geometry and you use PostGIS you may find it with ST_IsValid and ST_IsValidReason, and correct with ST_MakeValid.

-Jukka Rahkonen-

Lähettäjä: mapserver-users <mapserver-users-bounces at lists.osgeo.org> Puolesta Johannes Paul
Lähetetty: keskiviikko 22. tammikuuta 2020 13.02
Vastaanottaja: mapserver-users at lists.osgeo.org
Aihe: [mapserver-users] cgi-error: End of script output before headers mapserv

Hello,
my mapserver is having a very strange behaviour, which I can't explain, nor debug.
I'm using mapserver 7.0.0 along with apache http server 2.4.6.

Most of the time, the server is working just fine, i.e. when I request a typical URL, I get my image back:

http://10.0.0.22/cgi-bin/mapserv?map=/var/www/html/osm-transp-en-default.map&VERSION=1.1.0&REQUEST=getmap&SERVICE=wms&STYLES=&BBOX=-9.143,38.746,-9.140,38.748&HEIGHT=256&WIDTH=256&LAYERS=default&FORMAT=image/png&SRS=EPSG:4326&TRANSPARENT=true

but then, when I slightly change bbox values, I get an internal server error (500):

http://10.0.0.22/cgi-bin/mapserv?map=/var/www/html/osm-transp-en-default.map&VERSION=1.1.0&REQUEST=getmap&SERVICE=wms&STYLES=&BBOX=-9.1433,38.7460,-9.1406,38.7487&HEIGHT=256&WIDTH=256&LAYERS=default&FORMAT=image/png&SRS=EPSG:4326&TRANSPARENT=true

I don't get any mapserver error log, but I do get an apache error log saying:
[cgi:error] End of script output before headers: mapserv

This is really an strange behaviour which I can't explain.
Did anyone already experienced a similar situation ?
Thanks
Jo
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