[MapServer-dev] Possibly undocumented 8.0 change

Seth G sethg at geographika.co.uk
Mon Aug 29 08:38:02 PDT 2022


Ideally Mapfiles shouldn't be able to crash the server. This change was introduced with the move to C++.
The patch at https://github.com/MapServer/MapServer/pull/6603 should avoid crashes and keep the previous behaviour. 

Ideally though all LAYERS should have a NAME as there are several gotchas if they aren't present. 

Seth

--
web:https://geographika.net
twitter: @geographika

On Mon, Aug 29, 2022, at 3:35 PM, Jeff McKenna wrote:
> Thanks Rich, I'll add it into the MigrationGuide today, great catch.
>
> -jeff
>
>
>
> -- 
> Jeff McKenna
> GatewayGeo: Developers of MS4W, MapServer Consulting and Training
> co-founder of FOSS4G
> http://gatewaygeo.com/
>
>
>
> On 2022-08-29 10:18 a.m., Richard Greenwood wrote:
>> Rahkonen,
>> 
>> Thank you for the explanation of the WMS definitions, but my point is 
>> that this is a breaking change from MapServer map files prior to 8.0. 
>> The change does not return an error message that helps the user identify 
>> the problem, so I thought that it might be helpful to note the change in 
>> the migration guide:
>> https://mapserver.org/MIGRATION_GUIDE.html#migration-8-0 
>> <https://mapserver.org/MIGRATION_GUIDE.html#migration-8-0>
>> 
>> On Mon, Aug 29, 2022 at 5:10 AM Rahkonen Jukka 
>> <jukka.rahkonen at maanmittauslaitos.fi 
>> <mailto:jukka.rahkonen at maanmittauslaitos.fi>> wrote:
>> 
>>     Hi,____
>> 
>>     __ __
>> 
>>     So no need for the “opaque container” that is actually kind of a
>>     hack in Geoserver. In WMS normal layers must have names, this is
>>     from WMS 1.3.0 standard:____
>> 
>> 
>>     7.2.4.6.3 Name____
>> 
>>     If, and only if, a layer has a <Name>, then it is a map layer that
>>     can be requested by using that Name in the____
>> 
>>     LAYERS parameter of a GetMap request. A Layer that contains a <Name>
>>     element is referred to as a “named____
>> 
>>     layer” in this International Standard. If the layer has a Title but
>>     no Name, then that layer is only a category title for____
>> 
>>     all the layers nested within. A server that advertises a Layer
>>     containing a Name element shall be able to accept____
>> 
>>     that Name as the value of LAYERS argument in a GetMap request and
>>     return the corresponding map. A client____
>> 
>>     shall not attempt to request a layer that has a Title but no Name.____
>> 
>>     __ __
>> 
>>     There is something documented about the layer names in
>>     https://mapserver.gis.umn.edu/ogc/wms_server.html
>>     <https://mapserver.gis.umn.edu/ogc/wms_server.html> but not really
>>     that the rules apply also if layer belongs to a group:____
>> 
>>     __ __
>> 
>>     “Layer Name and wms_title metadata:____
>> 
>>     __ __
>> 
>>     Every individual layer needs its own unique name and title. Layer
>>     names are also used in GetMap and GetFeatureInfo requests to refer
>>     to layers that should be included in the map output and in the
>>     query. Layer names must start with a letter when setting up a WMS
>>     server (layer names should not start with a digit or have spaces in
>>     them).”____
>> 
>>     __ __
>> 
>>     -Jukka Rahkonen-____
>> 
>>     __ __
>> 
>>     __ __
>> 
>>     *Lähettäjä:* Richard Greenwood <richard.greenwood at gmail.com
>>     <mailto:richard.greenwood at gmail.com>>
>>     *Lähetetty:* maanantai 29. elokuuta 2022 13.40
>>     *Vastaanottaja:* Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi
>>     <mailto:jukka.rahkonen at maanmittauslaitos.fi>>
>>     *Kopio:* Seth G <sethg at geographika.co.uk
>>     <mailto:sethg at geographika.co.uk>>; MapServer Devs
>>     <mapserver-dev at lists.osgeo.org <mailto:mapserver-dev at lists.osgeo.org>>
>>     *Aihe:* Re: [MapServer-dev] Possibly undocumented 8.0 change____
>> 
>>     __ __
>> 
>>     No, just laziness. It's not a big deal, but maybe should be
>>     documented. ____
>> 
>>     __ __
>> 
>>     On Mon, Aug 29, 2022, 11:58 AM Rahkonen Jukka
>>     <jukka.rahkonen at maanmittauslaitos.fi
>>     <mailto:jukka.rahkonen at maanmittauslaitos.fi>> wrote:____
>> 
>>         Hi Richard,____
>> 
>>         ____
>> 
>>         Is your aim with using GROUP without NAME to hide the layer from
>>         GetCapabilities so that users cannot see or request that layer
>>         separately but only as a member of a group? Like “opaque
>>         container” in Geoserver
>>         https://docs.geoserver.org/latest/en/user/data/webadmin/layergroups.html <https://eur06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdocs.geoserver.org%2Flatest%2Fen%2Fuser%2Fdata%2Fwebadmin%2Flayergroups.html&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=fqqIU8Ul9FjwpjHXKlWjAMqT9OGaL7oLQFLdoKnjxto%3D&reserved=0>____
>> 
>>         ____
>> 
>>         -Jukka Rahkonen-____
>> 
>>         ____
>> 
>>         ____
>> 
>>         ____
>> 
>>         *Lähettäjä:* Seth G <sethg at geographika.co.uk
>>         <mailto:sethg at geographika.co.uk>>
>>         *Lähetetty:* maanantai 29. elokuuta 2022 10.45
>>         *Vastaanottaja:* Richard Greenwood <richard.greenwood at gmail.com
>>         <mailto:richard.greenwood at gmail.com>>; Rahkonen Jukka
>>         <jukka.rahkonen at maanmittauslaitos.fi
>>         <mailto:jukka.rahkonen at maanmittauslaitos.fi>>
>>         *Kopio:* MapServer Devs <mapserver-dev at lists.osgeo.org
>>         <mailto:mapserver-dev at lists.osgeo.org>>
>>         *Aihe:* Re: [MapServer-dev] Possibly undocumented 8.0 change____
>> 
>>         ____
>> 
>>         Hi Richard,____
>> 
>>         ____
>> 
>>         Could you create an issue for this on GitHub?____
>> 
>>         It looks like it could relate to the move to C++.____
>> 
>>         Thanks,____
>> 
>>         ____
>> 
>>         Seth____
>> 
>>         ____
>> 
>>         --____
>> 
>>         web:https://geographika.net
>>         <https://eur06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgeographika.net%2F&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=DS8KRO6ZFREovCqteYci3oD%2B9sDxjv2TTCHbANGJJaI%3D&reserved=0>____
>> 
>>         twitter: @geographika____
>> 
>>         ____
>> 
>>         ____
>> 
>>         On Mon, Aug 29, 2022, at 9:34 AM, Richard Greenwood wrote:____
>> 
>>             An empty string for the NAME works without error. I set
>>             the MS_DEBUGLEVEL to 5 and nothing is written to the error
>>             file when this error occurs.____
>> 
>>             ____
>> 
>>             On Mon, Aug 29, 2022 at 12:44 AM Rahkonen Jukka
>>             <jukka.rahkonen at maanmittauslaitos.fi
>>             <mailto:jukka.rahkonen at maanmittauslaitos.fi>> wrote:____
>> 
>>                 Hi,____
>> 
>>                 ____
>> 
>>                 What happens if you use an empty NAME?____
>> 
>>                 ____
>> 
>>                 -Jukka Rahkonen-____
>> 
>>                 ____
>> 
>>                 *Lähettäjä:* MapServer-dev
>>                 <mapserver-dev-bounces at lists.osgeo.org
>>                 <mailto:mapserver-dev-bounces at lists.osgeo.org>>
>>                 *Puolesta *Richard Greenwood____
>> 
>>                 *Lähetetty:* maanantai 29. elokuuta 2022 9.06____
>> 
>>                 *Vastaanottaja:* Seth G <sethg at geographika.co.uk
>>                 <mailto:sethg at geographika.co.uk>>____
>> 
>>                 *Kopio:* MapServer Devs <mapserver-dev at lists.osgeo.org
>>                 <mailto:mapserver-dev at lists.osgeo.org>>____
>> 
>>                 *Aihe:* Re: [MapServer-dev] Possibly undocumented 8.0
>>                 change____
>> 
>>                 ____
>> 
>>                 Yes, it's with a WMS request. Apache throws a 500 error
>>                 "End of script output before headers". I define a LAYER
>>                 with a GROUP but no NAME. I don't believe METADATA plays
>>                 into it because I commented out the METADATA block and
>>                 it fails in the same way.____
>> 
>>                 ____
>> 
>>                 On Sun, Aug 28, 2022 at 3:07 PM Seth G
>>                 <sethg at geographika.co.uk
>>                 <mailto:sethg at geographika.co.uk>> wrote:____
>> 
>>                     Hi Richard,____
>> 
>>                     ____
>> 
>>                     Do you have more details - is this when using WMS?
>>                     Is there an error that appears?____
>> 
>>                     For WMS there is a known conflict between GROUP and
>>                     wms_layer_group in a METADATA block, but this sounds
>>                     like something different.____
>> 
>>                     ____
>> 
>>                     Seth____
>> 
>>                     ____
>> 
>>                     --____
>> 
>>                     web:https://geographika.net
>>                     <https://eur06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgeographika.net%2F&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=DS8KRO6ZFREovCqteYci3oD%2B9sDxjv2TTCHbANGJJaI%3D&reserved=0>____
>> 
>>                     twitter: @geographika____
>> 
>>                     ____
>> 
>>                     ____
>> 
>>                     On Sun, Aug 28, 2022, at 3:53 PM, Richard Greenwood
>>                     wrote:____
>> 
>>                         I didn't see mention of this in the docs,
>>                         apologies if I missed it. It appears that as of
>>                         8.0 a layer must have a NAME. In the past it has
>>                         been possible for a layer not to have a NAME if
>>                         it had a  GROUP.____
>> 
>>                         ____
>> 
>>                         -- ____
>> 
>>                         Richard W. Greenwood____
>> 
>>                         www.greenwoodmap.com
>>                         <https://eur06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.greenwoodmap.com%2F&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=42axJiUotL4lrds1YbVXt8cc7Ed0IC%2B2IlySiRF5R3Q%3D&reserved=0>____
>> 
>>                         ___________________________________________________
>> 
>>                         MapServer-dev mailing list____
>> 
>>                         MapServer-dev at lists.osgeo.org
>>                         <mailto:MapServer-dev at lists.osgeo.org>____
>> 
>>                         https://lists.osgeo.org/mailman/listinfo/mapserver-dev <https://eur06.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.osgeo.org%2Fmailman%2Flistinfo%2Fmapserver-dev&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=RGeZuORawrRt55QWp1f9B1n3o6rjqogikR2zw4lHyF0%3D&reserved=0>____
>> 
>>                         ____
>> 
>>                     ____
>> 
>>                 ____
>> 
>>                 ____
>> 
>>                 -- ____
>> 
>>                 Richard W. Greenwood____
>> 
>>                 www.greenwoodmap.com
>>                 <https://eur06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.greenwoodmap.com%2F&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=42axJiUotL4lrds1YbVXt8cc7Ed0IC%2B2IlySiRF5R3Q%3D&reserved=0>____
>> 
>>             ____
>> 
>>             ____
>> 
>>             -- ____
>> 
>>             Richard W. Greenwood____
>> 
>>             www.greenwoodmap.com
>>             <https://eur06.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.greenwoodmap.com%2F&data=05%7C01%7Cjukka.rahkonen%40maanmittauslaitos.fi%7C4e29f6da035b41ae58da08da89aace2d%7Cc4f8a63255804a1c92371d5a571b71fa%7C0%7C0%7C637973663938909073%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=42axJiUotL4lrds1YbVXt8cc7Ed0IC%2B2IlySiRF5R3Q%3D&reserved=0>____
>> 
>>         ____
>> 
>> 
>> 
>> -- 
>> Richard W. Greenwood
>> www.greenwoodmap.com <http://www.greenwoodmap.com>
>> 
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>> MapServer-dev at lists.osgeo.org
>> https://lists.osgeo.org/mailman/listinfo/mapserver-dev
>
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