QGIS Server WMS GetFeatureInfo does not evaluate represent_value expression in maptip

[mdouchin]

Describe the bug

When getting HTML GetFeatureInfo response from QGIS Server, for a vector layer with a maptip configured, the represent_value method which replaces the field value with its represented value (for example for Value Relation edit widget) is not evaluated in the server context.

How to Reproduce

1. Add any vector layer with a QGIS project
2. Configure an edit widget with Value Map (or value relation, etc.) for example for a category field
3. Add content in the Maptip tab of the Vector layer properties, with the expression represent_value("category")
4. In QGIS desktop, the maptip shows the correct value
5. Publish the QGIS project with QGIS Server, and use the GetFeatureInfo request with HTML format -> the content is wrong and contains plain text containing the word represent_value

QGIS and OS versions

Test with QGIS Server 3.4.9

[nboisteault]

Does not work with QGIS Server 3.16.3 neither.

[elpaso]

Any chance to have a test project and data?

[mdouchin]

Old issue ;) I need to re-test it and provide QGIS project with test data

[github-actions]

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[mdouchin]

@nboisteault or @Gustry do you have any test project ?

[nboisteault]

I'm currently creating a project.

[nboisteault]

represent_value.zip

You'll find in this zip a QGIS project with two layers in a geopackage. Use the maptip tool on the only point of point_layer, you'll have first displayed.

Then you can execute this query (change path accordingly) :
QUERY_STRING="MAP=/srv/projects/tests/represent_value.qgs&SERVICE=WMS&REQUEST=GetFeatureInfo&QUERY_LAYERS=point_layer&I=645&J=345&CRS=EPSG:2154&BBOX=749647.283424,6268207.177805,798145.50542,6292178.475747&HEIGHT=906&WIDTH=1833&WITH_MAPTIP=true" /usr/lib/cgi-bin/qgis_mapserv.fcgi
You'll have this result :

GetFeatureInfo results

Layer 'point_layer'
Feature 1
fid = '1'
value = 'first'
maptip = '[%  represent_value(  "value" ) %]'

As you see, expression is not interpreted. I had the same bug with relation_aggregate() too.

Thanks @elpaso for your help.

[virtusmankind]

I'm facing same issue with the relation_aggregate function.
QGis server 3.20 does not show popups (with Lizmap web client) nor does it represent the style of the features, created with the relation_aggregate function (rules based style) while it works perfectly with QGis desktop 3.20

[mdouchin]

Muchas gracias !