How to define INFO_FORMAT parameter in WMS request getFeatureInfo?

[MichalGasiorowski]

I want to use default popup info functionality to query WMS layer with getFeatureInfo request.

The request sent after clicking the map contains "INFO_FORMAT=undefined".

Unfortunately the service doesn't accept this value. And this is only parameter which prevents service from response.

The prefered value for this parameter is "text/plain".

I've tried using customLayerParameter (new in 3.18) when defining the service, but it doesn't overwrite default "undefined" value.

So my question is: how to define INFO_FORMAT parameter equal "text/plain" for getFeatureInfo request?

[MichalGasiorowski · Accepted solution]

I missed the WMSLayer property: featureInfoFormat where required type of response can be defined.