Filter application requires grouped layers

[ddrinka]

It seems like WMS filters can only apply to layers belonging to a group:

qwc2/utils/LayerUtils.js

Line 201 in 68e0733

if (filter.filterParams) {

QGIS Server does not have that restriction. I'm able to apply a FILTER parameter to a request for a single layer.

[manisandro]

The filter plugin will currently only apply to theme layers, and any theme WMS from QGIS will come with sublayers (the toplevel layer begin the project itself, and the sublayers mirroring the QGIS layertree). How did you hit this restriction?

[ddrinka]

I'm providing a WMS URL via a query parameter (l=wms:https://...#LayerName) that I want to filter using a custom filter, also via query parameters. I've tried grouping the layers and providing the group to the query, but then the filter isn't able to "see" the sublayers--I didn't quite manage to dig into what was actually happening there, but it didn't just work.

I'm absolutely open to understanding better ways to use the url-based layer functionality. I'm very much in trial-and-error mode. For instance, it looks like there might be a way to actually load a new theme configuration from a URL to a JSON file rather than a WMS layer directly? But I haven't figured that out yet, and can't find it in any documentation.

[manisandro]

Maybe it actually works. Can you try with this change

diff --git a/utils/LayerUtils.js b/utils/LayerUtils.js
index 8572603d..ff65a8a6 100644
--- a/utils/LayerUtils.js
+++ b/utils/LayerUtils.js
@@ -198,17 +198,17 @@ const LayerUtils = {
                 STYLES: styles.join(","),
                 ...layer.dimensionValues
             };
-            if (filter.filterParams) {
-                newParams.FILTER = Object.entries(filter.filterParams).reduce((res, [layername, filters]) => {
-                    if (!layerNames.includes(layername)) {
-                        return res;
-                    }
-                    return [...res, layername + ":" + filters.map(expr => Array.isArray(expr) ? LayerUtils.formatFilterExpr(expr) : "AND").join(" ")];
-                }, []).join(";");
-            }
-            if (filter.filterGeom) {
-                newParams.FILTER_GEOM = VectorLayerUtils.geoJSONGeomToWkt(filter.filterGeom);
-            }
+        }
+        if (filter.filterParams) {
+            newParams.FILTER = Object.entries(filter.filterParams).reduce((res, [layername, filters]) => {
+                if (!newParams.LAYERS.split(",").includes(layername)) {
+                    return res;
+                }
+                return [...res, layername + ":" + filters.map(expr => Array.isArray(expr) ? LayerUtils.formatFilterExpr(expr) : "AND").join(" ")];
+            }, []).join(";");
+        }
+        if (filter.filterGeom) {
+            newParams.FILTER_GEOM = VectorLayerUtils.geoJSONGeomToWkt(filter.filterGeom);
         }
 
         return {

[ddrinka]

That's the change I had in mind. I'm targeting an existing install so I can't just patch that in, but I can try to set up a local copy to test with. It'll probably be a couple days.