support custom URL parameters in a GetLegendGraphic request for a layer without a style configured

CHANGES.md

@@ -2,6 +2,7 @@
 
 #### next release (8.7.8)
 
+- support URL parameters in a GetLegendGraphic request for a layer without a style configured
 - [The next improvement]
 
 #### 8.7.7 - 2024-10-01

lib/Models/Catalog/Ows/WebMapServiceCapabilitiesStratum.ts

@@ -203,7 +203,7 @@ export default class WebMapServiceCapabilitiesStratum extends LoadableStratum(
         legendUri = URI(
           proxyCatalogItemUrl(
             this.catalogItem,
-            this.catalogItem.url.split("?")[0]
+            this.catalogItem.getLegendBaseUrl()
           )
         );
         legendUri

lib/Models/Catalog/Ows/WebMapServiceCatalogItem.ts

@@ -364,6 +364,20 @@ class WebMapServiceCatalogItem
     this.setTrait(CommonStrata.user, "isShowingDiff", false);
   }
 
+  getLegendBaseUrl(): string {
+    // Remove problematic query parameters from URL
+    const baseUrl = QUERY_PARAMETERS_TO_REMOVE.reduce(
+      (url, parameter) =>
+        url
+          .removeQuery(parameter)
+          .removeQuery(parameter.toUpperCase())
+          .removeQuery(parameter.toLowerCase()),
+      new URI(this.url)
+    );
+
+    return baseUrl.toString();
+  }
+
   getLegendUrlForStyle(
     styleId: string,
     firstDate?: JulianDate,

test/Models/Catalog/Ows/WebMapServiceCatalogItemSpec.ts

@@ -972,6 +972,40 @@ describe("WebMapServiceCatalogItem", function () {
       .catch(done.fail);
   });
 
+  it("supports parameters in a GetLegendGraphic request for a layer without a style configured", function (done) {
+    const terria = new Terria();
+    const wmsItem = new WebMapServiceCatalogItem("some-layer", terria);
+    runInAction(() => {
+      wmsItem.setTrait(
+        CommonStrata.definition,
+        "url",
+        "http://example.com/mapserv?map=%2Fmap%2Fexample.map"
+      );
+      wmsItem.setTrait(
+        CommonStrata.definition,
+        "getCapabilitiesUrl",
+        "test/WMS/styles_and_dimensions.xml"
+      );
+      wmsItem.setTrait(CommonStrata.definition, "layers", "A");
+      wmsItem.setTrait(
+        CommonStrata.definition,
+        "supportsGetLegendGraphic",
+        true
+      );
+    });
+
+    wmsItem
+      .loadMetadata()
+      .then(function () {
+        expect(wmsItem.legends.length).toBe(1);
+        expect(wmsItem.legends[0].url).toBe(
+          "http://example.com/mapserv?map=%2Fmap%2Fexample.map&service=WMS&version=1.3.0&request=GetLegendGraphic&format=image%2Fpng&sld_version=1.1.0&layer=A"
+        );
+      })
+      .then(done)
+      .catch(done.fail);
+  });
+
   it("fetches legend with colourScaleRange", function (done) {
     const terria = new Terria();
     const wmsItem = new WebMapServiceCatalogItem("some-layer", terria);