fix: hide unavailable GeoServer layers

src/features/workbench/map/geoserver-layer-availability.ts

@@ -0,0 +1,111 @@
+import { GEOSERVER_WORKSPACE, MAP_URL } from "./geoserver-config";
+import {
+  GEOSERVER_WATER_NETWORK_SOURCE_IDS,
+  SOURCE_LAYERS,
+  SUPPLY_LAYER_CATALOG,
+  type GeoServerWaterNetworkSourceId
+} from "./sources";
+
+type GeoServerSupplyLayerCatalogItem = Extract<
+  (typeof SUPPLY_LAYER_CATALOG)[number],
+  { sourceLayer: string }
+>;
+
+export type DataDependentGeoServerSourceId = Extract<
+  GeoServerSupplyLayerCatalogItem,
+  { availability: "probe" }
+>["id"];
+
+export const DATA_DEPENDENT_GEOSERVER_SOURCE_IDS: DataDependentGeoServerSourceId[] = SUPPLY_LAYER_CATALOG.filter(
+  (layer): layer is Extract<GeoServerSupplyLayerCatalogItem, { availability: "probe" }> =>
+    layer.sourceLayer !== undefined && layer.availability === "probe"
+).map((layer) => layer.id);
+
+export type GeoServerLayerAvailability = {
+  availableSourceIds: GeoServerWaterNetworkSourceId[];
+  emptySourceIds: DataDependentGeoServerSourceId[];
+  failedSourceIds: DataDependentGeoServerSourceId[];
+};
+
+export const REQUIRED_GEOSERVER_SOURCE_IDS: GeoServerWaterNetworkSourceId[] = SUPPLY_LAYER_CATALOG.filter(
+  (layer): layer is Extract<GeoServerSupplyLayerCatalogItem, { availability: "required" }> =>
+    layer.sourceLayer !== undefined && layer.availability === "required"
+).map((layer) => layer.id);
+
+export function createGeoServerLayerHitsUrl(sourceId: DataDependentGeoServerSourceId) {
+  const params = new URLSearchParams({
+    service: "WFS",
+    version: "2.0.0",
+    request: "GetFeature",
+    typeNames: `${GEOSERVER_WORKSPACE}:${SOURCE_LAYERS[sourceId]}`,
+    resultType: "hits"
+  });
+
+  return new URL(`${MAP_URL}/${GEOSERVER_WORKSPACE}/ows?${params.toString()}`);
+}
+
+export async function fetchGeoServerLayerFeatureCount(
+  sourceId: DataDependentGeoServerSourceId,
+  signal?: AbortSignal
+) {
+  const response = await fetch(createGeoServerLayerHitsUrl(sourceId), {
+    headers: { Accept: "application/xml, text/xml" },
+    signal
+  });
+  const payload = await response.text();
+  if (!response.ok) {
+    if (/Feature type\s+\S+\s+unknown/i.test(payload)) return 0;
+    throw new Error(`GeoServer ${sourceId} 图层探测失败：HTTP ${response.status}`);
+  }
+
+  const match = payload.match(/\bnumberMatched\s*=\s*["'](\d+|unknown)["']/i);
+  if (!match) {
+    throw new Error(`GeoServer ${sourceId} 图层探测响应缺少 numberMatched`);
+  }
+
+  if (match[1].toLowerCase() === "unknown") return 1;
+
+  const count = Number(match[1]);
+  if (!Number.isSafeInteger(count) || count < 0) {
+    throw new Error(`GeoServer ${sourceId} 图层探测返回无效数量`);
+  }
+  return count;
+}
+
+export async function resolveGeoServerLayerAvailability(
+  signal?: AbortSignal
+): Promise<GeoServerLayerAvailability> {
+  const results = await Promise.allSettled(
+    DATA_DEPENDENT_GEOSERVER_SOURCE_IDS.map(async (sourceId) => ({
+      sourceId,
+      count: await fetchGeoServerLayerFeatureCount(sourceId, signal)
+    }))
+  );
+  const availableOptionalSourceIds: DataDependentGeoServerSourceId[] = [];
+  const emptySourceIds: DataDependentGeoServerSourceId[] = [];
+  const failedSourceIds: DataDependentGeoServerSourceId[] = [];
+
+  results.forEach((result, index) => {
+    const sourceId = DATA_DEPENDENT_GEOSERVER_SOURCE_IDS[index];
+    if (result.status === "rejected") {
+      failedSourceIds.push(sourceId);
+    } else if (result.value.count > 0) {
+      availableOptionalSourceIds.push(sourceId);
+    } else {
+      emptySourceIds.push(sourceId);
+    }
+  });
+
+  const availableSourceIdSet = new Set<GeoServerWaterNetworkSourceId>([
+    ...REQUIRED_GEOSERVER_SOURCE_IDS,
+    ...availableOptionalSourceIds
+  ]);
+
+  return {
+    availableSourceIds: GEOSERVER_WATER_NETWORK_SOURCE_IDS.filter((sourceId) =>
+      availableSourceIdSet.has(sourceId)
+    ),
+    emptySourceIds,
+    failedSourceIds
+  };
+}