detailed error handling for cloudflare worker

serverless/cloudflare/worker.ts

@@ -10,6 +10,12 @@ interface CacheEntry {
   buffer: DataView;
 }
 
+class KeyNotFoundError extends Error {
+  constructor(message: string) {
+    super(message);
+  }
+}
+
 export class LRUCache {
   entries: Map<string, CacheEntry>;
   counter: number;
@@ -35,6 +41,9 @@ export class LRUCache {
     let resp = await bucket.get(key, {
       range: { offset: offset, length: length },
     });
+    if (!resp) {
+      throw new KeyNotFoundError("Key not found");
+    }
     let a = await (resp as R2ObjectBody).arrayBuffer();
     let d = new DataView(a);
 
@@ -110,12 +119,20 @@ export default {
       let source = new TempSource();
 
       let p = new PMTiles(source);
+      try {
         let metadata = await p.metadata();
+
+        if (z < metadata.minzoom || z > metadata.maxzoom) {
+          return new Response("Tile not found", { status: 404 });
+        }
         let entry = await p.getZxy(z, x, y);
         if (entry) {
-        let tile = await env.BUCKET.get(pmtiles_path(env.PMTILES_PATH, name), {
+          let tile = await env.BUCKET.get(
+            pmtiles_path(env.PMTILES_PATH, name),
+            {
               range: { offset: entry.offset, length: entry.length },
-        });
+            }
+          );
 
           let headers = new Headers();
           headers.set("Access-Control-Allow-Origin", "*");
@@ -130,8 +147,17 @@ export default {
             headers: headers,
             encodeBody: "manual",
           } as any);
+        } else {
+          return new Response(undefined, { status: 204 });
+        }
+      } catch (e) {
+        if (e instanceof KeyNotFoundError) {
+          return new Response("Archive not found", { status: 404 });
+        } else {
+          throw e;
         }
       }
-    return new Response("Not Found");
+    }
+    return new Response("Invalid tile URL", { status: 400 });
   },
 };