Fix extension loading when server sends content-encoding: gzip header

packages/pglite/src/extensionUtils.ts

@@ -35,12 +35,18 @@ export async function loadExtensionBundle(
     const response = await fetch(bundlePath.toString());
     if (!response.ok || !response.body) {
       return null;
+    } else if (response.headers.get('Content-Encoding') === 'gzip') {
+      // Although the bundle is manually compressed, some servers will recognize
+      // that and add a content-encoding header. Fetch will then automatically
+      // decompress the response.
+      return response.blob();
+    } else {
+      const decompressionStream = new DecompressionStream("gzip");
+      const decompressedStream = new Response(
+        response.body.pipeThrough(decompressionStream),
+      );
+      return decompressedStream.blob();
     }
-    const decompressionStream = new DecompressionStream("gzip");
-    const decompressedStream = new Response(
-      response.body.pipeThrough(decompressionStream),
-    );
-    return decompressedStream.blob();
   }
 }