refactor: use environment variables to communicate gcs.Storage config (#186)

* Make server work with google_cloud_storage

* Use pub version

* Update storage.dart

* Env var

* Reverts

* Update storage.dart

* Update storage.dart

* Fix diff a bit

* Update pubspec.yaml

---------

Co-authored-by: Ademola Fadumo <48495111+demolaf@users.noreply.github.com>

Author: brianquinlan

packages/dart_firebase_admin/lib/src/storage/storage.dart

@@ -1,36 +1,14 @@
 import 'dart:convert';
 
 import 'package:google_cloud_storage/google_cloud_storage.dart' as gcs;
-import 'package:http/http.dart' as http;
 import 'package:meta/meta.dart';
 import '../app.dart';
+import '../utils/native_environment.dart';
 
 part 'storage_exception.dart';
 
-/// An [http.BaseClient] that lazily resolves the real client on each request.
-///
-/// This allows [Storage] to be constructed synchronously even though
-/// [FirebaseApp.client] is asynchronous. The underlying client lifecycle is
-/// managed externally (by [FirebaseApp]), so [close] is a no-op here.
-class _DeferredHttpClient extends http.BaseClient {
-  _DeferredHttpClient(this._clientFuture);
-
-  final Future<http.Client> _clientFuture;
-
-  @override
-  Future<http.StreamedResponse> send(http.BaseRequest request) async {
-    return (await _clientFuture).send(request);
-  }
-
-  @override
-  void close() {
-    // The underlying client is managed externally; do not close it here.
-  }
-}
-
 class Storage implements FirebaseService {
   Storage._(this.app) {
-    String? apiEndpoint;
     final isEmulator = Environment.isStorageEmulatorEnabled();
 
     if (isEmulator) {
@@ -42,25 +20,9 @@ class Storage implements FirebaseService {
           'FIREBASE_STORAGE_EMULATOR_HOST should not contain a protocol (http or https).',
         );
       }
-      // The new gcs.Storage adds the http:// scheme automatically when
-      // useAuthWithCustomEndpoint is false, so pass only host:port.
-      apiEndpoint = emulatorHost;
+      setNativeEnvironmentVariable('STORAGE_EMULATOR_HOST', emulatorHost);
     }
-
-    // For emulator, use the provided httpClient (e.g. a mock in tests) or a
-    // plain unauthenticated client. For production, wrap the async auth client
-    // in a _DeferredHttpClient so construction stays synchronous.
-    final http.Client httpClient = isEmulator
-        ? _DeferredHttpClient(
-            Future.value(app.options.httpClient ?? http.Client()),
-          )
-        : _DeferredHttpClient(app.client);
-
-    _delegate = gcs.Storage(
-      client: httpClient,
-      apiEndpoint: apiEndpoint,
-      useAuthWithCustomEndpoint: false,
-    );
+    _delegate = gcs.Storage();
   }
 
   @internal
@@ -73,7 +35,7 @@ class Storage implements FirebaseService {
 
   late final gcs.Storage _delegate;
 
-  gcs.Bucket bucket(String? name) {
+  gcs.Bucket bucket([String? name]) {
     final bucketName = name ?? app.options.storageBucket;
     if (bucketName == null || bucketName.isEmpty) {
       throw FirebaseAppException(
@@ -134,8 +96,6 @@ class Storage implements FirebaseService {
 
   @override
   Future<void> delete() async {
-    // _delegate.close() calls close() on our _DeferredHttpClient, which is a
-    // no-op, so the externally-managed http client is not closed here.
     _delegate.close();
   }
 }

packages/dart_firebase_admin/lib/src/utils/native_environment.dart

@@ -0,0 +1,46 @@
+import 'dart:ffi';
+import 'dart:io';
+
+import 'package:ffi/ffi.dart';
+import 'package:meta/meta.dart';
+
+import '../../dart_firebase_admin.dart';
+
+final int Function(Pointer<Utf8>, Pointer<Utf8>, int) _setenv =
+    DynamicLibrary.process().lookupFunction<
+      Int32 Function(Pointer<Utf8>, Pointer<Utf8>, Int32),
+      int Function(Pointer<Utf8>, Pointer<Utf8>, int)
+    >('setenv');
+
+final int Function(Pointer<Utf16>, Pointer<Utf16>) _setEnvironmentVariableW =
+    DynamicLibrary.open('kernel32.dll').lookupFunction<
+      Int32 Function(Pointer<Utf16>, Pointer<Utf16>),
+      int Function(Pointer<Utf16>, Pointer<Utf16>)
+    >('SetEnvironmentVariableW');
+
+@internal
+void setNativeEnvironmentVariable(String name, String value) {
+  if (Platform.isWindows) {
+    using((arena) {
+      final namePtr = name.toNativeUtf16(allocator: arena);
+      final valuePtr = value.toNativeUtf16(allocator: arena);
+      if (_setEnvironmentVariableW(namePtr, valuePtr) == 0) {
+        throw FirebaseAppException(
+          AppErrorCode.internalError,
+          'Failed to set native environment variable: $name',
+        );
+      }
+    });
+  } else {
+    using((arena) {
+      final namePtr = name.toNativeUtf8(allocator: arena);
+      final valuePtr = value.toNativeUtf8(allocator: arena);
+      if (_setenv(namePtr, valuePtr, 1) == -1) {
+        throw FirebaseAppException(
+          AppErrorCode.internalError,
+          'Failed to set native environment variable: $name',
+        );
+      }
+    });
+  }
+}

packages/dart_firebase_admin/pubspec.yaml

@@ -14,9 +14,12 @@ dependencies:
   collection: ^1.18.0
   dart_jsonwebtoken: ^3.0.0
   equatable: ^2.0.7
+  ffi: ^2.1.2
   google_cloud: ^0.3.0
   google_cloud_firestore: ^0.1.0
-  google_cloud_storage: ^0.5.1
+  # `google_cloud_storage` will not change the surface used by
+  # `dart_firebase_admin`.
+  google_cloud_storage: ">=0.5.1"
   googleapis: ^15.0.0
   googleapis_auth: ^2.2.0
   googleapis_beta: ^9.0.0