Support StorageReference#writeToFile

packages/firebase_storage/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.2
+
+* Added support for StorageReference `writeToFile`.
+
 ## 0.3.1
 
 * Added support for StorageReference functions: `getParent`, `getRoot`, `getStorage`, `getName`, `getPath`, `getBucket`.

packages/firebase_storage/android/src/main/java/io/flutter/plugins/firebase/storage/FirebaseStoragePlugin.java

@@ -10,6 +10,7 @@
 import com.google.android.gms.tasks.OnSuccessListener;
 import com.google.android.gms.tasks.Task;
 import com.google.firebase.FirebaseApp;
+import com.google.firebase.storage.FileDownloadTask;
 import com.google.firebase.storage.FirebaseStorage;
 import com.google.firebase.storage.StorageMetadata;
 import com.google.firebase.storage.StorageReference;
@@ -71,6 +72,9 @@ public void onMethodCall(MethodCall call, final Result result) {
       case "StorageReference#updateMetadata":
         updateMetadata(call, result);
         break;
+      case "StorageReference#writeToFile":
+        writeToFile(call, result);
+        break;
       default:
         result.notImplemented();
         break;
@@ -271,4 +275,26 @@ public void onFailure(@NonNull Exception e) {
           }
         });
   }
+
+  private void writeToFile(MethodCall call, final Result result) {
+    String path = call.argument("path");
+    String filePath = call.argument("filePath");
+    File file = new File(filePath);
+    StorageReference ref = firebaseStorage.getReference().child(path);
+    FileDownloadTask downloadTask = ref.getFile(file);
+    downloadTask.addOnSuccessListener(
+        new OnSuccessListener<FileDownloadTask.TaskSnapshot>() {
+          @Override
+          public void onSuccess(FileDownloadTask.TaskSnapshot taskSnapshot) {
+            result.success(taskSnapshot.getTotalByteCount());
+          }
+        });
+    downloadTask.addOnFailureListener(
+        new OnFailureListener() {
+          @Override
+          public void onFailure(@NonNull Exception e) {
+            result.error("download_error", e.getMessage(), null);
+          }
+        });
+  }
 }

packages/firebase_storage/example/lib/main.dart

@@ -36,6 +36,7 @@ class _MyHomePageState extends State<MyHomePage> {
   String _name;
   String _bucket;
   String _path;
+  String _tempFileContents;
 
   Future<Null> _uploadFile() async {
     final Directory systemTempDir = Directory.systemTemp;
@@ -44,7 +45,7 @@ class _MyHomePageState extends State<MyHomePage> {
     assert(await file.readAsString() == kTestString);
     final String rand = "${new Random().nextInt(10000)}";
     final StorageReference ref =
-        FirebaseStorage.instance.ref().child('text').child("foo$rand.txt");
+        FirebaseStorage.instance.ref().child('text').child('foo$rand.txt');
     final StorageUploadTask uploadTask =
         ref.putFile(file, const StorageMetadata(contentLanguage: "en"));
 
@@ -54,11 +55,24 @@ class _MyHomePageState extends State<MyHomePage> {
     final String bucket = await ref.getBucket();
     final String path = await ref.getPath();
 
+    final File tempFile = new File('${systemTempDir.path}/tmp.txt');
+    if (tempFile.existsSync()) {
+      await tempFile.delete();
+    }
+    await tempFile.create();
+    assert(await tempFile.readAsString() == "");
+    final StorageFileDownloadTask task = ref.writeToFile(tempFile);
+    final int bytes = (await task.future).totalByteCount;
+    final String tempFileContents = await tempFile.readAsString();
+    assert(tempFileContents == kTestString);
+    assert(bytes == kTestString.length);
+
     setState(() {
       _fileContents = downloadData.body;
       _name = name;
       _path = path;
       _bucket = bucket;
+      _tempFileContents = tempFileContents;
     });
   }
 
@@ -73,10 +87,12 @@ class _MyHomePageState extends State<MyHomePage> {
           mainAxisSize: MainAxisSize.min,
           children: <Widget>[
             _fileContents == null
-                ? const Text('Press the button to upload a file')
+                ? const Text('Press the button to upload a file \n '
+                    'and download its contents to tmp.txt')
                 : new Text(
                     'Success!\n Uploaded $_name \n to bucket: $_bucket\n '
-                        'at path: $_path \n\nFile contents: "$_fileContents"',
+                        'at path: $_path \n\nFile contents: "$_fileContents" \n'
+                        'Wrote "$_tempFileContents" to tmp.txt',
                     style: const TextStyle(
                         color: const Color.fromARGB(255, 0, 155, 0)),
                   )

packages/firebase_storage/ios/Classes/FirebaseStoragePlugin.m

@@ -60,6 +60,8 @@ - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result
     [self getMetadata:call result:result];
   } else if ([@"StorageReference#updateMetadata" isEqualToString:call.method]) {
     [self updateMetadata:call result:result];
+  } else if ([@"StorageReference#writeToFile" isEqualToString:call.method]) {
+    [self writeToFile:call result:result];
   } else {
     result(FlutterMethodNotImplemented);
   }
@@ -156,6 +158,24 @@ - (void)getData:(FlutterMethodCall *)call result:(FlutterResult)result {
             }];
 }
 
+- (void)writeToFile:(FlutterMethodCall *)call result:(FlutterResult)result {
+  NSString *path = call.arguments[@"path"];
+  NSString *filePath = call.arguments[@"filePath"];
+  NSURL *localURL = [NSURL fileURLWithPath:filePath];
+  FIRStorageReference *ref = [[FIRStorage storage].reference child:path];
+  FIRStorageDownloadTask *task = [ref writeToFile:localURL];
+  [task observeStatus:FIRStorageTaskStatusSuccess
+              handler:^(FIRStorageTaskSnapshot *snapshot) {
+                result(@(snapshot.progress.totalUnitCount));
+              }];
+  [task observeStatus:FIRStorageTaskStatusFailure
+              handler:^(FIRStorageTaskSnapshot *snapshot) {
+                if (snapshot.error != nil) {
+                  result(snapshot.error.flutterError);
+                }
+              }];
+}
+
 - (void)getMetadata:(FlutterMethodCall *)call result:(FlutterResult)result {
   NSString *path = call.arguments[@"path"];
   FIRStorageReference *ref = [[FIRStorage storage].reference child:path];

packages/firebase_storage/lib/firebase_storage.dart

@@ -125,6 +125,15 @@ class StorageReference {
     );
   }
 
+  /// Asynchronously downloads the object at this [StorageReference] to a
+  /// specified system file.
+  StorageFileDownloadTask writeToFile(File file) {
+    final StorageFileDownloadTask task =
+        new StorageFileDownloadTask._(_pathComponents.join("/"), file);
+    task._start();
+    return task;
+  }
+
   /// Asynchronously retrieves a long lived download URL with a revokable token.
   /// This can be used to share the file with others, but can be revoked by a
   /// developer in the Firebase Console if desired.
@@ -245,6 +254,29 @@ class StorageMetadata {
   final String contentType;
 }
 
+class StorageFileDownloadTask {
+  final String _path;
+  final File _file;
+
+  StorageFileDownloadTask._(this._path, this._file);
+
+  Future<void> _start() async {
+    final int totalByteCount = await FirebaseStorage.channel.invokeMethod(
+      "StorageReference#writeToFile",
+      <String, dynamic>{
+        'filePath': _file.absolute.path,
+        'path': _path,
+      },
+    );
+    _completer
+        .complete(new FileDownloadTaskSnapshot(totalByteCount: totalByteCount));
+  }
+
+  Completer<FileDownloadTaskSnapshot> _completer =
+      new Completer<FileDownloadTaskSnapshot>();
+  Future<FileDownloadTaskSnapshot> get future => _completer.future;
+}
+
 abstract class StorageUploadTask {
   final String _path;
   final StorageMetadata _metadata;
@@ -313,3 +345,8 @@ class UploadTaskSnapshot {
   UploadTaskSnapshot({this.downloadUrl});
   final Uri downloadUrl;
 }
+
+class FileDownloadTaskSnapshot {
+  FileDownloadTaskSnapshot({this.totalByteCount});
+  final int totalByteCount;
+}

packages/firebase_storage/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Firebase Cloud Storage, a powerful, simple, and
   cost-effective object storage service for Android and iOS.
 author: Flutter Team <[email protected]>
 homepage: https://github.com/flutter/plugins/tree/master/packages/firebase_storage
-version: 0.3.1
+version: 0.3.2
 
 flutter:
   plugin: