Adding upload progress

.gitignore

@@ -74,3 +74,6 @@ build/
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
 !/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+
+# .fvm
+.fvm

example/lib/src/image_picker_example.dart

@@ -17,6 +17,7 @@ class _ImagePickerExampleState extends State<ImagePickerExample> {
   final picker = ImagePicker();
   PickedFile _pickedFile;
   bool _uploading = false;
+  double _uploadingPercentage = 0.0;
 
   Future getImage() async {
     final image = await picker.getImage(source: ImageSource.gallery);
@@ -54,7 +55,9 @@ class _ImagePickerExampleState extends State<ImagePickerExample> {
         _buildImage(),
         TextButton(
           onPressed: _uploading ? null : _upload,
-          child: _uploading ? Text('Uploading...') : Text('Upload'),
+          child: _uploading
+              ? Text('${_uploadingPercentage.toStringAsFixed(2)}%')
+              : Text('Upload'),
         ),
       ],
     );
@@ -75,6 +78,11 @@ class _ImagePickerExampleState extends State<ImagePickerExample> {
             'caption': 'An example image',
           },
         ),
+        onSendProgress: (count, total) {
+          setState(() {
+            _uploadingPercentage = (count / total) * 100;
+          });
+        },
       );
       print(res);
     } on CloudinaryException catch (e) {
@@ -84,6 +92,7 @@ class _ImagePickerExampleState extends State<ImagePickerExample> {
 
     setState(() {
       _uploading = false;
+      _uploadingPercentage = 0.0;
     });
   }
 

lib/src/cloudinary_public.dart

@@ -1,12 +1,15 @@
+import 'dart:async';
 import 'dart:convert';
 
 import 'package:cloudinary_public/cloudinary_public.dart';
 import 'package:cloudinary_public/src/exceptions/cloudinary_exception.dart';
+import 'package:cloudinary_public/src/progress_callback.dart';
 import 'package:flutter/foundation.dart';
 import 'package:http/http.dart' as http;
 
 import './cloudinary_response.dart';
 import '../cloudinary_public.dart';
+import 'multipart_request.dart';
 
 /// The base class for this package
 class CloudinaryPublic {
@@ -62,6 +65,7 @@ class CloudinaryPublic {
   Future<CloudinaryResponse> uploadFile(
     CloudinaryFile file, {
     String? uploadPreset,
+    ProgressCallback? onSendProgress,
   }) async {
     if (cache) {
       assert(file.identifier != null, 'identifier is required for caching');
@@ -74,9 +78,12 @@ class CloudinaryPublic {
         '${describeEnum(file.resourceType).toLowerCase()}'
         '/upload';
 
-    final request = http.MultipartRequest(
+    final request = MultipartRequest(
       'POST',
       Uri.parse(url),
+      onProgress: (count, total) {
+        onSendProgress?.call(count, total);
+      },
     );
 
     request.headers.addAll({
@@ -147,8 +154,13 @@ class CloudinaryPublic {
   Future<CloudinaryResponse> uploadFutureFile(
     Future<CloudinaryFile> file, {
     String? uploadPreset,
+    ProgressCallback? onSendProgress,
   }) async {
-    return uploadFile(await file, uploadPreset: uploadPreset);
+    return uploadFile(
+      await file,
+      uploadPreset: uploadPreset,
+      onSendProgress: onSendProgress,
+    );
   }
 
   /// Upload multiple files using simultaneously [uploadFutureFile]

lib/src/multipart_request.dart

@@ -0,0 +1,36 @@
+import 'dart:async';
+
+import 'package:http/http.dart' as http;
+
+class MultipartRequest extends http.MultipartRequest {
+  /// Creates a new [MultipartRequest].
+  MultipartRequest(
+    String method,
+    Uri url, {
+    this.onProgress,
+  }) : super(method, url);
+
+  final void Function(int bytes, int totalBytes)? onProgress;
+
+  /// Freezes all mutable fields and returns a
+  /// single-subscription [http.ByteStream]
+  /// that will emit the request body.
+  @override
+  http.ByteStream finalize() {
+    final byteStream = super.finalize();
+    if (onProgress == null) return byteStream;
+
+    final total = contentLength;
+    var bytes = 0;
+
+    final t = StreamTransformer.fromHandlers(
+      handleData: (List<int> data, EventSink<List<int>> sink) {
+        bytes += data.length;
+        onProgress?.call(bytes, total);
+        sink.add(data);
+      },
+    );
+    final stream = byteStream.transform(t);
+    return http.ByteStream(stream);
+  }
+}

lib/src/progress_callback.dart

@@ -0,0 +1 @@
+typedef ProgressCallback = void Function(int count, int total);

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.6.1"
+    version: "2.8.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -28,7 +28,7 @@ packages:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.1"
   clock:
     dependency: transitive
     description:
@@ -87,7 +87,7 @@ packages:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0"
+    version: "1.7.0"
   path:
     dependency: transitive
     description:
@@ -148,7 +148,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0"
+    version: "0.4.2"
   typed_data:
     dependency: transitive
     description: