PROPOSAL: Improve experience when retrying MultiPart request with Files

generator/lib/src/generator.dart

@@ -984,7 +984,7 @@ You should create a new class to encapsulate the response.
             mapperVal = '''
     (json)=> json is List<dynamic>
           ? json
-            .map<$genericTypeString>((i) => 
+            .map<$genericTypeString>((i) =>
                   i as $genericTypeString
                 )
             .toList()
@@ -1258,13 +1258,13 @@ You should create a new class to encapsulate the response.
             if (baseUrl == null || baseUrl.trim().isEmpty) {
               return dioBaseUrl;
             }
-            
+
             final url = Uri.parse(baseUrl);
-            
+
             if (url.isAbsolute) {
               return url.toString();
             }
-            
+
             return Uri.parse(dioBaseUrl).resolveUri(url).toString();
           ''');
       });
@@ -1732,21 +1732,29 @@ ${bodyName.displayName} == null
         final contentType = r.peek('contentType')?.stringValue;
 
         if (isFileField) {
+          final keepFilePath = r.peek('keepFilePath')?.boolValue ?? false;
           final fileNameValue = r.peek('fileName')?.stringValue;
           final fileName = fileNameValue != null
               ? literalString(fileNameValue)
               : refer(p.displayName)
                   .property('path.split(Platform.pathSeparator).last');
+          final filePath = refer(p.displayName).property('path');
+          final headers = keepFilePath
+              ? literalMap({
+                  'original_file_path': literalList([filePath])
+                })
+              : literalMap({});
 
           final uploadFileInfo = refer('$MultipartFile.fromFileSync').call([
-            refer(p.displayName).property('path')
+            filePath
           ], {
             'filename': fileName,
             if (contentType != null)
               'contentType':
                   refer('MediaType', 'package:http_parser/http_parser.dart')
                       .property('parse')
-                      .call([literal(contentType)])
+                      .call([literal(contentType)]),
+            'headers': headers,
           });
 
           final optionalFile = m.parameters
@@ -1789,7 +1797,7 @@ ${bodyName.displayName} == null
                 MultipartFile.fromBytes(${p.displayName},
 
                 filename:${literal(fileName)},
-                    $conType
+                    $conType,
                     ))
                   ''')
           ]).statement;
@@ -1823,7 +1831,7 @@ ${bodyName.displayName} == null
                 '$fieldName',
                 MultipartFile.fromBytes(i,
                     filename:${literal(fileName)},
-                    $conType
+                    $conType,
                     )))
                   ''')
               ]).statement,
@@ -1851,6 +1859,13 @@ ${bodyName.displayName} == null
             final conType = contentType == null
                 ? ''
                 : 'contentType: MediaType.parse(${literal(contentType)}),';
+            final keepFilePath = r.peek('keepFilePath')?.boolValue ?? false;
+            final filePath = refer(p.displayName).property('path');
+            final headers = keepFilePath
+                ? literalMap({
+                    'original_file_path': [filePath]
+                  })
+                : '{}';
             if (p.type.isNullable) {
               blocks.add(Code('if (${p.displayName} != null) {'));
             }
@@ -1861,7 +1876,8 @@ ${bodyName.displayName} == null
                 '$fieldName',
                 MultipartFile.fromFileSync(i.path,
                     filename: i.path.split(Platform.pathSeparator).last,
-                    $conType
+                    $conType,
+                    headers: $headers,
                     )))
                   ''')
               ]).statement,

generator/pubspec.yaml

@@ -17,7 +17,8 @@ dependencies:
   code_builder: ^4.4.0
   dart_style: ^2.3.0
   dio: ^5.0.0
-  retrofit: ^4.0.1
+  retrofit:  ## update this dependency once a new version is released with keepOriginalPath change
+    path: ../retrofit
   source_gen: ^1.3.0
   tuple: ^2.0.1
 

generator/test/src/generator_test_src.dart

@@ -263,6 +263,9 @@ enum ImageType { icon, large }
       MultipartFile.fromFileSync(
         image.path,
         filename: image.path.split(Platform.pathSeparator).last,
+        headers: {
+          'original_file_path': [image.path]
+        },
       ),
     ));
 ''',
@@ -271,7 +274,7 @@ enum ImageType { icon, large }
 @RestApi(baseUrl: 'https://httpbin.org/')
 abstract class FilePartTest {
   @POST('/profile')
-  Future<String> setProfile(@Part() File image);
+  Future<String> setProfile(@Part(keepFilePath: true) File image);
 }
 
 @ShouldGenerate(
@@ -282,6 +285,7 @@ abstract class FilePartTest {
       MultipartFile.fromFileSync(
         image.path,
         filename: 'my_profile_image.jpg',
+        headers: {},
       ),
     ));
 ''',
@@ -320,7 +324,8 @@ abstract class FilePartWithMultipartListTest {
 @RestApi(baseUrl: 'https://httpbin.org/')
 abstract class FilePartWithNullableMultipartListTest {
   @POST('/profile')
-  Future<String> setProfile(@Part() List<MultipartFile>? images);
+  Future<String> setProfile(
+      @Part(keepFilePath: true) List<MultipartFile>? images);
 }
 
 @ShouldGenerate(
@@ -331,6 +336,9 @@ abstract class FilePartWithNullableMultipartListTest {
       MultipartFile.fromFileSync(
         image.path,
         filename: image.path.split(Platform.pathSeparator).last,
+        headers: {
+          'original_file_path': [image.path]
+        },
       ),
     ));
   ''',
@@ -339,7 +347,7 @@ abstract class FilePartWithNullableMultipartListTest {
 @RestApi(baseUrl: 'https://httpbin.org/')
 abstract class UploadFileInfoPartTest {
   @POST('/profile')
-  Future<String> setProfile(@Part() File image);
+  Future<String> setProfile(@Part(keepFilePath: true) File image);
 }
 
 @ShouldGenerate(
@@ -940,6 +948,7 @@ abstract class TestHttpResponseArray {
         MultipartFile.fromFileSync(
           i.path,
           filename: i.path.split(Platform.pathSeparator).last,
+          headers: {},
         ))));
 ''',
   contains: true,
@@ -953,6 +962,7 @@ abstract class TestHttpResponseArray {
           MultipartFile.fromFileSync(
             i.path,
             filename: i.path.split(Platform.pathSeparator).last,
+            headers: {},
           ))));
     }
 ''',
@@ -966,6 +976,7 @@ abstract class TestHttpResponseArray {
         MultipartFile.fromFileSync(
           file.path,
           filename: file.path.split(Platform.pathSeparator).last,
+          headers: {},
         ),
       ));
     }

retrofit/lib/http.dart

@@ -301,6 +301,7 @@ class Part {
     this.name,
     this.fileName,
     this.contentType,
+    this.keepFilePath = false,
   });
 
   @Deprecated('future release')
@@ -313,6 +314,9 @@ class Part {
 
   // To identify the content type of a file
   final String? contentType;
+
+  /// If this field is a file, optionally specify whether to keep the file path for retrying requests
+  final bool? keepFilePath;
 }
 
 @immutable