CacheManager attempts to create file named guid.* on Windows (full example included and clear description)

La lógica sospechada está en lib/src/web/file_service.dart, alrededor de la línea 115; empieza ejecutando la reproducción mínima proporcionada en Windows y siguiendo cómo el encabezado content-type se convierte en la extensión del nombre de archivo de la caché. Se considera terminado cuando las descargas cuyos encabezados no proporcionan una extensión utilizable crean un nombre de archivo válido en Windows, mientras que las extensiones normales siguen funcionando.

🐛 Bug Report

While downloading an image from a webserver the cache manager decides to create a filename ending with .* which is not permitted on windows.

Expected behavior

Create a filename without extension or a generic extension like .cache or .file since the cache manager cannot determine it from the webserver headers.

Reproduction steps

i have made minimal reproducible example no external dependencies needed (other than http package)
i am aware that the server should provide correct descriptive headers for the content being served but sometimes it happens not to in some scenarios.

import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import 'package:http/http.dart' as http;
import 'package:http/testing.dart';

Future<void> main() async {
  final client = MockClient((http.Request request) async =>
      http.Response("a png image", 200, headers: {
        "content-type": "application/*",
        "content-disposition":
            "attachment; filename=file; filename*=UTF-8''file"
      }));

  final cmgr = CacheManager(Config(DefaultCacheManager.key,
      fileService: HttpFileService(httpClient: client)));

/* crashes with
  Launching lib\main.dart on Windows in debug mode...
  √  Built build\windows\runner\Debug\cache_mgr_test.exe.
  [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: FileSystemException: Cannot open file, path = 'C:\Users\csman\AppData\Local\Temp\libCachedImageData\cf09f070-6cef-1d8a-b096-2334712b3134.*' (OS Error: The filename, directory name, or volume label syntax is incorrect.

  , errno = 123)
  #0      _checkForErrorResponse (dart:io/common.dart:55:9)
  #1      _File.open.<anonymous closure> (dart:io/file_impl.dart:381:7)
  <asynchronous suspension>
*/

  await cmgr.downloadFile("http://myaddress.com/imageManager?pngfileid=1234");
}

/*
pubspec.yaml 

name: cache_mgr_test
description: A new Flutter project.
publish_to: "none"
version: 1.0.0+1
environment:
  sdk: ">=3.1.5 <4.0.0"
dependencies:
  cupertino_icons: ^1.0.2
  flutter:
    sdk: flutter
  flutter_cache_manager: ^3.3.1
  http: ^1.1.0
dev_dependencies:
  flutter_lints: ^2.0.0
  flutter_test:
    sdk: flutter
flutter:
  uses-material-design: true
*/

Configuration

Version: 3.3.1

Platform:
Windows 10

I think the problematic part is in \flutter_cache_manager-3.3.1\lib\src\web\file_service.dart line 115 around

  @override
  String get fileExtension {
    var fileExtension = '';
    final contentTypeHeader = _header(HttpHeaders.contentTypeHeader);
    if (contentTypeHeader != null) {
      final contentType = ContentType.parse(contentTypeHeader);
      fileExtension = contentType.fileExtension;
    }
    return fileExtension;
  }