owlnext-dropzone #

Owlnext dropzone wrapper

FileUtils.downloadFile() -> Breaking change on web #

if you want to use FileUtils.downloadFile() on web context, you will need to inject a specific behavior from your app. create a file in your app, loaded only in library.html context (web) and call

import 'dart:convert';
import 'package:flutter/foundation.dart';
import 'package:universal_html/html.dart';
import 'package:owlnext_dropzone/owlnext_dropzone.dart';

/// Utility to enable file downloads on Flutter Web when using `owlnext_dropzone`.
///
/// # Why
/// By default, `owlnext_dropzone` cannot handle web downloads without
/// depending on `universal_html`. This class injects a web-only implementation
/// so your app controls the download behavior.
///
/// # How
/// - Call [InitWebDownload.setup] in `main.dart`.
/// - On Web, it registers a custom download function that:
///   1. Encodes file bytes to Base64
///   2. Creates a temporary `<a>` element with a `data:` URI
///   3. Triggers the browser’s native download
///   4. Cleans up the element
///
/// # Example
/// ```dart
/// void main() {
///   InitWebDownload.setup();
///   runApp(MyApp());
/// }
/// ```
class InitWebDownload {
  static void setup() {
    if (kIsWeb) {
      DownloadFileWebBypass().setDownloadFileWebFunction(_downloadFileWebImplementation);
    }
  }

  Future<void> _downloadFileWebImplementation(Uint8List bytes, String fileName, String extension) async {
    final base64 = base64Encode(bytes);
    final anchor = AnchorElement(href: 'data:application/octet-stream;base64,$base64')
      ..target = 'blank'
      ..download = fileName;
    document.body?.append(anchor);
    anchor.click();
    anchor.remove();
  }
}

Pasting from clipboard #

to continue to be able to paste file from clipboard on dropzone (except in web context), add this in your main.dart

InitPasteFromClipboardInjection.setup();

Here is an implementation of the injection using super_clipboard: ^0.9.1

import 'package:flutter/foundation.dart';
import 'package:owlnext_dropzone/owlnext_dropzone.dart';
import 'package:super_clipboard/super_clipboard.dart';

class InitPasteFromClipboardInjection {
  static void setup() {
    ClipboardFilesBypass().setGetClipboardFunction(_getClipboardFilesFromSuperClipboard);
  }

  static Future<List<({Uint8List bytes, String extension})>> _getClipboardFilesFromSuperClipboard() async {
    try {
      final clipboard = SystemClipboard.instance!;
      if (kDebugMode) print("reading clipboard");

      final reader = await clipboard.read();
      final results = <({Uint8List bytes, String extension})>[];

      // Formats pris en charge
      final formats = <SimpleFileFormat, String>{
        Formats.png: 'png',
        Formats.jpeg: 'jpeg',
        Formats.zip: 'zip',
        Formats.pdf: 'pdf',
        Formats.doc: 'doc',
        Formats.docx: 'docx',
        Formats.xlsx: 'xlsx',
        Formats.xls: 'xls',
        Formats.mp4: 'mp4',
        Formats.mov: 'mov',
      };

      final futures = <Future<void>>[];

      for (final entry in formats.entries) {
        final future = Future<void>(() {
          final completer = Completer<void>();

          // Lance la lecture
          reader.getFile(entry.key, (DataReaderFile file) async {
            if (kDebugMode) print("Got a file of type ${entry.key}");
            final bytes = await file.readAll();
            results.add((bytes: bytes, extension: entry.value));
            if (kDebugMode) print("File added to results (${results.length})");
            completer.complete();
          });

          // Timeout court pour gérer le cas où aucun fichier n’est trouvé
          Future.delayed(const Duration(milliseconds: 50), () {
            if (!completer.isCompleted) completer.complete();
          });

          return completer.future;
        });

        futures.add(future);
      }

      await Future.wait(futures);

      if (kDebugMode) print("returning ${results.length} results");

      return results;
    } catch (e, s) {
      if (kDebugMode) {
        print("Error _getClipboardFilesFromSuperClipboard: $e");
        print("Trace _getClipboardFilesFromSuperClipboard: $s");
      }
      rethrow;
    }
  }
}

Debugging #

to see debug messages (in debugModeOnly), put this in your app main.dart

OwlnextDropzoneDebuger.kDebugOwlnextDropzone = true;