Gallery/lib/data_provider/ssh_data_provider.dart

import 'dart:io';

import 'package:dartssh2/dartssh2.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:gallery/data_provider/data_provider.dart';

import 'dart:ui' as ui show Codec, ImmutableBuffer;

import 'package:path_provider/path_provider.dart';

class SSHDataProvider extends DataProvider {
  final Future<String> host;
  final Future<int> port;
  final Future<String> username;
  final Future<String> password;
  final Future<String> initialPath;

  SftpClient? sftpClient;
  SSHClient? sshClient;

  SSHDataProvider(
      {required this.host,
      required this.port,
      required this.initialPath,
      required this.password,
      required this.username});

  @override
  Future<void> connect() async {
    if (sshClient != null && !sshClient!.isClosed) return;

    sshClient = SSHClient(
      await SSHSocket.connect(await host, await port),
      username: await username,
      onPasswordRequest: () => password,
    );
    await sshClient?.authenticated;

    sftpClient = await sshClient?.sftp();
  }

  @override
  Future<Folder> listOfFiles({Uri? uri}) async {
    await connect();
    if (sftpClient == null) throw const FormatException("");

    final dir =
        uri != null ? Directory.fromUri(uri) : Directory(await initialPath);

    final items = await sftpClient!.listdir(dir.path);
    List<Item> res = [];
    for (final val in items) {
      if (val.filename == "." || val.filename == "..") continue;

      if (validSuffix.any((suff) => val.filename.endsWith(suff))) {
        res.add(Item(false, Uri.file(dir.path + val.filename), val.filename));
      } else if (val.attr.isDirectory) {
        res.add(
            Item(true, Uri.directory(dir.path + val.filename), val.filename));
      }
    }

    res.sort(
      (a, b) => b.isFolder ? 1 : -1,
    );

    return Folder(res, dir.uri, dir.parent.uri);
  }

  @override
  ImageProvider getImageProvider(Uri uri) {
    return _SSHImageProvider(uri, sftpClient!);
  }
}

class _SSHImageProvider extends ImageProvider<_SSHImageProvider> {
  const _SSHImageProvider(this.uri, this.sftpClient);

  final Uri uri;
  final SftpClient sftpClient;

  @override
  Future<_SSHImageProvider> obtainKey(ImageConfiguration configuration) {
    return SynchronousFuture<_SSHImageProvider>(this);
  }

  @override
  ImageStreamCompleter loadBuffer(
      _SSHImageProvider key, DecoderBufferCallback decode) {
    return MultiFrameImageStreamCompleter(
      codec: _loadAsync(key, decode),
      scale: 1.0,
      debugLabel: key.uri.path,
      informationCollector: () => <DiagnosticsNode>[
        ErrorDescription('Path: ${uri.path}'),
      ],
    );
  }

  Future<ui.Codec> _loadAsync(
      _SSHImageProvider key, DecoderBufferCallback decode) async {
    assert(key == this);

    Directory tempDir = await getTemporaryDirectory();
    String tempPath = "${tempDir.path}/gallery";
    // check if temp file exists
    Uint8List bytes;
    final File tmpPic = File(tempPath + uri.toFilePath());
    if (await tmpPic.exists()) {
      // use temp file
      bytes = await tmpPic.readAsBytes();
    } else {
      final file = await sftpClient.open(uri.toFilePath());
      bytes = await file.readBytes();
      await tmpPic.create(recursive: true);
      await tmpPic.writeAsBytes(bytes);
    }

    if (bytes.lengthInBytes == 0) {
      // The file may become available later.
      PaintingBinding.instance.imageCache.evict(key);
      throw StateError(
          'bytes are empty is empty and cannot be loaded as an image.');
    }

    return decode(await ui.ImmutableBuffer.fromUint8List(bytes));
  }

  @override
  bool operator ==(Object other) {
    if (other.runtimeType != runtimeType) {
      return false;
    }
    return other is _SSHImageProvider && other.uri.path == uri.path;
  }

  @override
  int get hashCode => uri.path.hashCode;

  @override
  String toString() => '${objectRuntimeType(this, 'FileImage')}("${uri.path}")';
}