add ci build and caching of sftp files

lib/data_provider/data_provider.dart

@@ -16,7 +16,6 @@ class Folder {
   Folder(this.items, this.self, this.parent);
 }
 
-
 abstract class DataProvider {
   final List<String> validSuffix = [".jpg", ".jpeg", ".png"];
 

lib/data_provider/ssh_data_provider.dart

@@ -1,5 +1,4 @@
 import 'dart:io';
-import 'dart:typed_data';
 
 import 'package:dartssh2/dartssh2.dart';
 import 'package:flutter/cupertino.dart';
@@ -8,6 +7,8 @@ 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 String host;
   final int port;
@@ -48,6 +49,8 @@ class SSHDataProvider extends DataProvider {
     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) {
@@ -56,6 +59,10 @@ class SSHDataProvider extends DataProvider {
       }
     }
 
+    res.sort(
+      (a, b) => b.isFolder ? 1 : -1,
+    );
+
     return Folder(res, dir.uri, dir.parent.uri);
   }
 
@@ -66,13 +73,8 @@ class SSHDataProvider extends DataProvider {
 }
 
 class _SSHImageProvider extends ImageProvider<_SSHImageProvider> {
-  /// Creates an object that decodes a [File] as an image.
-  ///
-  /// The arguments must not be null.
-  const _SSHImageProvider(this.uri, this.sftpClient, {this.scale = 1.0})
-      : assert(scale != null);
+  const _SSHImageProvider(this.uri, this.sftpClient, {this.scale = 1.0});
 
-  /// The file to decode into an image.
   final Uri uri;
   final SftpClient sftpClient;
 
@@ -113,14 +115,27 @@ class _SSHImageProvider extends ImageProvider<_SSHImageProvider> {
       DecoderBufferCallback? decode, DecoderCallback? decodeDeprecated) async {
     assert(key == this);
 
-    final file = await sftpClient.open(uri.toFilePath());
-    // todo do not load whole image in ram, create tempfile instead.
-    final Uint8List bytes = await file.readBytes();
+    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());
+      // todo do not load whole image in ram, create tempfile instead.
+      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('$file is empty and cannot be loaded as an image.');
+      throw StateError(
+          'bytes are empty is empty and cannot be loaded as an image.');
     }
 
     if (decode != null) {