add ability to download scanned files directly to the end device (#17)

app/lib/pages/home.dart

@@ -1,5 +1,10 @@
+import 'dart:io';
+
 import 'package:dio/dio.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:open_file/open_file.dart';
+import 'package:path_provider/path_provider.dart';
 import 'package:photosmarter/components/scan_options.dart';
 import 'package:photosmarter/extensions/string_formatting.dart';
 import 'package:photosmarter/models/scan_result.dart';
@@ -22,8 +27,10 @@ class HomePage extends StatefulWidget {
 class _HomePageState extends State<HomePage> {
   bool _isScanning = false;
 
-  Future<ScanResult> _scan(
-      String baseUrl, String fileName, OptionsProvider optionsProvider) async {
+  Future<Response<dynamic>> _scan(String fileName) async {
+    final optionsProvider = context.read<OptionsProvider>();
+    final settingsProvider = context.read<SettingsProvider>();
+
     final formData = FormData.fromMap({
       'type': optionsProvider.type.name.toUpperCase(),
       'dimension': optionsProvider.dimension.name.capitalize(),
@@ -34,21 +41,31 @@ class _HomePageState extends State<HomePage> {
     });
 
     final response = await dio.post(
-      '$baseUrl/api/scan',
+      '${settingsProvider.baseUrl}/api/scan',
+      options: Options(
+        headers: {
+          'Accept': settingsProvider.directDownload
+              ? 'application/pdf, image/jpeg'
+              : 'application/json',
+        },
+        responseType: settingsProvider.directDownload
+            ? ResponseType.bytes
+            : ResponseType.json,
+      ),
       data: formData,
     );
 
-    return ScanResult.fromJson(response.data);
+    return response;
   }
 
-  SnackBar _createSnackBar(
+  void _showSnackBar(
     String content, {
     Color? backgroundColor,
     Color? textColor,
     Duration? duration,
     SnackBarAction? action,
   }) {
-    return SnackBar(
+    ScaffoldMessenger.of(context).showSnackBar(SnackBar(
       content: Text(content, style: TextStyle(color: textColor)),
       backgroundColor: backgroundColor,
       padding: const EdgeInsets.symmetric(
@@ -61,7 +78,7 @@ class _HomePageState extends State<HomePage> {
       ),
       duration: duration ?? const Duration(seconds: 5),
       action: action,
-    );
+    ));
   }
 
   Future<String?> _promptFileName() async {
@@ -103,10 +120,48 @@ class _HomePageState extends State<HomePage> {
     return fileName?.text;
   }
 
+  Future<void> _saveFileLocally(Response<dynamic> response) async {
+    final theme = Theme.of(context);
+
+    final safeFileName =
+        response.headers['x-photosmarter-filename']?.firstOrNull;
+    if (safeFileName == null) {
+      _showSnackBar(
+        'No file name provided by server',
+        backgroundColor: theme.colorScheme.errorContainer,
+        textColor: theme.colorScheme.onErrorContainer,
+      );
+      return;
+    }
+
+    final dir = await getApplicationDocumentsDirectory();
+    final file = File('${dir.path}/$safeFileName');
+    if (await file.exists()) {
+      _showSnackBar(
+        'File $safeFileName already exists',
+        backgroundColor: theme.colorScheme.errorContainer,
+        textColor: theme.colorScheme.onErrorContainer,
+      );
+      return;
+    }
+    await file.writeAsBytes(response.data);
+
+    _showSnackBar(
+      'File saved as $safeFileName',
+      backgroundColor: theme.colorScheme.primaryContainer,
+      textColor: theme.colorScheme.onPrimaryContainer,
+      action: SnackBarAction(
+        label: 'Open',
+        textColor: theme.colorScheme.onPrimaryContainer,
+        // TODO: why can the file not be opened?
+        onPressed: () => OpenFile.open(file.path),
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     final settingsProvider = context.watch<SettingsProvider>();
-    final messenger = ScaffoldMessenger.of(context);
     final theme = Theme.of(context);
 
     return Scaffold(
@@ -137,7 +192,7 @@ class _HomePageState extends State<HomePage> {
           child: FloatingActionButton.extended(
             onPressed: !_isScanning
                 ? () async {
-                    final optionsProvider = context.read<OptionsProvider>();
+                    await HapticFeedback.heavyImpact();
 
                     final fileName = await _promptFileName();
                     if (fileName == null) {
@@ -149,44 +204,45 @@ class _HomePageState extends State<HomePage> {
                     });
 
                     try {
-                      final result = await _scan(
-                          settingsProvider.baseUrl, fileName, optionsProvider);
+                      final response = await _scan(fileName);
 
-                      messenger.showSnackBar(
-                        _createSnackBar(
+                      if (settingsProvider.directDownload) {
+                        await _saveFileLocally(response);
+                      } else {
+                        final result = ScanResult.fromJson(response.data);
+                        _showSnackBar(
                           result.message,
                           backgroundColor: result.success
                               ? theme.colorScheme.primaryContainer
                               : theme.colorScheme.errorContainer,
                           textColor: result.success
                               ? theme.colorScheme.onPrimaryContainer
                               : theme.colorScheme.onErrorContainer,
-                        ),
-                      );
+                        );
+                      }
+
+                      await HapticFeedback.vibrate();
                     } catch (error) {
-                      messenger.showSnackBar(
-                        _createSnackBar(
-                          'Scan failed, is the address correct?',
-                          backgroundColor: theme.colorScheme.errorContainer,
-                          textColor: theme.colorScheme.onErrorContainer,
-                          action: SnackBarAction(
-                              label: 'Details',
-                              textColor: theme.colorScheme.onErrorContainer,
-                              onPressed: () => showDialog<TextEditingValue?>(
-                                  context: context,
-                                  builder: (BuildContext context) {
-                                    return AlertDialog(
-                                      content: Text(error.toString()),
-                                      actions: <Widget>[
-                                        TextButton(
-                                          onPressed: () =>
-                                              Navigator.pop(context),
-                                          child: const Text('OK'),
-                                        ),
-                                      ],
-                                    );
-                                  })),
-                        ),
+                      _showSnackBar(
+                        'Scan failed, is the address correct?',
+                        backgroundColor: theme.colorScheme.errorContainer,
+                        textColor: theme.colorScheme.onErrorContainer,
+                        action: SnackBarAction(
+                            label: 'Details',
+                            textColor: theme.colorScheme.onErrorContainer,
+                            onPressed: () => showDialog<TextEditingValue?>(
+                                context: context,
+                                builder: (BuildContext context) {
+                                  return AlertDialog(
+                                    content: Text(error.toString()),
+                                    actions: <Widget>[
+                                      TextButton(
+                                        onPressed: () => Navigator.pop(context),
+                                        child: const Text('OK'),
+                                      ),
+                                    ],
+                                  );
+                                })),
                       );
                     } finally {
                       setState(() {

app/lib/pages/settings.dart

@@ -10,12 +10,15 @@ class SettingsPage extends StatefulWidget {
 }
 
 class _SettingsPageState extends State<SettingsPage> {
-  final _baseUrlTextController = TextEditingController();
+  TextEditingController? _baseUrlTextController;
 
   @override
   Widget build(BuildContext context) {
-    final settingsProvider = context.read<SettingsProvider>();
-    _baseUrlTextController.text = settingsProvider.baseUrl;
+    final settingsProvider = context.watch<SettingsProvider>();
+    if (_baseUrlTextController == null) {
+      _baseUrlTextController = TextEditingController();
+      _baseUrlTextController!.text = settingsProvider.baseUrl;
+    }
 
     return Scaffold(
       appBar: AppBar(
@@ -37,6 +40,15 @@ class _SettingsPageState extends State<SettingsPage> {
               },
             ),
           ),
+          CheckboxListTile(
+            title: const Text('Direct download'),
+            value: settingsProvider.directDownload,
+            onChanged: (value) {
+              if (value != null) {
+                settingsProvider.directDownload = value;
+              }
+            },
+          )
         ],
       ),
     );

app/lib/providers/settings_provider.dart

@@ -21,4 +21,13 @@ class SettingsProvider extends ChangeNotifier {
     prefs?.setString('baseUrl', url);
     notifyListeners();
   }
+
+  bool get directDownload {
+    return prefs?.getBool('directDownload') ?? false;
+  }
+
+  set directDownload(bool download) {
+    prefs?.setBool('directDownload', download);
+    notifyListeners();
+  }
 }

app/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -5,8 +5,10 @@
 import FlutterMacOS
 import Foundation
 
+import path_provider_foundation
 import shared_preferences_foundation
 
 func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
   SharedPreferencesPlugin.register(with: registry.registrar(forPlugin: "SharedPreferencesPlugin"))
 }

app/pubspec.lock

@@ -152,6 +152,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.0"
+  open_file:
+    dependency: "direct main"
+    description:
+      name: open_file
+      sha256: a5a32d44acb7c899987d0999e1e3cbb0a0f1adebbf41ac813ec6d2d8faa0af20
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.3.2"
   path:
     dependency: transitive
     description:
@@ -160,6 +168,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.8.3"
+  path_provider:
+    dependency: "direct main"
+    description:
+      name: path_provider
+      sha256: a1aa8aaa2542a6bc57e381f132af822420216c80d4781f7aa085ca3229208aaa
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.1"
+  path_provider_android:
+    dependency: transitive
+    description:
+      name: path_provider_android
+      sha256: "477184d672607c0a3bf68fbbf601805f92ef79c82b64b4d6eb318cbca4c48668"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.2"
+  path_provider_foundation:
+    dependency: transitive
+    description:
+      name: path_provider_foundation
+      sha256: "19314d595120f82aca0ba62787d58dde2cc6b5df7d2f0daf72489e38d1b57f2d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.1"
   path_provider_linux:
     dependency: transitive
     description:

app/pubspec.yaml

@@ -38,6 +38,8 @@ dependencies:
   shared_preferences: ^2.2.2
   provider: ^6.1.1
   dio: ^5.4.0
+  path_provider: ^2.1.1
+  open_file: ^3.3.2
 
 dev_dependencies:
   flutter_test:

src/routes/api/scan/index.ts

@@ -53,17 +53,35 @@ export async function POST({ request }: APIEvent): Promise<Response> {
     });
   }
 
-  const { data, extension } = result;
+  const { data, extension, contentType } = result;
   const safeFileName = !!preferredFileName?.trim()
     ? sanitize(preferredFileName)
     : format(new Date(), 'yyyyMMdd_HHmmss');
   const safeExtension = extension ?? 'unknown';
 
+  const fileName = safeFileName.concat(
+    !safeFileName.includes('.') ? `.${safeExtension}` : '',
+  );
+
+  // No automatic upload desired - instead download the scanned document.
+  const accept = request.headers.get('accept');
+  if (
+    accept !== null &&
+    contentType !== undefined &&
+    accept.includes(contentType)
+  ) {
+    return new Response(data, {
+      headers: new Headers({
+        'Content-Type': contentType,
+        'Content-Disposition': `attachment; filename="${fileName}"`,
+        'Content-Length': data.byteLength.toString(10),
+        'X-Photosmarter-Filename': fileName,
+      }),
+    });
+  }
+
   try {
-    const name = safeFileName.concat(
-      !safeFileName.includes('.') ? `.${safeExtension}` : '',
-    );
-    await fileService.save(name, data);
+    await fileService.save(fileName, data);
   } catch (error) {
     return json({
       success: false,

src/server/services/photosmart-service.ts

@@ -57,6 +57,7 @@ export type PhotosmartScanOptions = {
 export type PhotosmartStatus = 'Idle' | 'BusyWithScanJob';
 
 export type PhotosmartScanResult = {
+  contentType?: string;
   extension?: string;
   data: ArrayBuffer;
 };
@@ -131,6 +132,7 @@ class PhotosmartService {
     const contentType = binaryResponse.headers['content-type'];
 
     return {
+      contentType,
       extension:
         typeof contentType === 'string'
           ? extension(contentType) || undefined