how to deploy flutter in azure app services

Below are the steps for deploying a Flutter web application to Azure App Services using Azure Static Web Apps:

• Make sure Flutter is installed and configured.

Enable Web Support:

You need to run the following commands to use the beta channel and enable web support:

flutter channel beta  
flutter upgrade  
flutter config --enable-web

• Use the flutter create command to generate a new Flutter web project:

flutter create my_flutter_web_app

• Go into your project directory and use the flutter build web command to compile:

cd my_flutter_web_app
flutter build web

• Use the command below to run your Flutter web application in a Chrome browser:

flutter run -d chrome

• Add staticwebapp.config.json in the root path (or) in my_flutter_web_app:

{
  "navigationFallback": {
    "rewrite": "index.html"
  }
}

• Make sure to install Node.js, Azure Functions Core Tools, and Azure Static Web Apps CLI, and then install the following NPM packages:

npm install -g azure-functions-core-tools

npm install -g @azure/static-web-apps-cli

• Use the swa init command to set up the configuration for deploying your app to Azure Static Web Apps:

swa init

• Check swa-cli.config.json in the root path:

{
  "$schema": "https://aka.ms/azure/static-web-apps-cli/schema",
  "configurations": {
    "my-flutter-web-app": {
      "appLocation": ".",
      "outputLocation": "build\\web",
      "appBuildCommand": "flutter build web",
      "run": "flutter run -d edge --web-port 8080 ",
      "appDevserverUrl": "http://localhost:8080"
    }
  }
}

• Use the swa build command to build your Flutter web app in preparation for deployment.

• Use the swa deploy command to deploy your app to Azure App Services using Azure Static Web Apps.

• Install the packages below:

dart pub global activate flutter_cors
flutter pub add http

The below sample Flutter web GUI code connects to Azure Blob Storage using a SAS URL and visualizes data in the UI:

lib/main.dart:

import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:async';
import 'dart:typed_data';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: alt(),
    );
  }
}

class alt extends StatefulWidget {
  const alt({Key? key}) : super(key: key);

  @override
  _altState createState() => _altState();
}

class _altState extends State<alt> {
  String? fetchedData;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Fetch Blob Data'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              onPressed: () async {
                await fetchData();
              },
              child: const Text('Fetch Blob Data'),
            ),
            SizedBox(height: 20),
            fetchedData != null
                ? Expanded(
                    child: SingleChildScrollView(
                      child: Padding(
                        padding: const EdgeInsets.all(16.0),
                        child: Text(
                          fetchedData!,
                          style: TextStyle(fontSize: 16),
                        ),
                      ),
                    ),
                  )
                : Container(),
          ],
        ),
      ),
    );
  }

  Future<void> fetchData() async {
    String sasUrl =
        'https://example.blob.core.windows.net/container/HelloWorld.txt?sp=r&st=2024-03-29T15:29:53Z&se=2024-03-29T23:29:53Z&sv=2022-11-02&sr=b&sig=SampleSignature
';

    try {
      // Send HTTP GET request to the SAS URL
      final response = await http.get(Uri.parse(sasUrl));

      if (response.statusCode == 200) {
        // Parse response body as bytes
        Uint8List bytes = response.bodyBytes;

        // Handle the data as needed
        // For example, you can decode the bytes to a string or save them to a file
        print('Received ${bytes.length} bytes of data.');

        // Example: Decode bytes to a string
        String data = String.fromCharCodes(bytes);
        setState(() {
          fetchedData = data;
        });
      } else {
        print('Failed to fetch data: ${response.statusCode}');
      }
    } catch (e) {
      print('Error fetching data: $e');
    }
  }
}

Azure Storage:

• Add CORS in the Azure portal for storage.

• Make that the application is built and run.

• Use swa build and swa deploy to build and deploy to Azure.