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Use tokens

Updated

Retrieve tokens generated by an authentication token server to securely connect to Agora.

To protect your business, it is best practice to authenticate every client that joins a channel. This guide explains how to fetch an authentication token from your token server, use it to join a channel, and renew the token when it expires.

Understand the tech

When a user attempts to connect to an Agora channel, your app retrieves a token from the token server in your security infrastructure. Your app then sends this token to Agora SDRTN® for authentication. Agora SDRTN® reads the information stored in the token to validate the request.

The following figure shows the call flow you implement to create step-up-authentication with Agora Interactive Live Streaming:

Token authentication flow

Prerequisites

Before starting, ensure that you have:

Implement basic authentication

This section shows you how to implement basic authentication by acquiring a token and using it to join a channel.

Use a token to join a channel

This section shows you how to integrate token authentication in your app.

  1. Add the following to the pubspec.yaml file, under dependencies:

    dependencies:
  # Agora Flutter SDK, use the latest version of agora_rtc_engine
  agora_rtc_engine: ^6.3.0
  # For making http requests
  http: ^0.13.5

  2. Replace the contents in /lib/main.dart with the following code.

Sample code for basic authentication

  import 'dart:convert';

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

    void main() => runApp(const MyApp());

    /// This widget is the root of your application.
    class MyApp extends StatefulWidget {
    /// Construct the [MyApp]
    const MyApp({Key? key}) : super(key: key);

    @override
    State<MyApp> createState() => _MyAppState();
    }

    class _MyAppState extends State<MyApp> {

    @override
    Widget build(BuildContext context) {
      return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(
          title: const Text('APIExample'),
        ),
        body: const JoinChannelVideoToken()),
      );
    }
    }

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

    @override
    State<StatefulWidget> createState() => _State();
    }

    class _State extends State<JoinChannelVideoToken> {
    late final RtcEngine _engine;
    bool _isReadyPreview = false;

    bool isJoined = false, switchCamera = true, switchRender = true;
    Set<int> remoteUid = {};
    static const String appId = '<Your app ID>'; // Fill in the information from Agora console
    static const String channelId = '<Your channel name>'; // Fill in the channel name
    static const String hostUrl = '<Your host URL and port>'; // Fill in the server URL and port

    @override
    void initState() {
      super.initState();
      _initEngine();
    }

    @override
    void dispose() {
      super.dispose();
      _dispose();
    }

    Future<void> _dispose() async {
      await _engine.leaveChannel();
      await _engine.release();
    }

    Future<void> _initEngine() async {
      _engine = createAgoraRtcEngine();
      await _engine.initialize(const RtcEngineContext(
      appId: appId,
      ));

      _engine.registerEventHandler(RtcEngineEventHandler(
      onJoinChannelSuccess: (RtcConnection connection, int elapsed) {
        setState(() {
        isJoined = true;
        });
      },
      onUserJoined: (RtcConnection connection, int rUid, int elapsed) {
        setState(() {
        remoteUid.add(rUid);
        });
      },
      onUserOffline:
        (RtcConnection connection, int rUid, UserOfflineReasonType reason) {
        setState(() {
        remoteUid.removeWhere((element) => element == rUid);
        });
      },
      onLeaveChannel: (RtcConnection connection, RtcStats stats) {
        setState(() {
        isJoined = false;
        remoteUid.clear();
        });
      },
      onTokenPrivilegeWillExpire: (RtcConnection connection, String token) {
        _fetchToken(1234, channelId, 1, false);
      },
      onRequestToken: (RtcConnection connection) {
        _fetchToken(1234, channelId, 1, true);
      },
      ));

      await _engine.enableVideo();

      await _engine.startPreview();
      await _fetchToken(1234, channelId, 1, true);

      setState(() {
      _isReadyPreview = true;
      });
    }

    Future<void> _fetchToken(
      int uid,
      String channelName,
      int toeknRole,
      bool needJoinChannel,
    ) async {
      var client = http.Client();
      try {
      Map<String, String> headers = {
        'Content-type': 'application/json',
        'Accept': 'application/json',
      };

      var response = await client.post(Uri.parse(hostUrl),
        headers: headers,
        body: jsonEncode(
          {'uid': uid, 'ChannelName': channelName, 'role': toeknRole}));
      var decodedResponse = jsonDecode(utf8.decode(response.bodyBytes)) as Map;

      final token = decodedResponse['token'];
      if (needJoinChannel) {
        await _engine.joinChannel(
        token: token,
        channelId: channelName,
        uid: uid,
        options: const ChannelMediaOptions(
          channelProfile: ChannelProfileType.channelProfileLiveBroadcasting,
          clientRoleType: ClientRoleType.clientRoleBroadcaster,
        ),
        );
      } else {
        await _engine.renewToken(token);
      }
      } finally {
      client.close();
      }
    }

    @override
    Widget build(BuildContext context) {
      if (!_isReadyPreview) return Container();
      return Stack(
      children: [
        AgoraVideoView(
        controller: VideoViewController(
          rtcEngine: _engine,
          canvas: const VideoCanvas(uid: 0),
        ),
        ),
        Align(
        alignment: Alignment.topLeft,
        child: SingleChildScrollView(
          scrollDirection: Axis.horizontal,
          child: Row(
          children: List.of(remoteUid.map(
            (e) => SizedBox(
            width: 120,
            height: 120,
            child: AgoraVideoView(
              controller: VideoViewController.remote(
              rtcEngine: _engine,
              canvas: VideoCanvas(uid: e),
              connection: const RtcConnection(channelId: channelId),
              ),
            ),
            ),
          )),
          ),
        ),
        )
      ],
      );
    }
    }

Replace <Your app ID> with your app ID, which must be consistent with the app ID you specified in the server configuration. Update <Your host URL and port> with the host URL and port of the local Golang server you have deployed. For example 99.9.9.99:8082.

The sample code implements the following logic:

  • Calls joinChannel to join a channel using the user ID, the channel name, and a token you obtain from the server. The user ID and channel name you specify must be consistent with the values you used to generate the token.

  • The SDK triggers an onTokenPrivilegeWillExpire callback 30 seconds before the token expires. After receiving the callback, you obtain a new token from the server and call renewToken to pass the newly generated token to the SDK.

  • If the token expires, the SDK triggers an onRequestToken callback. After receiving the callback, obtain a new token from the server and call joinChannel with the new token to rejoin the channel.

Build and run the project on the local device, the app performs the following operations:

  • Obtains a token from your token server.
  • Joins the channel.
  • Automatically renews the token when it is about to expire.

The user ID and channel name used to join a channel must be consistent with the values used to generate the token.

Reference

This section contains content that completes the information on this page, or points you to documentation that explains other aspects to this product.

API reference

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