# Use tokens (/en/realtime-media/interactive-live-streaming/build/authenticate-users/use-tokens/react-native)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

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 [#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**

    ![token authentication flow](https://assets-docs.agora.io/images/video-sdk/token-authentication.svg)

    ## Prerequisites [#prerequisites-7]

    Before starting, ensure that you have:

    * Implemented the [Quickstart](../../index.mdx) in your project.

    * Deployed a token server using either of the following guides:

      * [Deploy a token server](deploy-token-server.mdx)
      * [Deploy a middleware server](middleware-token-server.md)

    ## Implement basic authentication [#implement-basic-authentication-7]

    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 [#use-a-token-to-join-a-channel-7]

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

    1. Open the [SDK quickstart](../../index.mdx) project you created earlier.

    2. In `ProjectName.tsx` replace the contents with the following:

    **Sample code for basic authentication**

    ```js
      import React, { useCallback, useEffect, useRef, useState } from 'react';
        import {
          PermissionsAndroid,
          Platform,
          SafeAreaView,
          ScrollView,
          StyleSheet,
          Switch,
          Text,
          View,
        } from 'react-native';

        import {
          ChannelProfileType,
          ClientRoleType,
          createAgoraRtcEngine,
          IRtcEngine,
          IRtcEngineEventHandler,
          RtcConnection,
          RtcSurfaceView,
        } from 'react-native-agora';

        // Define basic information
        const appId = '<Your app ID>';
        const channelName = 'test';
        const uid = 123; // Local user Uid

        const App = () => {
        const agoraEngineRef = useRef<IRtcEngine>(); // IRtcEngine instance
        const eventHandlerRef = useRef<IRtcEngineEventHandler>(); // IRtcEngine event handler
        const [token, setToken] = useState<string>(''); // RTC Token
        const [isJoined, setIsJoined] = useState(false); // Whether the local user has joined the channel
        const [isHost, setIsHost] = useState(true); // User role
        const [remoteUid, setRemoteUid] = useState(0); // Uid of remote user
        const [message, setMessage] = useState(''); // Message to the user

        // Send a request to obtain a token to the token server
        const fetchToken = useCallback(() => {
          // Token server URL example: http://12.123.1.123:8082/fetch_rtc_token
          const url = '<Your host URL and port>/fetch_rtc_token';
          const body = JSON.stringify({
          uid,
          ChannelName: channelName,
          role: isHost
            ? ClientRoleType.ClientRoleBroadcaster
            : ClientRoleType.ClientRoleAudience,
          });
          console.log('fetchToken', url, body);
          return fetch(url, {
            method: 'POST',
            body,
          })
          .then((res) => res.json())
          .then((res) => {
            showMessage('token ' + res.token + 'Already refreshed');
            if (+res.code === 200) {
            setToken(res.token);
            }
            return res;
          });
          }, [isHost]);

        // Use the obtained token to join the channel
        const join = useCallback(async () => {
          if (!token) {
            await fetchToken();
          } else {
          try {
            // After joining the channel, set the channel profile to live broadcast
            agoraEngineRef.current?.setChannelProfile(
            ChannelProfileType.ChannelProfileLiveBroadcasting
            );
            if (isHost) {
            agoraEngineRef.current?.startPreview();
            // Join the channel as a host
            agoraEngineRef.current?.joinChannel(token, channelName, uid, {
              publishCameraTrack: true,
              clientRoleType: ClientRoleType.ClientRoleBroadcaster,
            });
            } else {
            // Join the channel as audience
            agoraEngineRef.current?.joinChannel(token, channelName, uid, {
              clientRoleType: ClientRoleType.ClientRoleAudience,
            });
            }
          } catch (e) {
            console.log(e);
          }
        }
        }, [fetchToken, isHost, token]);

        const leave = () => {
          try {
            agoraEngineRef.current?.leaveChannel();
            setRemoteUid(0);
            setIsJoined(false);
            showMessage('Left the channel');
          } catch (e) {
            console.error(e);
          }
        };

        useEffect(() => {
          const setupVideoSDKEngine = async () => {
          try {
            if (Platform.OS === 'android') {
            await getPermission();
            }
            agoraEngineRef.current = createAgoraRtcEngine();
            eventHandlerRef.current = {
            onJoinChannelSuccess: () => {
              showMessage('Successfully joined the channel: ' + channelName);
              setIsJoined(true);
            },
            onUserJoined: (_connection, Uid) => {
              showMessage('Remote user ' + Uid + ' joined');
              setRemoteUid(Uid);
            },
            onUserOffline: (_connection, Uid) => {
              showMessage('Remote user ' + Uid + ' left the channel');
              setRemoteUid(0);
            },
            onTokenPrivilegeWillExpire(connection: RtcConnection, token: string) {
              showMessage('token ' + token + 'Expires soon');
              fetchToken();
            },
            onRequestToken(connection: RtcConnection) {
              showMessage('token expired');
              setToken('');
            },
            };
            const agoraEngine = agoraEngineRef.current;
            //Initialize engine
            agoraEngine.initialize({
              appId: appId,
              channelProfile: ChannelProfileType.ChannelProfileLiveBroadcasting,
            });
            // Register event handler
            agoraEngine.registerEventHandler(eventHandlerRef.current);
            // Start local video
            agoraEngine.enableVideo();
          } catch (e) {
            console.error(e);
          }
        };

          setupVideoSDKEngine();

          return () => {
            agoraEngineRef.current?.release();
          };
        }, []); // eslint-disable-line react-hooks/exhaustive-deps

        useEffect(() => {
          const checkJoined = () => {
          if (isJoined) {
            console.log('renewToken');
            // agoraEngineRef.current?.renewToken(token);
          } else {
            console.log('joinChannel');
            join();
          }
          };
          checkJoined();
        }, [token]); // eslint-disable-line react-hooks/exhaustive-deps

        // Render the user interface
        return (
          <SafeAreaView style={styles.main}>
          <Text style={styles.head}>Agora SDK Quickstart</Text>
          <View style={styles.btnContainer}>
            <Text onPress={join} style={styles.button}>
            Join channel
            </Text>
            <Text onPress={leave} style={styles.button}>
            Leave Channel
            </Text>
          </View>
          <View style={styles.btnContainer}>
            <Text>Audience</Text>
            <Switch
            onValueChange={(switchValue) => {
              setIsHost(switchValue);
              if (isJoined) {
              leave();
              }
            }}
            value={isHost}
            />
            <Text>Host</Text>
          </View>
          <ScrollView
            style={styles.scroll}
            contentContainerStyle={styles.scrollContainer}
          >
            {isJoined ? (
            <React.Fragment key={0}>
              <RtcSurfaceView canvas={{ uid: 0 }} style={styles.videoView} />
              <Text>Local user uid: {uid}</Text>
            </React.Fragment>
            ) : (
            <Text>Join a channel</Text>
            )}
            {isJoined && !isHost && remoteUid !== 0 ? (
            <React.Fragment key={remoteUid}>
              <RtcSurfaceView
              canvas={{ uid: remoteUid }}
              style={styles.videoView}
              />
              <Text>Remote user uid: {remoteUid}</Text>
            </React.Fragment>
            ) : (
            <Text>{isJoined && !isHost ? 'Wait for a remote user to join' : ''}</Text>
            )}
            <Text style={styles.info}>{message}</Text>
          </ScrollView>
          </SafeAreaView>
        );

        // Show message
        function showMessage(msg: string) {
          console.info(msg);
          setMessage(msg);
        }
        };

        // Define user interface style
        const styles = StyleSheet.create({
          button: {
            paddingHorizontal: 25,
            paddingVertical: 4,
            fontWeight: 'bold',
            color: '#ffffff',
            backgroundColor: '#0055cc',
            margin: 5,
          },
          main: { flex: 1, alignItems: 'center' },
          scroll: { flex: 1, backgroundColor: '#ddeeff', width: '100%' },
          scrollContainer: { alignItems: 'center' },
          videoView: { width: '90%', height: 200 },
          btnContainer: { flexDirection: 'row', justifyContent: 'center' },
          head: { fontSize: 20 },
          info: { backgroundColor: '#ffffe0', paddingHorizontal: 8, color: '#0000ff' },
        });

        const getPermission = async () => {
          if (Platform.OS === 'android') {
            await PermissionsAndroid.requestMultiple([
            'android.permission.RECORD_AUDIO',
            'android.permission.CAMERA',
            ]);
          }
        };

        export default App;
    ```

    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.

    <CalloutContainer type="info">
      <CalloutDescription>
        The user ID and channel name used to join a channel must be consistent with the values used to generate the token.
      </CalloutDescription>
    </CalloutContainer>

    ## Reference [#reference-7]

    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 [#api-reference-6]

    * [renewToken](https://api-ref.agora.io/en/video-sdk/react-native/4.x/API/class_irtcengine.html#api_irtcengine_renewtoken)
    * [onTokenPrivilegeWillExpire](https://api-ref.agora.io/en/video-sdk/react-native/4.x/API/class_irtcengineeventhandler.html#callback_irtcengineeventhandler_ontokenprivilegewillexpire)
    * [onRequestToken](https://api-ref.agora.io/en/video-sdk/react-native/4.x/API/class_irtcengineeventhandler.html#callback_irtcengineeventhandler_onrequesttoken)