SendbirdChat instance should be initiated in each client app through user authentication with the Sendbird server. The instance communicates and interacts with the server based on the authenticated user account and is allowed to use the Chat SDK's features. This page explains how to authenticate your user with the server.
To use our chat features, you must initialize the
SendbirdChat instance by passing
APP_ID of your Sendbird application as an argument to a parameter of the
initialize(params:migrationStartHandler:completionHandler:) method. The
initialize(params:migrationStartHandler:completionHandler:) method must be called once across your client app. Typically, initialization is implemented in the user login view.
With the implementation of local caching, the
isLocalCachingEnabled property of the
InitParams object has been added. Additionally, two callback functions,
completionHandler, have also been added to the initialization code as shown below.
isLocalCachingEnabled parameter determines whether or not the client app will use local storage through Sendbird Chat SDK. Since this is optional, the default value is set to
false. If you want to build a client app with our local caching functionalities, set the
isLocalCachingEnabled parameter to
completionHandler gets the initialization status through different event handlers and informs the client app whether the initialization is successful or not. On the other hand, the
migrationStartHandler is called when the migration for local caching has started.
If the initialization fails when you set
true, the SDK will operate normally and change the value of the
false. If you still wish to use local caching, clear the database using the
clearCachedData(completionHandler:) and try the initialization again with
isLocalCachingEnabled set to
By default, the Sendbird server can authenticate a user with just a unique user ID. Then, the server queries the database to check for a match upon connection request. If no matching user ID is found, the server creates a new user account with the user ID. The ID should be unique within a Sendbird application to be distinguishable from other identifiers such as a hashed email address or a phone number in your service.
While authenticating with just the user ID is convenient in the developing and testing stages of a service, a more secure authentication process using tokens is strongly recommended for most production environments.
Note: Go to the event delegate page to learn more about the usages of the Chat SDK's delegates and callbacks.
Note: Apart from initializing the
SendbirdChatinstance, you should connect to the Sendbird server before calling almost every method through the Chat SDK. If you attempt to call a method without connecting, a
.connectionRequired (800101)error will be returned.
For a more secure way of authenticating a user, you can require an authentication token, which can be an access token or a session token, in addition to a unique user ID. Any token issued for a user must be provided to the Sendbird server each time the user logs in by passing the token as an argument to the
authToken parameter of the
Through our Chat Platform API, an access token can be generated when creating a user. You can also issue an access token for an existing user. Once an access token is issued, a user is required to provide the access token in the
connect() method which is used for logging in.
Using the Chat API, create a Sendbird user account with information submitted when a user signs up or logs in to your service.
Save the user ID along with the issued access token to your persistent storage which is securely managed.
When the user attempts to log in to a client app, load the user ID and access token from the storage, and then pass them to the
Periodically replacing the user's access token is recommended to protect the account.
Note: From Settings > Application > Security > Access token permission setting on your dashboard, you're able to prevent users without an access token from logging in to your Sendbird application or restrict their access to read and write messages.
You can also use a session token instead of an access token to authenticate a user. Session tokens are a more secure option because they expire after a certain period whereas access tokens don't. See Chat Platform API guides for further explanation about the difference between access token and session token, how to issue a session token, and how to revoke all session tokens.
When a user is authenticated with a session token, the Chat SDK connects the user to the Sendbird server and can send data requests to the server for ten minutes as long as the session token hasn't expired or hasn't been revoked.
Upon the user's session expiration, the Chat SDK will refresh the session internally using a
SessionDelegate. However, if the session token has expired or has been revoked, the Chat SDK can't do so. In that case, the client app needs to implement a
SessionDelegate instance to refresh the token and pass it back to the SDK so that it can refresh the session again.
SessionDelegateinstance must be set before the server connection is requested.
The following code shows how to implement the delegate methods.
A user can be disconnected from the Sendbird server when they no longer need to receive messages from an online state. However, the user will still receive push notifications for new messages from group channels they've joined.
When disconnected, all event delegates in a user's client app registered by
add(_:identifier:) stop receiving event callbacks from the server. Then, all internally cached data in the client app, such as the channels that are cached when the
getChannel(url:completionHandler:) method of
GroupChannel is called, are also flushed.
Note: By default, most of the data related to users, channels, and messages are internally cached in the
SendbirdChatinstance of a user's client app, which are retrieved by the corresponding query instances or received through the event delegates.