In order to use the features of the Chat SDK in your client apps, a
SendbirdChat instance must be initiated in each client app through user authentication with Sendbird server. The instance communicates and interacts with the server using an 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 a
SendbirdChat instance by passing the
APP_ID of your Sendbird application as an argument to a parameter of the
initialize(params:) method. The
initialize(params:) must be called once across your client app. Generally, initialization is implemented in the user login view controller.
With local caching, two new parameters have been added to the initialization code, which are
useCaching determines whether the client app will use the local storage through Sendbird Chat SDK or not. If you want to build a client app with our local caching functionalities, set the
useCaching to true.
completionHandler: gets the initialization status through different event handlers. For Objective-C, the
migrationStartHandler: is called when there's a change in the local cache. Meanwhile, the
completionHandler: informs the client app whether the initialization is successful or not.
If the initialization fails when you set the
useCaching to true, the SDK will operate normally and change the value of the
useCaching to false. If you still wish to use the local caching, clear the database using the
clearCachedDataWithCompletionHandler: and try the initialization again with the
useCaching set to true.
By default, Sendbird server can authenticate a user just by a unique user ID. Then the server queries the database to check for a match upon the request for connection. If no matching user ID is found, the server creates a new user account with the user ID. The ID must be unique within a Sendbird application to be distinguished from others, such as a hashed email address or phone number in your service.
This authentication procedure is useful when in development or if your service doesn't require additional security.
Note: Go to the Event delegate page to learn more about the usages of the Chat SDK's delegates and callbacks.
Note: You must connect to Sendbird server before calling any methods through the Chat SDK, except when initializing a
SendbirdChatinstance. If you attempt to call a method without connecting, a
.connectionRequired (800101)error will be returned.
When a user logs in to a client app using the Chat SDK, you can choose how to authenticate a user. A user authentication can be done with just their own user ID, but also with either an access token or a session token. If any token is issued for a user, it must be provided to Sendbird server each time the user logs in by using the
Using the Chat API, create a Sendbird user account with the information submitted when a user signs up or 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 the application, 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 in your dashboard, you are 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. It's a more secure option because session tokens expire after a certain period whereas access tokens don't. Our Chat Platform API guide further explains 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 logs in to a client app using the Chat SDK, a user can be authenticated with a session token. If a user is authenticated with a session token, the Chat SDK connects the user to Sendbird server and can send data requests to it 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. 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
SessionDelegate to refresh the token and pass it back to the SDK so that it can refresh the session again.
SessionDelegatemust be set before the server connection is requested.
The following code shows how to implement the handler.
A user should be disconnected from 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 the
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.
updateCurrentUserInfo(params:completionHandler:), you can update a user's nickname and profile image with a URL.
Or, you can directly upload a profile image like the following:
Note: A user's profile image can be a
PNG(.png) file of up to 25 MB.