Application

Before you start building your chat, it is important to understand that your Sendbird application has core functionalities to maintain chat service stability and basic features for application management. This page presents how you can use a Sendbird application in your app to ensure optimal performance.

To prevent abnormal user activity, a Sendbird application has the following limits on the number of messages per second which a user can send and an open channel can display.

You can change the default limit settings by contacting our sales team.

Unlike the Chat SDKs for iOS and Android, the Chat SDK for JavaScript doesn't manage a connection to Sendbird server when the foreground and background states of your web app changes on a various types of devices. In that context, you should call the connect() or disconnect() methods explicitly depending on how you implement your use cases.

One user ID can make connections to up to 30 devices or browsers simultaneously. All connections from one user ID are counted and reflected in your application’s concurrent connections. Since they are used to calculate your service billing, caution is advised.

You can retrieve a list of all or certain users in your Sendbird application using an ApplicationUserListQuery instance. The next() method returns a list of User objects which contain information on users within the application.

// Retrieving all users
var sb = SendBird.getInstance();
var listQuery = sb.createApplicationUserListQuery();
listQuery.limit = 20;   // The value of pagination limit could be set up to 100.

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of users is successfully retrieved.
    // Through the "users" parameter of the callback function,
    // you can access the data of each user from the result list that Sendbird server has passed to the callback function.
    ...
});

With the several different types of filters the ApplicationUserListQuery instance provides, you can retrieve a list of specific users that match the set values in the filters. Currently the ApplicationUserListQuery instance supports the following three filters:

Note: We recommend you set the maximum number of user IDs to 250 in the UserID filter. If exceeded, your query may receive an HTTP 414 error indicating that the submitted request data is longer than Sendbird server is willing to interpret.

// Retrieving certain users using the UserID filter
var listQuery = sb.createApplicationUserListQuery();
listQuery.userIdsFilter = ['Harry', 'Jay', 'Jin'];

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of matching users is successfully retrieved.
    ...
});

// Retrieving certain users using the MetaDataKey and MetaDataValue filter
var listQuery = sb.createApplicationUserListQuery();
listQuery.metaDataKeyFilter = 'hobby';
listQuery.metaDataValuesFilter = ['movie', 'book', 'exercise'];

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of matching users is successfully retrieved.
    ...
});

// Retrieving certain users using the NicknameStartsWith filter
var listQuery = sb.createApplicationUserListQuery();
listQuery.nicknameStartsWithFilter = 'Ja';

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of matching users is successfully retrieved.
    ...
});

A user can block specific users to stop receiving further messages from them in 1-to-1 group channels and notifications of their messages in 1-to-N group channels. You can choose whether or not users can view which users they have blocked in the channel UI.

A Sendbird application provides two blocking options: including or excluding blocked users when sending invitations and turning on/off push notifications from blocked users. The previous block modes are now deprecated and only supported for customers who have been using them from before.

• Including or excluding blocked users when sending invitations: determines whether or not to automatically filter out blocked users when a user invites a group of users to a new group channel. The value of this option can be adjusted only from our side before integrating your Sendbird application to an app. If you want to change the value, contact our sales team for further assistance. (Default: including)
• Turning on/off push notifications from blocked users: determines whether or not to send push notifications to a user for the messages that blocked users sent in a specific 1-to-N group channel where they are members together. The value of this option can be set individually by channel. If you want to use this option, contact our sales team for further assistance. (Default: off)

You can allow a users to block and unblock other users by implementing the following code to your client app.

// Blocking a user
var sb = SendBird.getInstance();
sb.blockUser(USER, function(user, error) {
    if (error) {
        // Handle error.
    }

    // The blocked user can be retrieved through the "user" parameter of the callback function.
    ...
});

Note: You can use the blockUserWithUserId() and unblockUserWithUserId() methods, instead of the blockUser() and unblockUser() methods, as they have same functionalities. Please see our API reference for more information on the blockUserWithUserId() and unblockUserWithUserID().

You can retrieve a list of all or certain blocked users in your Sendbird application using a BlockedUserListQuery instance. The next() method returns a list of User objects which contain information on blocked users.

// Retrieving all blocked users.
var sb = SendBird.getInstance();
var listQuery = sb.createBlockedUserListQuery();

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of blocked users is successfully retrieved.
    // Through the "users" parameter of the callback function,
    // you can access the data of each blocked user from the result list that Sendbird server has passed to the callback function.
    ...
});

With the BlockedUserListQuery's UserID filter, you can retrieve a list of the blocked users that match the user IDs in the filter.

// Retrieving certain blocked users using the UserID filter.
var listQuery = sb.createBlockedUserListQuery();
listQuery.userIdsFilter = ['John', 'Daniel', 'Jeff'];

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // A list of matching users is successfully retrieved.
    ...
});

You can check if a certain user is currently connected to Sendbird server.

var sb = SendBird.getInstance();
var listQuery = sb.createApplicationUserListQuery();
listQuery.userIdsFilter = ['Jeff'];

listQuery.next(function(users, error) {
    if (error) {
        // Handle error.
    }

    // users[0] = 'Jeff'
    if (users[0].connectionStatus === sb.User.ONLINE) {
        // 'Jeff' is currently online.
        // User.connectionStatus consists of NON_AVAILABLE, ONLINE, and OFFLINE.
        ...
    }
});