Group channel: Advanced

This page explains the advanced features for group channels.

If the startTyping and endTyping methods are called while the current user is typing a message in a group channel, the channelDidUpdateTypingStatus: in the channel delegate will be invoked on all channel members' devices except the one that belongs to the current user.

[groupChannel startTyping];
[groupChannel endTyping];


// To listen to an update from all the other channel members' client apps, implement the channelDidUpdateTypingStatus: with things to do when notified.
@interface GroupChannelChattingViewController : UIViewController<SBDChannelDelegate>

@end

@implementation GroupChannelChattingViewController

- (void)initGroupChannelChattingViewController {
    [SBDMain addChannelDelegate:self identifier:UNIQUE_DELEGATE_ID];
}

- (void)channelDidUpdateTypingStatus:(SBDGroupChannel * _Nonnull)sender {
    if ([sender.channelUrl isEqualToString:groupChannel.channelUrl]) {
        NSArray<SBDUser *> *members = [sender getTypingMembers];

        // Refresh typing status of members within the channel.
    }
}

@end

To mark messages as delivered when a group channel member successfully receives a push notification for the message from APNs, the markAsDeliveredWithRemoteNotificationPayload:completionHandler: method should be implemented in Notification Service Extension.

import SendBirdSDK

class NotificationService: UNNotificationServiceExtension {

    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        if let bestAttemptContent = bestAttemptContent {
            // Modify the notification content here
            bestAttemptContent.title = "\(bestAttemptContent.title) [modified]"


            SBDMain.setAppGroup("APP_GROUP")
            SBDMain.markAsDelivered(withRemoteNotificationPayload: bestAttemptContent.userInfo) { (error) in
                guard error == nil else {
                    // Handle error.
                }


            }


            contentHandler(bestAttemptContent)
        }
    }

}

When a message is delivered to an online group channel member, it is automatically marked as delivered and the other online members are notified of delivery receipt through the channelDidUpdateDeliveryReceipt: method of SBDChannelDelegate. However, when it is delivered to an offline member as a push notification, the message can be marked as delivered through the markAsDeliveredWithRemoteNotificiationPayload method of SBDMain, and other online members are notified of the delivery receipt through the channelDidUpdateDeliveryReceipt: method.

class GroupChannelChattingViewController: UIViewController, SBDChannelDelegate {
    SBDMain.add(self as SBDChannelDelegate, identifier: UNIQUE_DELEGATE_ID)

    func channelDidUpdateDeliveryReceipt(_ sender: SBDGroupChannel) {
        ...
    }
}

To keep the most up-to-date and accurate read status of messages for all group channel members, the markAsRead() method should be called every time one of the members reads messages by entering the channel from a channel list or bringing the opened channel view to the foreground.

If the current user opens a channel and the markAsReadAll() is called, Sendbird server will update both the unread message count of the individual channel and the total unread message count of all the group channels joined by the user. Then the server triggers the channelDidUpdateReadReceipt: method of the channel event delegate to notify the change of read status to all channel members' devices, except the one that is being used by the current user.

Note : When a channel member sends a message to the channel, Sendbird server updates the member's read receipt to the time when the message has sent. Meanwhile, the read receipts of other channel members can be updated when the markAsRead() method is called. If a new member joins the channel, the method works differently based on the value of the display_past_message property of your Sendbird application. If the property is set to YES, the new member’s read receipt will be updated to the sent time of the last message in the channel. If NO, it will be updated to 0.

// Call the markAsRead when the current user views unread messages in a group channel.
groupChannel?.markAsRead()
...

// To listen to an update from all the other channel members' client apps, implement the channelDidUpdateReadReceipt() with things to do when notified.
class GroupChannelChattingViewController: UIViewController, SBDChannelDelegate {
    SBDMain.add(self as SBDChannelDelegate, identifier: UNIQUE_DELEGATE_ID)

    func channelDidUpdateReadReceipt(_ sender: SBDGroupChannel) {
        if currentGroupChannel?.channelUrl == sender.channelUrl {
            // For example, code for redrawing a channel view.
        }
    }
}

Note: The display_past_message property determines whether to display past messages to newly joined members when they enter the channel. This property is also linked to the Chat history option, which can be adjusted in your dashboard under Settings > Chat > Channels > Group channels.

You can retrieve the number of members who haven’t received a specific message in a group channel. If zero is returned, it means that the message has been delivered to all the other members.

let count = channel?.getUndeliveredMemberCount(message)

Using the getReadMembersWithMessage: method, you can view members who have read a specific message in a group channel. The method returns a list of channel members who have read the message by comparing the message’s creation time and the channel members’ read receipt. The list will exclude the current user and the message sender.

Note: Read receipt indicates the timestamp of the latest time when each user has read messages in the channel, in Unix milliseconds.

If you want to keep track of who has read a new message, we recommend to use the getReadMembersWithMessage: in the channelDidUpdateReadReceipt: of the channel event delegate. Then the client app will receive a callback from Sendbird server whenever a channel member reads a message. To do so, you should pass the new message object as an argument to a parameter in the getReadMembersWithMessage: through the channelDidUpdateReadReceipt.

let readMembers = groupChannel.getReadMembers(with: baseMessage)

Note: Using the getUnreadMembersWithMessage: method, you can also view members who have not read a specific message in a group channel, except the current user and the message sender. In the meantime, you can get information on each channel member's read receipt through the getReadStatus method.

Using the getReadReceiptOfMessage: method, you can get the number of members who have not read a specific message in a group channel. To get the exact value, the channel should be updated first through the markAsRead before calling the getReadReceiptOfMessage:.

// Call the 'markAsRead' when the current user views unread messages in a group channel.
groupChannel?.markAsRead()
...

// To listen to an update from all the other channel members' client apps, implement the channelDidUpdateReadReceipt() with things to do when notified.
class GroupChannelChattingViewController: UIViewController, SBDChannelDelegate {
    SBDMain.add(self as SBDChannelDelegate, identifier: UNIQUE_DELEGATE_ID)

    func channelDidUpdateReadReceipt(_ sender: SBDGroupChannel) {
        if currentGroupChannel?.channelUrl == sender.channelUrl {
            ...

            for msg in messages {
                let unreadCount = sender.getReadReceipt(of: msg)
                if unreadCount <= 0 {
                    // All members have read the message.
                }
                else {
                    // Some of members haven't read the message.
                }
            }
        }
    }
}

You can retrieve the last message of a group channel.

let lastMessage = groupChannel.lastMessage

You can retrieve the total number of the current user's unread messages in a group channel.

let unreadMessageCount = groupChannel.unreadMessageCount

You can retrieve the total number of the current user's unread messages in all joined group channels.

SBDMain.getTotalUnreadMessageCount(completionHandler: { (unreadCount, error) in
    guard error == nil else {
        // Handle error.
    }

    ...
})

You can retrieve the total number of the current user's joined group channels which one or more unread messages.

SBDMain.getTotalUnreadChannelCount(completionHandler: { (unreadCount, error) in
    guard error == nil else {
        // Handle error.
    }

    ...
})

You can send admin messages to a group channel using Sendbird Dashboard or Chat Platform API. To send an admin message through your dashboard, go to the Chat > Group channels, select a group channel, find the message box below, click the Admin message tab, and then write your message in the box. An admin message is limited to 1,000 characters.

Unlike other types of messages, a push notification for an admin message is not available by default. If you want assistance on this, contact our sales team.

You have the option to create further actions in a channel by using extra data in a message. You can add one or more key-values items to a message which you can save, update, or remove, when necessary. Based on those items, you can design and implement several different actions such as measuring user engagement within a chosen time limit through polls or counting how many times a message has been copied by members.

Note: For the quality of performance, every Sendbird application has its own limits to how many key-values items you can add to a single message, as well as the maximum number of values an item can have. If you would like more information on these limits, contact our sales team.

// When a message has been successfully sent to a channel, creating items with keys.
groupChannel.createMessageMetaArrayKeys(with: MESSAGE, keys: ["referees", "games"], completionHandler: { (message, error) in
    guard error == nil else {
        // Handle error.
    }


})

// Adding values to specific items by their keys.
let valuesToAdd = [
    "referees": ["John", "Brandon", "Harry", "Jay"],
    "games": ["soccer", "baseball", "basketball"]
]

groupChannel.addMessageMetaArrayValues(with: MESSAGE, keyValues: valuesToAdd, completionHandler: { (message, error) in
    guard error == nil else {
        // Handle error.
    }


})

// Removing existing values of specific items by their keys.
let valuesToRemove = [
    "referees": ["Brandon", "Jay"]
]

groupChannel.removeMessageMetaArrayValues(with: MESSAGE, keyValues: valuesToRemove, completionHandler: { (message, error) in
    guard error == nil else {
        // Handle error.
    }


})

// Deleting items by their keys.
groupChannel.deleteMessageMetaArrayKeys(with: MESSAGE, keys: ["referees", "games"], completionHandler: { (message, error) in
    guard error == nil else {
        // Handle error.
    }


})

To get the key-values items of a message, read the message.metaArrays.

The Chat SDK supports the URL link preview when a message text contains the URL of a web page.

Note: This feature is turned on by default for Sendbird applications. If this isn't available for your Sendbird application, contact our support team to enable the feature.

To view the image in full screen, click on the

If a SBDBaseMessage object includes a valid URL of a website, the object can contain SBDOGMetaData, a class that holds the OG metadata such as title, URL, description, and default image of an OG object.

Note: Some websites don’t provide the OG metadata. In that case, even though the Open Graph protocol states them as requirements, all of the four properties can be null.

A SBDOGImage, the image contained in a SBDOGMetaData object, is a class that holds image-related data for the SBDOGImage object. The SBDOGImage class can also have its own optional structured properties of URL, secure URL, type, width, height, and alt.

Note: Except for width and height, other fields such as URL, secure URL, type, and alt can be null. If the target website doesn’t provide width and height data, the value of those two fields are set to 0.

If a user sends a message with a web page URL and the linked web page possesses Open Graph (OG) tags, or OG metadata, Sendbird server parses the message content, extracts the URL in the message, gets the OG metadata from it, and creates an OG metadata object for the message. Then message recipients will get the parsed message with its OG metadata through the didReceiveMessage: method in the channel event delegate of the SDK. On the other hand, the message sender will do the same through the didUpdateMessage:.

Displaying an OG metadata object is available for two subtypes of a SBDBaseMessage: SBDUserMessage and SBDAdminMessage. If the content of either a SBDUserMessage or SBDAdminMessage object includes a web page URL containing OG metadata, the didReceiveMessage: method returns SBDOGMetaData and SBDOGImage objects.

If Sendbird server doesn’t have cache memory of the OG metadata of the given URL, the SBDBaseMessage.ogMetaData can be null due to the time it takes to fetch the OG metadata from a remote web page. In the meantime, the message text containing the URL will be delivered first to message recipients’ client app through the didReceiveMessage: method. When the server completes fetching, the didUpdateMessage: method will be called and the message with its SBDOGMetaData object will be delivered to the recipients’ client app. However, if Sendbird server has already cached the OG metadata of the URL, the SBDBaseMessage.ogMetaData returns the message and its SBDOGMetaData object instantly and the didUpdateMessage: method won’t be called.

// Send a user message containing the URL of a web page.
var params = SBDUserMessageParams()
params.message = "sendbird.com"
...

groupChannel.sendUserMessage(with: params, completionHandler: { (userMessage, error) in
    guard error == nil else {
        // Handle error.
    }

    ...
})

// ViewController.swift
// Receive a user message containing OG metadata of the web page through a channel event delegate.
func channel(_ sender: SBDBaseChannel, didReceive message: SBDBaseMessage) {
    if message.ogMetaData != nil {
        // You can create and customize the URL link preview by using the Open Graph metadata of the message.
        let url = message.ogMetaData.url
        let width = message.ogMetaData.width


    } else {
        // If the message.ogMetaData is nil, wait until the channel:didUpdate method receives a callback from Sendbird server.
    }


}

func channel(_ sender: SBDBaseChannel, didUpdate message: SBDBaseMessage) {
    if message.ogMetaData != nil {
        // You can create and customize the URL link preview by using the Open Graph metadata of the message.
        let url = message.ogMetaData.url
        let width = message.ogMetaData.width


    }


}

When creating a group channel, you can additionally specify a custom channel type to subclassify group channels. This custom type takes on the form of a NSString, and can be useful in searching or filtering group channels.

The data and customType properties of a channel object allow you to append information to your channels. While both properties can be used flexibly, common examples for the customType include categorizing group channels into School or Work.

var users: [String] = []
users.append("Jed")
users.append("Young")

var params = SBDGroupChannelParams()
params.addUserIds(users)
params.name = NAME
params.customType = CUSTOM_TYPE


SBDGroupChannel.createChannel(with: params, completionHandler: { (channel, error) in
    guard error == nil else {
        // Handle error.
    }


})

To get a channel's custom type, read the groupChannel.customType.

When sending a message, you can additionally specify a custom message type to subclassify messages. This custom type takes on the form of a NSString, and can be useful in searching or filtering messages.

The data and customType properties of a message object allow you to append information to your messages. While both properties can be used flexibly, common examples for the customType include categorizing message groups into Notes or Contacts.

To embed a custom type into your message, assign a value to the customType under the SBDUserMessageParams or SBDFileMessageParams object. Then, pass the specified object as an argument to the parameter in the sendUserMessageWithParams:completionHandler: or sendFileMessageWithParams:completionHandler: method.

var params = SBDUserMessageParams()
params.message = MESSAGE
params.customType = CUSTOM_TYPE
...

groupChannel.sendUserMessage(with: params, completionHandler: { (userMessage, error) i
    guard error == nil else {
        // Handle error.
    }

    ...
})

To get a message's custom type, read the message.customType.

You can search for specific group channels by using several types of search filters within the SBDGroupChannelListQuery and SBDPublicGroupChannelListQuery classes.

A SBDGroupChannelListQuery instance provides many types of search filters such as channelNameContainsFilter and channelUrlsFilter. You can use these filters to search for specific private group channels.

The sample code below shows the query instance, which returns a list of the current user's group channels that partially match the specified keyword in the channelNameContainsFilter in the channels' name.

let listQuery = SBDGroupChannel.createMyGroupChannelListQuery()
listQuery.includeEmptyChannel = true
listQuery.setSearchFilter(with: "Sendbird", fields: .channelName)

listQuery.loadNextPage(completionHandler: { (groupChannels, error) in
    guard error == nil else {
        // Handle error.
    }

    // Through "groupChannels" parameter of the callback method, which Sendbird server has passed a result list to,
    // a list of group channels that partially match 'Sendbird' in their names is returned.

})

The following shows the query instance, which returns a list of the current user's group channels that partially match the specified keyword in the channelUrlsFilter in the channels' URL.

let listQuery = SBDGroupChannel.createMyGroupChannelListQuery()
listQuery.includeEmptyChannel = true

var channelUrls: [String] = []
channelUrls.append("seminar")
channelUrls.append("lecture")

listQuery.channelUrlsFilter = channelUrls

listQuery.loadNextPage(completionHandler: { (groupChannels, error) in
    guard error == nil else {
        // Handle error.
    }

    // Through "groupChannels" parameter of the callback method, which Sendbird server has passed a result list to,
    // a list of group channels that partially match 'seminar' or 'lecture' in their names is returned.

})

The following table shows all supported filters for SBDGroupChannelListQuery to search for specific channels you want to retrieve. You can use any filters in a similar fashion with the sample code above.

A SBDPublicGroupChannelListQuery instance provides many types of search filters such as channelNameContainsFilter and channelUrlsFilter. You can use these filters to search for specific public group channels.

The sample code below shows the query instance, which returns a list of the current user's group channels that partially match the specified keyword in the channelNameContainsFilter in the channels' name.

let listQuery = SBDGroupChannel.createPublicGroupChannelListQuery()
listQuery.includeEmptyChannel = true
listQuery.setSearchFilter(with: "Sendbird", fields: .channelName)

listQuery.loadNextPage(completionHandler: { (groupChannels, error) in
    guard error == nil else {
        // Handle error.
    }

    // Through "groupChannels" parameter of the callback method, which Sendbird server has passed a result list to,
    // a list of group channels that partially match 'Sendbird' in their names is returned.

})

The following shows the query instance, which returns a list of the current user's group channels that partially match the specified keyword in the channelUrlsFilter in the channels' URL.

let listQuery = SBDGroupChannel.createPublicGroupChannelListQuery()
listQuery.includeEmptyChannel = true

var channelUrls: [String] = []
channelUrls.append("seminar")
channelUrls.append("lecture")

listQuery.channelUrlsFilter = channelUrls

listQuery.loadNextPage(completionHandler: { (groupChannels, error) in
    guard error == nil else {
        // Handle error.
    }

    // Through "groupChannels" parameter of the callback method, which Sendbird server has passed a result list to,
    // a list of group channels that partially match 'seminar' or 'lecture' in their names is returned.

})

The following table shows all supported filters for SBDPublicGroupChannelListQuery to search for specific channels you want to retrieve. You can use any filters in a similar fashion with the sample code above.

SBDMessageSearchQuery.create()

SBDMessageSearchQuery.create { (builder) in
    builder.keyword = "Sendbird"
    builder.limit = 10


}

query.loadNextPage { (messages, error) in
    guard error == nil else {
        // Handle error.
    }

    ...
}

(BOOL)hasNext;

(BOOL)isLoading;

var thumbnailSizes = [SBDThumbnailSize]()

// Creating and adding a SBDThumbnailSize object (allowed number of thumbnail images: 3).
thumbnailSizes.append(SBDThumbnailSize.make(withMaxCGSize: CGSize(width: 100.0, height: 100.0))!)
thumbnailSizes.append(SBDThumbnailSize.make(withMaxWidth: 200.0, maxHeight: 200.0)!)

var params = SBDFileMessageParams()

params.file = FILE
params.fileName = FILE_NAME
params.fileSize = FILE_SIZE
params.mimeType = MIME_TYPE
params.thumbnailSizes = thumbnailSizes  // Set a SBDThumbnailSize object to a SBDFileMessageParams object.

groupChannel.sendFileMessage(with: params, completionHandler: { (fileMessage, error) in
    guard error == nil else {
        // Handle error.
    }

    let first = fileMessage?.thumbnails?[0]
    let second = fileMessage?.thumbnails?[1]

    let maxSizeFirst = first?.maxSize      // 100
    let maxSizeSecond = second?.maxSize  // 200

    let urlFirst = first?.url
    let urlSecond = second?.url


}

SBDFileMessageParams *params = [[SBDFileMessageParams alloc] init];

[params setFileName:FILE_NAME];
[params setData:FILE_DATA];
[params setCustomType:CUSTOM_TYPE];

SBDFileMessage *fileMessage = [groupChannel sendFileMessageWithParams:params progressHandler:^(int64_t bytesSent, int64_t totalBytesSent, int64_t totalBytesExpectedToSend) {
    CGFloat progress = totalBytesSent / totalBytesExpectedToSend;

} completionHandler:^(SBDFileMessage * _Nonnull fileMessage, SBDError * _Nullable error) {
    if (error != nil) {
        // Handle error.
    }

    // Do something with the sent file message.

}];

let fileMessage = channel.sendFileMessage(
    with: params,
    progressHandler: { bytesSent, totalBytesSent, totalBytesExpectedToSend in
        ...
    },
    completionHandler: { message, error in
        ...
    }
)

// Cancel uploading a file in the file message.
SBDGroupChannel.cancelUploadingFileMessage(withRequestId: fileMessage.requestId(), completionHandler: { (result, error) in
    ...
})

var params = SBDUserMessageParams()
...
params.targetLanguages = ["es", "ko"]   // Spanish and Korean

groupChannel.sendUserMessage(with: params, completionHandler: { (userMessage, error) in
    guard error == nil else {
        // Handle error.
    }

    ...
})

func channel(_ sender: SBDBaseChannel, didReceive message: SBDBaseMessage) {
    If let message = message as? SBDUserMessage {
        let esTranslatedMessage = message.translations["es"]    // Spanish


        // Display translation in UI.
    }
}

let targetLanguages = ["es", "de"]

// The USER_MESSAGE below indicates a SBDUserMessage object which represents an already sent or received text message.
groupChannel.translateUserMessage(USER_MESSAGE, targetLanguages: targetLanguages, completionHandler: { (userMessage, error) in
    guard error == nil else {
        // Handle error.
    }

    let translations = (userMessage as! SBDUserMessage).translations
    let esTranslatedMessage = translations["es"]
    let deTranslatedMessage = translations["de"]
    ...

    // Display translations in UI.
})