Group channel: Advanced
This page explains the advanced features for group channels.
Send typing indicators to other members
If the startTyping()
and endTyping()
methods are called while the current user is typing a text message in a group channel, the onTypingStatusUpdated()
in the channel event handler will be invoked on all channel members' devices except the one that belongs to the current user.
Mark messages as delivered
To mark messages as delivered when a group channel member receives a push notification for the message from FCM, call the SendBird.markAsDelivered(Map<String, String>)
static method.
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 onDeliveryReceiptUpdated()
method in the channel event handler. However, when it is delivered to an offline group channel member as a push notification, the message can be marked as delivered through the groupChannel.markAsDelivered()
, and other online members are notified of the delivery receipt through the onDeliveryReceiptUpdated()
.
Mark messages as read
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. The server then notifies the change of read status to all members' devices through the onReadReceiptUpdated()
method in the channel event handler, 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 thedisplay_past_message
property of your Sendbird application. If the property is set to true, the new member’s read receipt will be updated to the sent time of the last message in the channel. If false, it will be updated to 0.
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 theChat history
option, which can be adjusted in your dashboard under Settings > Chat > Channels > Group channels.
Retrieve number of members who haven't received a message
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.
Retrieve members who have read a message
Using the getReadMembers()
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 that you use the getReadMembers()
in the onReadReceiptUpdated()
. 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 getReadMembers()
through the onReadReceiptUpdated()
.
Note: Using the
getUnreadMembers()
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 thegetReadStatus()
method.
Retrieve number of members who haven't read a message
Using the getReadReceipt()
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 getReadReceipt()
.
Retrieve the last message of a channel
You can view the last message of a group channel.
Retrieve number of unread messages in a channel
You can retrieve the total number of the current user's unread messages in a group channel.
Retrieve number of unread messages in all channels
You can retrieve the total number of the current user's unread messages in all joined group channels.
Retrieve number of channels with unread messages
You can retrieve the total number of the current user's joined group channels with one or more unread messages.
Send an admin message
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.
Add extra data to a message
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.
To get the key-values items of a message, use the message.getAllMetaArrays()
method.
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.
OGMetaData
is a class that holds the Open Graph (OG) protocol-related data, including the four properties: title, URL, description, and image of an OG object.
Note: Some websites don’t provide the OG metadata fields mentioned above. In that case, even though the Open Graph protocol states them as requirements, all of the four getter methods may return null.
List of methods
Method | Description |
---|---|
getTitle() | Returns the title of the OG object as it should appear within the graph. The value can be null. |
getUrl() | Returns the canonical URL of the object that can be used as its permanent ID in the graph. The value can be null. |
getDescription() | Returns the description of the object. The value can be null. |
getOGImage() | Returns an |
OGImage
is a class that holds image-related data for an OGMetaData
object. The OGImage
class can also have six 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. Width and height are set to 0 if the target website doesn’t provide such data.
List of methods
Method | Description |
---|---|
getUrl() | Returns the URL of an image object within the Open Graph. The value can be null. |
getSecureUrl() | Returns an alternative url to use if the webpage requires |
getType() | Returns a media type or MIME type of this image. The value can be null. |
getWidth() | Returns the number of pixels horizontal. When the value is unavailable, this method returns 0. |
getHeight() | Returns the number of pixels vertical. When the value is unavailable, this method returns 0. |
getAlt() | Returns a description of what is in the image, not a caption of the image. The alt attribute is designed to provide a fuller context of the |
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 object through the onMessageReceived()
method in the channel event handler of the SDK. On the other hand, the message sender will do the same through the onMessageUpdated()
.
Displaying an OG metadata object is available for two subtypes of BaseMessage
: UserMessage
and AdminMessage
. If the content of a BaseMessage
object includes a web page URL containing OG metadata, the BaseMessage.getOgMetaData()
method returns OGMetaData
and OGImage
objects.
If Sendbird server doesn’t have cache memory of the OG metadata of the given URL, the BaseMessage.getOgMetaData()
method can return null due to the time it takes to fetch the OG metadata from the corresponding remote web page. In the meantime, the message text containing the URL will be delivered first to message recipients’ client app through the onMessageReceived()
method. When the server completes fetching, the onMessageUpdated()
method will be called and the message with its OG metadata object will be delivered to the recipients’ client app. However, if Sendbird server has already cached the OG metadata of the URL, the BaseMessage.getOgMetaData()
method returns the message and its OGMetaData
object instantly and the onMessageUpdated()
method won’t be called.
Categorize channels by custom type
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 String
, 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 channels into School or Work.
To get a channel's custom type, use the groupChannel.getCustomType()
method.
Categorize messages by custom type
When sending a message, you can additionally specify a custom message type to subclassify messages. This custom type takes on the form of a String
, 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 UserMessageParams
or FileMessageParams
object. Then, pass the specified object as an argument to the parameter in the sendUserMessage()
or sendFileMessage()
method.
To get a message's custom type, use the message.getCustomType()
method.
Search channels by name, URL, or other filters
You can search for specific group channels by using several types of search filters within GroupChannelListQuery
and PublicGroupChannelListQuery
classes.
GroupChannelListQuery
A GroupChannelListQuery
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.
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.
The following table shows all supported filters for GroupChannelListQuery
to search for specific channels you want to retrieve. You can use any filters in a similar fashion with the sample code above.
List of filters
Name | Filters... |
---|---|
CustomTypesFilter | Group channels with one or more specified custom types. You can enable this filter using the |
CustomTypeStartsWithFilter | Group channels with a custom type that starts with the specified value. You can enable this filter using the |
ChannelNameContainsFilter | Group channels that contain the specified value in their names. You can enable this filter using the |
ChannelUrlsFilter | Group channels with one or more specified channel URLs. You can enable this filter using the |
SuperChannelFilter | Either super or nonsuper group channels. Using the |
PublicChannelFilter | Either public or private group channels. Using the |
UnreadChannelFilter | Group channels with one or more unread messages. Using the |
HiddenChannelFilter | Group channels with the specified state and operating behavior. You can enable this filter using the |
MemberStateFilter | Group channels based on whether the user has accepted an invitation. You can enable this filter using the |
UserIdsExactFilter | Group channels that contain members with one or more specified user IDs. You can enable this filter using the |
UserIdsIncludeFilter | Group channels that include one or more members with the specified user IDs. You can enable this filter using the |
NicknameContainsFilter | Group channels with members whose nicknames contain the specified value. You can enable this filter using the |
MetaDataOrderKeyFilter | Group channels with metadata containing an item with the specified value as its key. This filter is effective only when the metadata are sorted in alphabetical order. You can enable this filter using the |
PublicGroupChannelListQuery
A PublicGroupChannelListQuery
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.
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.
The following table shows all supported filters for PublicGroupChannelListQuery
to search for specific channels you want to retrieve. You can use any filters in a similar fashion with the sample code above.
List of filters
Name | Filters... |
---|---|
customTypesFilter | Group channels with one or more specified custom types. You can enable this filter using the |
customTypeStartsWithFilter | Group channels with a custom type that starts with the specified value. You can enable this filter using the |
channelNameContainsFilter | Group channels that contain the specified value in their names. You can enable this filter using the |
channelUrlsFilter | Group channels with one or more specified channel URLs. You can enable this filter using the |
superChannelFilter | Either super or nonsuper group channels. Using the |
MembershipFilter | Group channels with specified membership. Using the |
metaDataOrderKeyFilter | Group channels with metadata containing an item with the specified value as its key. This filter is effective only when the metadata are sorted in alphabetical order. You can enable this filter using the |
Search messages by keyword
Message search is a feature that retrieves a list of messages that contain a search query or a specified keyword.
Implement the MessageSearchQuery
to search messages in your Android client app. The query will retrieve a list of messages that contain a search term and meet the optional parameter values set by the MessageSearchQuery.Builder()
method.
Note: Puncutations and special characters are ignored while indexing, so unless they're being used for advanced search functionalities, they should be removed or replaced in the search term for best results.
You can create the query instance in two ways. First, you can do so with the default values.
Or, you can create an instance by changing those values to your preference.
The query will retrieve a list of matched messages. Calling the builder method again will return the next page of the results.
Use the hasNext()
method to see if there is a next page.
Use the isLoading()
method to see if the search results are loading.
Advanced search
Advanced search allows the SDK to create and support complicated search conditions, improving search results. Search functionalities such as wildcard, fuzzy search, logical operators, and synonym search are supported for the keyword
parameter. You can use these functionalities by setting advancedQuery
to true. See the advanced search section in our Platform API Docs for more information.
-
Wildcard: Include
?
or*
in search terms.?
matches a single character while*
can match zero or more characters. -
Fuzzy search: Add
~
at the end of search terms. Fuzzy search shows similar terms to the search term determined by a Levenshtein edit distance. If your search term is less than two characters, only exact matches are returned. If the search term has between three and five characters, only one character is edited. If the search term is longer than five characters, up to two characters are edited. -
Logical operators: Use
AND
andOR
to search for more than one term. The logical operators must be in uppercase. You can also use parentheses to group multiple search terms or specify target fields. If you want to look for search terms in not only the content of the message but also specified target fields of the message, such as custom type or data, you can specify the field and search term as a key-value item.
MessageQuerySearch.Builder()
You can build the query class using the following parameters which allow you to add various search options.
Parameter name | Type | Description |
---|---|---|
keyword | string | Specifies the search term. |
channelUrl | string | Specifies the URL of the target channel. |
channelCustomType | string | Specifies the custom channel type. |
limit | int | Specifies the number of messages to return per page. Acceptable values are 1 to 99, inclusive. (Default: 20) |
exactMatch | boolean | Determines whether to search for messages that exactly match the search term. If set to false, it will return partial matches that contain the search term. (Default: false) |
advancedQuery | boolean | Determines whether to perform a complex message search such as wildcard, fuzzy search, logical operators, and synonym search. (Default: false) |
messageTimestampFrom | long | Restricts the search scope to the messages sent after the specified value in Unix milliseconds format. This includes the messages sent exactly on the timestamp. (Default: 0) |
messageTimestampTo | long | Restricts the search scope to the messages sent before the specified value in Unix milliseconds format. This includes the messages sent exactly on the timestamp. (Default: Long.MAX_VALUE) |
order | enum | Determines by which field the results are sorted. Acceptable values are SCORE, which is a relevance score, and TIMESTAMP, which indicates the time when a message was created. (Default: SCORE) |
reverse | boolean | Determines whether to sort the results in reverse order. If set to false, they will be sorted in descending order. (Default: false) |
Generate thumbnails of a file message
When sending an image file, you can determine whether to create thumbnails of the image to fetch and render into your UI. You can specify up to 3 different dimensions to generate thumbnail images in, which can be convenient for supporting various display densities.
Note: Supported file types are files whose media type is
image/*
orvideo/*
. The Chat SDK doesn't support creating thumbnails when sending a file message via a file URL.
The sendFileMessage()
method requires passing a FileMessageParams
object as an argument to a parameter, containing an array of items which each specify the maximum values of width and height of a thumbnail image. The callback function subsequently returns a list of Thumbnail
items that each contain the URL of the generated thumbnail image file.
A thumbnail image is generated evenly to fit within the bounds of maxWidth
and maxHeight
, which are provided through the ThumbnailSize
constructor. Note that if the original image is smaller than the specified dimensions, the thumbnail isn't resized. getUrl()
returns the location of the generated thumbnail file within Sendbird server.
Track file upload progress using a handler
You can track the file upload progress by passing the SendFileMessageWithProgressHandler()
as an argument to a parameter when calling the sendFileMessage()
method.
Cancel an in-progress file upload
Using the cancelFileMessageUpload()
method, you can cancel an in-progress file upload while it's not completed yet. If the function operates successfully, true is returned.
Note: If you attempt to cancel the uploading after it is already completed, or canceled, or returned an error, the function returns false.
This file encryption feature prevents users without access from opening and reading encrypted files that have been shared within a group of users. When this feature is turned on, all types of sent files and thumbnail images will be first uploaded to Sendbird server, and then encrypted by AES256
.
In a group channel, encrypted files and thumbnail images will be decrypted and accessed securely only by the members. Anyone outside of the channel and application will not have access to those files and thumbnail images. The following explains how this data security works and what to do at the SDK level to apply it to your client apps.
The Sendbird system enables secure encryption and decryption of files by generating and distributing an opaque and unique encryption key for each user. An encryption key is managed internally by the system, and is valid for 3 days. It is generated every time the user logs in to Sendbird server through the Chat SDK, which then gets delivered to the Chat SDK from the server.
When the Chat SDK requests an encrypted file by its URL, the parameter auth should be added to the URL to access the file, which is specified with an encryption key of the user such as ?auth=RW5jb2RlIHaXMgdGV4eA==
. With the specified key in the auth, Sendbird server first decrypts the file, then checks if the user is a member of the group channel, and finally, allows the user to access and open the file in the channel.
This can be easily done by using the fileMessage.getUrl()
method, which automatically adds the parameter auth with an encryption key of the current user to the file URL, and returns the unique URL for the user.
Spam flood protection
This feature allows you to customize the number of messages a member can send in a group channel per second. By doing so, all excess messages will be deleted and only the number of messages allowed to be sent per member per second will be delivered. This feature protects your app from some members spamming others in the channel with the same messages.
Note: Our default system setting is five messages per second. This limit can be manually adjusted only from our side. Contact our sales team for further assistance.
Message auto-translation
It is possible for text messages to be sent in different languages through the Sendbird's auto-translation feature. When sending a text message, set a List
of language codes to a UserMessageParams
object and then pass the object as an argument to a parameter in the sendUserMessage()
method to request translated messages in the corresponding languages.
Note: Message auto-translation is powered by Google Cloud Translation API recognition engine. Find language codes supported by the engine in the Miscellaneous page or visit the Language Support page in Google Cloud Translation.
You can retrieve translations of a text message using the userMessage.getTranslations()
method which returns a Map
object containing the language codes and translations.
Message on-demand translation
Using the groupChannel.translateUserMessage()
method, you can allow your users to translate text messages into other languages when needed.
Note: Message on-demand translation is powered by Google Cloud Translation API recognition engine. Find language codes supported by the engine in the Miscellaneous page or visit the Language Support page in Google Cloud Translation.
Based on this method, you can implement features such as real-time or instant translation to your app. You can also implement to only translate a selected message into preferred languages.