Channels

Our channels enable developers to implement different types of chat messaging capabilities into their applications easily

Users can create and join channels where they will be able to participate and chat with other users. A channel can support up to 300,000 members and can contain an unlimited number of messages. Any message exchanged in the channels will be pushed to all other members of the channel in real-time.

Amity's Chat SDK supports the creations of 4 types of chat channels. Each type is designed to match a particular use-case for chat channels. Here's a table showing what features each channel offers:

Channel Types

Channel Type	Discoverable by	Message sending privileges	Moderation access
Community	All users and admins	Users and admins	All Moderation tools
Live	Only members and admins	Users and admins	All Moderation tools
Broadcast	All users and admins	Admins	Admin Moderation tools
Conversation	Only members	Users	No Moderation tools

Community

All community channels are visible on the Amity Social Cloud Console.

The community channel is our default channel type and can be discovered by all users and admins. It acts as a public chat channel that showcases all of the features that our SDK's have to offer.

Typical use cases:

• Team collaboration

• Online gaming

• Celebrity fan club

• Live streaming

• Any type of public chat

Live

All live channels are visible on the Amity Social Cloud Console.

Live channels offers the ability for users and admins to create channels with exclusive memberships. The live channel is identical to our Community channel in features with the caveat that users will not be able to discover the channel when querying for all channels unless they are already a member of it. However users and admins can still invite other users to join the channel.

Typical use cases:

• Healthcare

• Project Discussion

• Any type of private chat

Community and Live channel types can use our SDK moderation tools:

• Message and user flagging

• Muting/Unmuting users

• Banning/Unbanning users from channel

• Profanity filters

• Whitelisted URLs

• User rate-limiting

Broadcast

All broadcast channels are visible on the Amity Social Cloud Console.

The Broadcast channel is heavily adopted by corporate users who constantly promote or advertise their products, or make the announcement to drive awareness. Unlink other channel types, broadcast channels only allow admin users to send messages from Console, and everyone else in the channel will be under read-only mode.

Since this is a one-way communication channel, a tailored moderation tools are provided as well, for instance, users won't be able to flag message / user in the channel.

Typical use cases:

• Marketing & Advertising

• School / Government Announcements

Conversation

Conversation channels are NOT visible on the Amity Social Cloud Console.

The Conversation channel is our solution to 1-on-1 messaging. Unlike the other channel types, a Conversation channel can be created simply by knowing the userId of the user we want to converse with. Users can start conversations with any other user and only they will be able to see their conversation.

There are no moderation tools for Conversation channels, users will be able to converse freely with no oversight!

Typical use cases:

• Hospitality

• Financial Consultancy

• Customer Support

Channel Members

When a user joins a channel, they are able to observe and chat with other users in that channel. They are also automatically considered a member of that channel. The Chat SDK provides the ability to view which users are currently in the channel as well as invite other users to join the channel.

Channel Type	Discoverable by	Message sending privileges	Moderation access
Community	All users and admins	Users and admins	All Moderation tools
Live	Only members and admins	Users and admins	All Moderation tools
Broadcast	All users and admins	Admins	Admin Moderation tools
Conversation	Only members	Users	No Moderation tools

Each channel is identified by an unique channelId, which is any string that uniquely identifies the channel and is immutable through its lifetime. When creating channels, you can specify your own channelId, or leave it to Amity's Chat SDK to automatically generate one for you.

There can be only one and one only channel with a given channelId: an error will be thrown when trying to generate two channels with the same channelId.

There are three ways of obtaining a channel: via create, join, or get. They all return a LiveObject with the complete channel model. However, createChannel: guarantees that the requested channel is a new channel, whereas joinChannel: will attempt to join an existing channel. If there is a requirement to create a new channel, then use of createChannel: then call joinChannel:. Lastly calling getChannel: only gives you back the channel LiveObject, but it won't make the current user join said channel.

Channel management methods are contained in a EkoChannelRepository class. Before being able to call any channel method, you must initialize a repository instance using the EkoClient instance you created on setup:

import { ChannelRepository } from 'eko-sdk';
const channelRepo = new ChannelRepository();

Create Channel

EkoChannelRepository provides createChannel() method to create a new channel. It supports creating of 3 types of channels Community, Live and Conversation. Each channel type has specific builder classes which helps you to create that particular channel. Build your channel information first and then create the particular channel.

import { EkoChannelType } from 'eko-sdk';

const liveChannel = channelRepo.createChannel({
  channelId: 'channel1',
  type: EkoChannelType.Standard,
  userIds: [ 'user1', 'user2' ],
})
  .catch(err => {
    // Handle channel create error (non-unique channelID)
  });

liveChannel.once('dataUpdated', model => {
  console.log(`Channel created: ${model.channelId}`);
});

The above code creates a channel and notifies you through observer block. It first instantiates the EkoChannelRepository, a class that contain all channel related methods. Then it calls createChannel: to obtain the LiveObject and observe it in order to obtain the final channel model.

The EkoNotificationToken returned by the observe: is saved in self.channelToken, a strongly referenced property. This is needed in order to prevent the observe block to be released. Observe block can get called multiple time, when the underlying data for the channel updates. If you don't want to get notified, you can call channelToken.invalidate(). As soon as the token gets invalidated, observer is automatically removed from that channel.

In the case that there is already an existing channel with the same channelID, the LiveObject will notify you with an error object.

The channelId parameter in createChannel: can be nil: when this happens, the SDK will generate an unique channelId for this channel, ensuring no unique ID conflicts.

3 channel types can be created through SDK i.e Community, Live and Conversation. Creation of Private and Standard type has been removed. Creation of Broadcast channel type is not supported through the SDK. But for query, channelCollection: method supports all channel types including Broadcast, Private and Standard.

Create Conversation:

We do not currently support this method on Web, and will be working towards adding it shortly!

Conversation channel is unique based on its membership. When creating conversation the system will check if channel with the same membership already exists, if such channel already exists the system will return existing channel instead of creating a new one.

Join Channel

const liveChannel = channelRepo.joinChannel({
  channelId: 'channel2',
  type: EkoChannelType.Standard,
});

liveChannel.once('dataUpdated', data => {
  ...
});

joinChannel: is an idempotent method, this means it can be called multiple times throughout the lifecycle of the application, and you can expect this method to always return the same channel. Because of this, you can also use joinChannel: any time you need to fetch a channel, even if you know the user may already be in the channel.

Get Channel

In the case where you'd like to fetch a channel's data without joining, the getChannel: method can be used:

const liveChannel = channelRepo.channelForId('channel3');

liveChannel.once('dataUpdated', data => {
  ...
});

Channel Query

EkoChannelRepository provides a way to query list of channels using channelCollection() method. It returns a EkoCollection of all the matching channels available. This live collection returned will automatically update and notify you on any channel modifications.

SDK provides with 7 builder classes. EkoStandardChannelQueryBuilder, EkoPrivateChannelQueryBuilder, EkoByTypesChannelQueryBuilder, EkoBroadcastChannelQueryBuilder, EkoConversationChannelQueryBuilder, EkoCommunityChannelQueryBuilder and EkoLiveChannelQueryBuilder. These builder classes should be used to construct a query and then used alongside channelCollection method to fetch list of channels.

Depreciated: channelsForFilter(),channelsForFilter(_:includingTags:excludingTags:) method to query channels is now depreciated. SDK now doesnot support creation of Private & Standard channels but still supports query using EkoStandardChannelQueryBuilder EkoPrivateChannelQueryBuilder.

const channels = channelRepo.allChannels();

channels.on('dataUpdated', models => {
  // reload data
});

// unobserve data changes once you are finished
channels.removeAllListeners('dataUpdated');

If you use a UITableView or UICollectionView to display channel list data, the ideal location to reload table data is directly in the observe block of the LiveObject that you are displaying, as shown in the example above.

Channel Filtering

You can filter channels by various criteria such as includingTags, excludingTags, includeDeleted channels etc. All these filters are available in QueryBuilder classes for channel.

Metadata

Metadata is a general purpose data store that is automatically synchronized to all the channel members. It is meant as an elegant mechanism to store contextual information about a specific channel. The data can be any number of JSON key value pairs up to 100 kb. Example use cases include:

• Conversation title or cover photo

• Global conversation settings

Metadata is implemented with last writer wins semantics: multiple mutations by independent users to the metadata object will result in a single stored value. No locking, merging, or other coordination is performed across multiple writes on the data.

To set metadata, call the setMetadataForChannel: method:

channelRepo.setMetadata({
  channelId: 'channel1',
  metadata: { hello: 'world' },
})
  .then(() => {
    // success
  }).catch(error => {
    console.log('Metadata set fail');
  });

The completion block will be triggered with the outcome of the request. The latest metadata of the channel is always exposed as part of the metadata property on the channel model.

Display Name

Every channel contains an optional displayName property. This property is mainly used to identify the channel in push notifications, but it is also exposed to the application via EkoChannel object.

You can set a channel's displayName with the following method:

channelRepo.setDisplayName({
  channelId: 'channel1',
  displayName: 'Channel Eko',
})
  .then(() => {
    // success
  }).catch(error => {
    // handle error
  });

An optional completion callback is available to inform you on whether the request has succeeded or not.

Participation

All participation related methods in a channel falls under a separate EkoChannelParticipation class. Before calling any participation methods, you must ensure to first instantiate a repository instance using the EkoClient instance you created on setup and a valid channelId:

import { ChannelMembershipRepository } from 'eko-sdk';
const channelMembershipRepo = new ChannelMembershipRepository('channel1');

Also you can access a ChannelMembershipRepository instance by the membership property of a channel LiveObject model:

const channelMembershipRepo = liveChannel.model.membership;

Members Query

The participation membership provides a list of all members in the given channel as a LiveObject.

const members = channelMembershipRepo.members();
members.on('dataUpdated', models => {
  // reload member table
});

// unobserve data changes once you are finished
members.removeAllListeners('dataUpdated');

Manage Members

The participation membership also provides classes to add and remove members, as well as removing yourself as a member of the channel (leaving the channel).

// add 'user1' and 'user2' to this channel
channelMembershipRepo.addMembers({
  userIds: [ 'user1', 'user2' ],
})
  .then(() => {
    // success
  }).catch(error => {
    // handle error
  });

// remove 'user3' from this channel
channelMembershipRepo.removeUsers({
  userIds: [ 'user3' ],
})
  .then(() => {
    // success
  }).catch(error => {
    // handle error
  });

// leave this channel
channelMembershipRepo.leave().catch(error => { ... });

Reading Status And Unread Count

The EkoChannelRepository object exposes an totalUnreadCount property that reflects the number of messages that the current user has yet to read. This count is the sum of all the unreadCount channels properties where the user is already a member.

console.log(channelMembership.unreadCount) // 0

To let the server know when the current user is reading one channel, hence resetting that channel unreadCount to zero, the participation membership exposes the startReading and stopReading methods.

You can call both methods as much you want, the SDK takes care of multi-device management: therefore a user can read multiple channels, from one or multiple devices at once. In case of an abrupt disconnection (whether because the app was killed, or the internet went down etc) the SDK backend will automatically call the stopReading on the user behalf.

// start reading a channel
ChannelMembershipRepository.startReading()

// stop reading a channel
ChannelMembershipRepository.stopReading()

Moderation

EkoChannelModeration class provides various methods to moderate the users present in channel. You can ban/unban/mute users, assign roles or remove it from user.

Permission

You can check your permission in channel using hasPermission(permission:forChannel:_:) method from the "ekoclient"