Channel memberships

PubNub allows you to store the association between users and channels so clients can get channel memberships for a user, or show members in a channel. Memberships are user-channel associations, not subscriptions. Users don't need to join a channel to subscribe and start exchanging messages on it, but it can be a helpful mechanism for your application to use.

Refer to Channel Membership to learn more about working with channel metadata.

User ID / UUID

User ID is also referred to as UUID/uuid in some APIs and server responses but holds the value of the userId parameter you set during initialization.

Add members to a channel

To add one or more users to a single channel, as you might do when adding a new team channel, add those users to the channel's members with setChannelMembers(), like so:

You can also use setChannelMembers() to update the custom metadata for existing channel members.

JavaScript

pubnub.objects.setChannelMembers({
  channel: "channel-1",
  uuids: [
    "johndoe_1",
    { id: "janedoe_1", custom: { trialPeriod: true } },
  ],
});

Swift

let newMembership = PubNubMembershipMetadataBase(
  uuidMetadataId: "janedoe_1", channelMetadataId: "channel-1"
)

pubnub.setMemberships(
  channel: newMembership.channelMetadataId,
  uuids: [newMembership]
) { result in
  switch result {
  case let .success(response):
    print("The channel memberships for the User ID \(response.memberships)")
    if let nextPage = response.next {
      print("The next page used for pagination: \(nextPage)")
    }
  case let .failure(error):

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Objective-C

NSArray<NSDictionary *> *uuids = @[
  @{ @"uuid": @"johndoe_1" }
  @{ @"uuid": @"janedoe_1", @"custom": @{ @"trialPeriod": @YES } }
];

self.client.objects().setChannelMembers(@"channel-1")
    .uuids(uuids)
    .includeFields(PNChannelMemberCustomField | PNChannelMemberUserField)
    .performWithCompletion(^(PNManageChannelMembersStatus *status) {
        if (!status.isError) {
            /**
             * Channel's members successfully set.
             * Result object has following information:
             *   result.data.members - List of existing channel's members.
             *   result.data.next - Random string returned from the server, indicating a specific position in a data set. Used for forward pagination, it fetches the next page, allowing you to continue from where you left off.

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C#

List<PNChannelMember> setMemberChannelList = new List<PNChannelMember>();
if (!string.IsNullOrEmpty(setMemberChUuid))
{
    setMemberChannelList.Add(new PNChannelMember() { Uuid = "johndoe_1" } );
    setMemberChannelList.Add(new PNChannelMember() { Uuid = "janedoe_1", Custom = new Dictionary<string, object>() { { "trialPeriod", true } } });
}
PNResult<PNChannelMembersResult> setChannelMembersResponse = await pubnub.SetChannelMembers()
    .Channel(setmemberChMetadataId)
    .Uuids(setMemberChannelList)
    .Include(new PNChannelMemberField[] { PNChannelMemberField.CUSTOM, PNChannelMemberField.UUID, PNChannelMemberField.UUID_CUSTOM })
    .IncludeCount(true)
    .ExecuteAsync();
PNChannelMembersResult setChannelMembersResult = setChannelMembersResponse.Result;
PNStatus status2 = setChannelMembersResponse.Status;

Remove channel members

You can remove one or more users from a single channel by providing the channel ID and a list of users. The code below deletes the membership to my_channel_2 for the users johndoe_1 and janedoe_1.

JavaScript

pubnub.objects.removeChannelMembers({
        channel: "my_channel_2",
        uuids: ["johndoe_1", "janedoe_1"]
    }
);

Objective-C

self.client.objects().removeChannelMembers(@"my_channel_2")
    .uuids(@[@"johndoe_1", @"janedoe_1"])
    .includeFields(PNChannelMemberCustomField | PNChannelMemberUserField)
    .performWithCompletion(^(PNManageChannelMembersStatus *status) {
        if (!status.isError) {
            /**
             * Channel's members successfully removed.
             * Result object has following information:
             *   result.data.members - List of channel's existing members.
             *   result.data.next - Random string returned from the server, indicating a specific position in a data set. Used for forward pagination, it fetches the next page, allowing you to continue from where you left off.
             *   result.data.prev - Random string returned from the server, indicating a specific position in a data set. Used for backward pagination, it fetches the previous page, enabling access to earlier data.
             *   result.data.totalCount - Total number of channel's members.
             */
        } else {
            /**

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Java

pubnub.removeChannelMembers()
    .channel("my_channel_2")
    .uuids(Arrays.asList(PNUUID.uuid("johndoe_1"), PNUUID.uuid("janedoe_1")))
    .async(result -> { /* check result */ });

C#

List<string> removeChannelMemberList = new List<string>();
removeChannelMemberList.Add("johndoe_1");
removeChannelMemberList.Add("janedoe_1");

PNResult<PNChannelMembersResult> removeChannelMembersResponse = await pubnub.RemoveChannelMembers()
    .Channel("my_channel_2")
    .Uuids(removeChannelMemberList)
    .Include(new PNChannelMemberField[] { PNChannelMemberField.CUSTOM, PNChannelMemberField.UUID, PNChannelMemberField.UUID_CUSTOM })
    .IncludeCount(true)
    .ExecuteAsync();
PNChannelMembersResult removeChannelMembersResult = removeChannelMembersResponse.Result;
PNStatus status = removeChannelMembersResponse.Status;

Add channel memberships

To add one user to several channels, perhaps as part of a new-user onboarding process, add those channels to the user's memberships with setMemberships(), like so:

JavaScript

pubnub.objects.setMemberships({
  channels: [ "channel-1", { id: "channel-2", custom: { starred: true } }]
});

Swift

let newMembership = PubNubMembershipMetadataBase(
  uuidMetadataId: "my_user", channelMetadataId: "channel-1"
)

pubnub.setMemberships(
  uuid: newMembership.uuidMetadataId,
  channels: [newMembership]
) { result in
  switch result {
  case let .success(response):
    print("The channel memberships for the User ID \(response.memberships)")
    if let nextPage = response.next {
      print("The next page used for pagination: \(nextPage)")
    }
  case let .failure(error):

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Objective-C

NSArray<NSDictionary *> *channels = @[
  @{ @"channel": @"channel-1" },
  @{ @"channel": @"channel-2", @"custom": @{ @"starred": @YES } }
];

self.client.objects().setMemberships()
    .uuid(@"uuid")
    .channels(channels)
    .includeCount(YES)
    .limit(40)
    .includeFields(NMembershipCustomField | PNMembershipChannelField)
    .performWithCompletion(^(PNManageMembershipsStatus *status) {
        if (!status.isError) {
            /**
             * UUID's memberships successfully set.

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C#

List<PNMembership> setMembershipChannelMetadataIdList = new List<PNMembership>();
if (!string.IsNullOrEmpty(seMembershipChannelMetaId))
{
    setMembershipChannelMetadataIdList.Add(new PNMembership() { Channel = "channel-1" });
    setMembershipChannelMetadataIdList.Add(new PNMembership() { Channel = "channel-2", Custom = new Dictionary<string, object>() { { "starred", true } } });
}

PNResult<PNMembershipsResult> setMembershipsResponse = await pubnub.SetMemberships()
    .Uuid("my-uuid")
    .Channels(setMembershipChannelMetadataIdList)
    .Include(new PNMembershipField[] { PNMembershipField.CUSTOM, PNMembershipField.CHANNEL, PNMembershipField.CHANNEL_CUSTOM })
    .IncludeCount(true)
    .ExecuteAsync();
PNMembershipsResult setMembershipsResult = setMembershipsResponse.Result;
PNStatus status = setMembershipsResponse.Status;

Remove channel memberships

You can remove a single user from one or more channels, effectively deleting a membership relation between the user and the channels. The code below removes the current user from the channel my_channel_2.

JavaScript

pubnub.objects.removeMemberships({
  channels: ["my_channel_2"]
});

Objective-C

self.client.objects().removeMemberships()
    .uuid(@"uuid")
    .channels(@"my_channel_2")
    .includeFields(PNMembershipCustomField | PNMembershipChannelField)
    .performWithCompletion(^(PNManageMembershipsStatus *status) {
        if (!status.isError) {
            /**
             * UUID's memberships successfully removed.
             * Result object has following information:
             *   status.data.memberships - List of UUID's existing memberships.
             *   status.data.next - Random string returned from the server, indicating a specific position in a data set. Used for forward pagination, it fetches the next page, allowing you to continue from where you left off.
             *   status.data.prev - Random string returned from the server, indicating a specific position in a data set. Used for backward pagination, it fetches the previous page, enabling access to earlier data.
             *   status.data.totalCount - Total number of UUID's memberships.
             */
        } else {

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Java

pubnub.removeMemberships()
    .channelMemberships(Collections.singletonList(PNChannelMembership.channel("my_channel_2")))
    .async(result -> { /* check result */ });

C#

List<string> removeMembershipList = new List<string>();
if (!string.IsNullOrEmpty(removeMembershipChannelMetaId))
{
    removeMembershipList.Add("my_channel_2");
}

PNResult<PNMembershipsResult> removeMembershipsResponse = await pubnub.RemoveMemberships()
    .Uuid("uuid")
    .Channels(removeMembershipList)
    .Include(new PNMembershipField[] { PNMembershipField.CUSTOM, PNMembershipField.CHANNEL, PNMembershipField.CHANNEL_CUSTOM })
    .IncludeCount(true)
    .ExecuteAsync();
PNMembershipsResult removeMembershipsResult = removeMembershipsResponse.Result;
PNStatus status2 = removeMembershipsResponse.Status;

Membership events

Membership events are generated when memberships are set or removed from the objects database. Object events are disabled by default on new keys. You can enable or disable these events from your key settings in the Admin Portal.

Event	Description	Event channel
Membership Set	User-channel association is created or updated.	These events are published on {uuid} and {channel}.
Membership Removed	User-channel association is deleted.	These events are published on {uuid} and {channel}.

Membership set event:

{
   "channel":"ch-1",
   "message":{
      "event":"set",
      "type":"membership",
      "data":{
         "channel":{
            "id":"ch-1"
         },
         "uuid":{
            "id":"uuid-1"
         },
         "custom":null,
         "updated":"2020-04-17T19:13:59.40962853Z",
         "eTag":"AY39mJKK//C0VA"

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Membership removed event:

{
   "channel":"ch-1",
   "message":{
      "event":"removed",
      "type":"membership",
      "data":{
         "channel":{
            "id":"ch-1"
         },
         "uuid":{
            "id":"uuid-1"
         },
         "custom":null,
         "updated":"2020-04-17T19:13:59.40962853Z",
         "eTag":"AY39mJKK//C0VA"

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