Channel Members

Channel members are users who have been added to a channel and can participate in conversations. This page covers how to manage channel membership, including adding and removing members, controlling message history visibility, and managing member roles.

Adding and Removing Members

Adding Members

Using the addMembers() method adds the given users as members to a channel.

using GetStream;
using GetStream.Models;

var client = new StreamClient("{{ api_key }}", "{{ api_secret }}");
var chat = new ChatClient(client);

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        AddMembers = new List<ChannelMemberRequest>
        {
            new ChannelMemberRequest { UserID = "thierry" },
            new ChannelMemberRequest { UserID = "josh" }
        }
    });

Note: You can only add/remove up to 100 members at once.

Members can also be added when creating a channel:

// Members can be added when creating a channel
var resp = await chat.GetOrCreateChannelAsync("messaging", "my-channel-id",
    new ChannelGetOrCreateRequest
    {
        Data = new ChannelInput
        {
            CreatedByID = "user-1",
            Members = new List<ChannelMemberRequest>
            {
                new ChannelMemberRequest { UserID = "user-1" },
                new ChannelMemberRequest { UserID = "user-2" },
                new ChannelMemberRequest { UserID = "user-3" }
            }
        }
    });

Removing Members

Using the removeMembers() method removes the given users from the channel.

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        RemoveMembers = new List<string> { "thierry", "josh" }
    });

Leaving a Channel

Users can leave a channel without moderator-level permissions. Ensure channel members have the Leave Own Channel permission enabled.

channelClient.removeMembers(listOf("my_user_id")).enqueue()

You can familiarize yourself with all permissions in the Permissions section.

Hide History

When members join a channel, you can specify whether they have access to the channel's message history. By default, new members can see the history. Set hide_history to true to hide it for new members.

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        AddMembers = new List<ChannelMemberRequest>
        {
            new ChannelMemberRequest { UserID = "thierry" }
        },
        HideHistory = true
    });

Hide History Before a Specific Date

Alternatively, hide_history_before can be used to hide any history before a given timestamp while giving members access to later messages. The value must be a timestamp in the past in RFC 3339 format. If both parameters are defined, hide_history_before takes precedence over hide_history.

var cutoff = DateTime.UtcNow.AddDays(-7); // Last 7 days
await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        AddMembers = new List<ChannelMemberRequest>
        {
            new ChannelMemberRequest { UserID = "thierry" }
        },
        HideHistoryBefore = cutoff
    });

System Message Parameter

You can optionally include a message object when adding or removing members that client-side SDKs will use to display a system message. This works for both adding and removing members.

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        AddMembers = new List<ChannelMemberRequest>
        {
            new ChannelMemberRequest { UserID = "tommaso" }
        },
        Message = new MessageRequest
        {
            Text = "Tommaso joined the channel",
            UserID = "tommaso"
        }
    });

Adding and Removing Moderators

Using the addModerators() method adds the given users as moderators (or updates their role to moderator if already members), while demoteModerators() removes the moderator status.

Add Moderators

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        AddModerators = new List<string> { "thierry", "josh" }
    });

Remove Moderators

await chat.UpdateChannelAsync("messaging", channelId,
    new UpdateChannelRequest
    {
        DemoteModerators = new List<string> { "tommaso" }
    });

These operations can only be performed server-side, and a maximum of 100 moderators can be added or removed at once.

Member Custom Data

Custom data can be added at the channel member level. This is useful for storing member-specific information that is separate from user-level data. Ensure custom data does not exceed 5KB.

Adding Custom Data

// Add a member first
await chat.UpdateChannelAsync("messaging", "my-channel-id",
    new UpdateChannelRequest
    {
        AddMembers = new List<ChannelMemberRequest>
        {
            new ChannelMemberRequest { UserID = "user-2" }
        }
    });

// Set custom data on the member
await chat.UpdateMemberPartialAsync("messaging", "my-channel-id",
    new UpdateMemberPartialRequest
    {
        Set = new Dictionary<string, object>
        {
            ["hat"] = "blue" // Channel member custom data is separate from user custom data
        }
    });

Updating Member Data

Channel members can be partially updated. Only custom data and channel roles are eligible for modification. You can set or unset fields, either separately or in the same call.

// Set some fields
// Note: user_id is passed as a query parameter
await client.MakeRequestAsync<UpdateMemberPartialRequest, UpdateMemberPartialResponse>(
    "PATCH",
    "/api/v2/chat/channels/{type}/{id}/member",
    new Dictionary<string, string> { ["user_id"] = "user-2" },
    new UpdateMemberPartialRequest
    {
        Set = new Dictionary<string, object>
        {
            ["hat"] = "blue",
            ["score"] = 1000
        }
    },
    new Dictionary<string, string> { ["type"] = "messaging", ["id"] = "my-channel-id" });

// Unset some fields
await client.MakeRequestAsync<UpdateMemberPartialRequest, UpdateMemberPartialResponse>(
    "PATCH",
    "/api/v2/chat/channels/{type}/{id}/member",
    new Dictionary<string, string> { ["user_id"] = "user-2" },
    new UpdateMemberPartialRequest
    {
        Unset = new List<string> { "hat", "score" }
    },
    new Dictionary<string, string> { ["type"] = "messaging", ["id"] = "my-channel-id" });

// Set and unset in a single request
await client.MakeRequestAsync<UpdateMemberPartialRequest, UpdateMemberPartialResponse>(
    "PATCH",
    "/api/v2/chat/channels/{type}/{id}/member",
    new Dictionary<string, string> { ["user_id"] = "user-2" },
    new UpdateMemberPartialRequest
    {
        Set = new Dictionary<string, object> { ["hat"] = "blue" },
        Unset = new List<string> { "score" }
    },
    new Dictionary<string, string> { ["type"] = "messaging", ["id"] = "my-channel-id" });
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