Private messaging

Private messaging is a feature that allows sending a message in channel to one or more specific users, thereby limiting visibility to other users in that channel. If you want to inform 1 specific user in a channel with a system message for example, then private messaging is perfectly feature for it.

Possible use cases

Taxi app (like Uber) use case

In a taxi app where both the driver and the passenger share a channel, you could provide either of them with additional updates.

Alert the driver that the passenger is close by.
Alert the passenger of where the driver is.

Moderation use case

The system may wish to send a message to only a single user to alert them that there may be fraudulent activity from the another user in the channel.
Show a blocked user a message to let them know they have been suspended.

Marketplace use case

Show alternative listings to a potential buyer, thereby improving customer engagement.
Show a message the product is reserved for the user.

Sending a message with restricted visibility

In order to send a message with restricted visibility the user needs to have the CreateRestrictedVisibilityMessage permission.

// Get a channel
const channel = client.Channel("messaging", "ride-08467339");

// Send a message only visible to Jane
const message = await channel.sendMessage({
  text: "Hi Jane, your driver John will be at your location in 1 minute",
  type: "system",
  restricted_visibility: [ "Jane" ]
});

ctx := context.Background()

// Get a channel
channel := client.Channel("messaging", "ride-08467339")

// Send a message only visible to Jane
response, err := channel.SendMessage(ctx, &Message{
	Text: "Hi Jane, your driver John will be at your location in 1 minute",
    Type: MessageTypeSystem,
	RestrictedVisibility: []string{
		jane.ID,
	},
}, adminUser.ID)

# Get a channel
channel = client.channel("messaging", "ride-08467339")

# Send a message only visible to Jane
response = await channel.send_message({
    "text": "Hi Jane, your driver John will be at your location in 1 minute",
    "type": "system",
    "restricted_visibility": [ "jane" ]
}, admin_user["id"])

// Get a channel
$channel = $client.Channel("messaging", "general")

// Send a message only visible to Jane
$message = $channel->sendMessage([
	"text" => "Hi Jane, your driver John will be at your location in 1 minute",
    "type" => "system",
    "restricted_visibility" => [ "jane" ]
], $adminUser["id"]);

// Send a message only visible to Jane
List<String> restrictedUsers = Arrays.asList(jane.getId());
MessageRequestObject messageRequest =
    MessageRequestObject.builder()
        .text("Hi Jane, your driver John will be at your location in 1 minute")
        .type("system")
        .userId(adminUser.getId())
        .restrictedVisibility(restrictedUsers)
        .build();

Message message = Message.send(channel.getType(), channel.getId())
    .message(messageRequest)
    .request()
    .getMessage();

# Get a channel
channel = client.channel("messaging", "ride-08467339")

# Send a message only visible to Jane
message = channel.send_message(
{
    'text' => 'Hi Jane, your driver John will be at your location in 1 minute',
    'type' => 'system',
    'restricted_visibility' => [ 'jane' ]
}, admin_user[:id])

// Get a channel
var channel = await client.await CreateChannelAsync(createdByUserId: adminUser.Id,
    members: new[] { "jane", "john" }
)

// Send a message only visible to Jane
var restrictedToUsers = new[] { "jane" };
var messageRequest = new MessageRequest
{
    Text = "Hi Jane, your driver John will be at your location in 1 minute",
    Type = MessageRequestType.System,
    RestrictedVisibility = restrictedToUsers,
};
var response = await messageClient.SendMessageAsync(channel.Type, channel.Id, messageRequest, adminUser.Id);

Additional information

Pinning a restricted visibility message

Pinning a restricted visibility message to a channel is not allowed, simply because pinning a message is meant to bring attention to that message, that is not possible with a message that is only visible to a subset of users.

Unread counts

If a restricted visibility message is send to a channel and the user cannot see that message then the unread count will not be increased for that user. The unread count will be increased for users who can see the message.

Truncating and updating channels

When truncating or updating a channel, the user can choose to send a system message in the same request. However, this message cannot contain a list of restricted visibility users. The reason being is both operations send an event to all channel members. This event includes the optional message. All channel members need to be notified about the channel update or truncation, it is not possible to send a message with restricted visbility. If you want to send a message with restricted visibility, then the update or truncate the channel first, after that you can send a message with restricted visibility to the channel.

Pinned messages

Translation