Conversations’ messages and their relative statuses are generated from an immutable event store. To build up a conversation, we play through the events which are then projected into an ordered list of messages.

These events are available to the client either from the WebSocket or from a call to sdk.services.appMessaging.getConversationEvents().

The live WebSocket events are delivered to the app in real time and need to be applied to the local conversation message store. If there are any gaps, you can query a range of events using getConversationEvents(). The event payload is the same whether it’s received from the WebSocket or from this API method.

To query events:

// retrieve up to 100 events from position 0
sdk.services.appMessaging.getConversationEvents("5D21F17C-B2EC-4622-848E-5A2A916953EA", 0, 100)
    .then(events => {
        console.log("getConversationEvents() succeeded", events);
    })
    .catch(error => {
        console.error("getConversationEvents() failed", error);
    });

Apply events

After you have initially loaded up a conversation, it becomes your responsibility to process the incoming WebSocket events or query events from getConversationEvents() and update the messages accordingly.

There are three events that might need processing, depending on whether you intend to mark messages as delivered or read.

conversationMessage.sent

This event signifies that a new message has been posted to the conversation. If this message wasn't sent by you, you should send a status update marking this message as delivered. You should also add this message to your local message store.

You can identify the position to insert this message by looking at the sentEventid property on the messages in your message store, and the conversationEventId property on the sent event. Messages should be ordered based on this sequence.

conversationMessage.read

This event signifies that a someone has marked a message as read.

conversationMessage.delivered

This event signifies that someone has marked a message as delivered. Messages are automatically marked as delivered when you query messages with sdk.services.appMessaging.getMessages().

sdk.on("conversationMessageEvent", function (event) {
    
    // Check that we haven't processed this event already ....
    // when we call getMessages(), part of the response are 2 properties:
    // earliestEventId and latestEventId.
    // we need to maintain these and adjust when we query messages

    if(event.conversationEventId > earliestEventId ||
       event.conversationEventId < latestEventId){
        console.log("event already seen", event);
        return;
    }

    switch (event.name) {
        case "conversationMessage.sent":
        // add message to local conversation store 
        // also end a messageStatus update of delivered for this message
        // You can send another update of read when you display the message to the user
        break;

        case "conversationMessage.read":
        // update statusUpdates in locally stored message object (if found) to reflect message is read by event.payload.profileId
        break;

        case "conversationMessage.delivered":
        // update statusUpdates in locally stored message object (if found) to reflect message was delivered to event.payload.profileId
        break;
    }
});

StatusUpdates

Status updates are stored against a statusUpdates property on a message and is of the following structure. The status is either delivered or read.

If it’s read, we can assume it is also delivered.

{
    "alex": {
        "status": "read",
        "on": "2016-10-19T11:52:29.704Z"
    },
    "dave": {
        "status": "delivered",
        "on": "2016-10-19T11:00:29.704Z"
    },
}

IGetMessagesResponse

export interface IGetMessagesResponse {
    continuationToken?: number;
    earliestEventId?: number;
    latestEventId?: number;
    messages: IConversationMessage[];
}