channel creation for one to one chat using Pubnub in Ionic3

Question

I have implemented chat in Ionic3 using pubnub. Its working fine for a group chat.the channel used for group chat is "group1-ch". I have added my code here. I am facing some difficulties in developing a one to one chat.

PubnubService

import {Injectable, EventEmitter} from '@angular/core';
declare var PUBNUB;
type OnMessageFn = (message, envelope, channelOrGroup, time, channel) => void;

export enum PubNubEventType {
    MESSAGE,
    CONNECT,
    DISCONNECT,
    RECONNECT,
    PUBLISHED,
    HISTORY,
    PRESENCE
}

export class PubNubEvent {
    constructor(public type: PubNubEventType, channel:string, public value: any) {}
}

@Injectable()
export class PubNubService {

    pubnub:any;

    /**
     * Call this method after platform becomes to be ready
     */
    // init() {
    constructor() {

    }
    connectionuuid(uuid){
     this.pubnub = PUBNUB({

            subscribe_key: '*********************************',
            publish_key:   '*********************************',
            uuid:uuid,
            ssl: true,
            secret_key: '**************************************'

        });
    }

    subscribe(channel:string):EventEmitter<PubNubEvent> {
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.subscribe({
            channel : channel,
            withPresence: true,
            presence : (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.PRESENCE, channel, message));
            },
            message : (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.MESSAGE, channel, message));
            },
            connect: (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.CONNECT, channel, message));
            },
            disconnect: (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.DISCONNECT, channel, message));
            },
            reconnect: (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.RECONNECT, channel, message));
            },
            error: (error) => {
                eventEmitter.error(error);
            }, 
        });
        return eventEmitter;
    }

    publish(channel:string, message:any, store_in_history:boolean = true):EventEmitter<PubNubEvent> {
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.publish({
            channel: channel, 
            message: message, 
            store_in_history: store_in_history, 
            callback : (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.PUBLISHED, channel, message));
            },
            // Executes on a publish error.
            error: (error) => {
                eventEmitter.error(error);
            }
        });
        return eventEmitter;
    }

    individual_chat(channel:string, message:any, store_in_history:boolean = true):EventEmitter<PubNubEvent> {
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.publish({
            channel: channel,        
            message: message, 
            store_in_history: store_in_history, 
            callback : (message) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.PUBLISHED, channel, message));
            },
            // Executes on a publish error.
            error: (error) => {
                eventEmitter.error(error);
            }
        });
        return eventEmitter;
    }

    history(channel: string, count:number = 100, start:number = null, end:number = null, reverse:boolean = true, include_token: boolean = true):EventEmitter<PubNubEvent> {
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.history({
            channel: channel,
            callback: (messages) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.HISTORY, channel, messages));
            },
            error: (error) => {
                eventEmitter.error(error);
            },
            count: count,
            start: start,
            end: end,
            reverse: reverse,
            include_token: include_token
        });
        return eventEmitter;
    }

    here_now(channel: string, count:number = 100, start:number = null, end:number = null, reverse:boolean = true, include_token: boolean = true):EventEmitter<PubNubEvent>{
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.here_now({
        channel: channel,
        callback: (m) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.PRESENCE, channel, m));
            },
            error: (error) => {
                eventEmitter.error(error);
            },
            count: count,
            start: start,
            end: end,
            reverse: reverse,
            include_token: include_token
       });
        return eventEmitter;
    }
    where_now(channel: string, count:number = 100, start:number = null, end:number = null, reverse:boolean = true, include_token: boolean = true):EventEmitter<PubNubEvent>{
        let eventEmitter:EventEmitter<PubNubEvent> = new EventEmitter<PubNubEvent>();
        this.pubnub.where_now({
        uuid: channel,
        callback: (m) => {
                eventEmitter.emit(new PubNubEvent(PubNubEventType.PRESENCE, channel, m));
            },
            error: (error) => {
                eventEmitter.error(error);
            },
            count: count,
            start: start,
            end: end,
            reverse: reverse,
            include_token: include_token
       });
        return eventEmitter;
    }
}

My Requirement

1. Could anyone please tell me how to create "channel" for one to one chat?
2. How the receiver knows which channel the sender is using?

Thanks and Regards

Anand Raj

Answer 1

High Level Chat Invite Design Pattern

Let me use more specific names: Anand, Craig, John. Each user should subscribe to an inbound channel which they receive notification about invites:

• Anand subscribes to inbound.anand
• Craig subscribes to inbound.craig
• John subscribes to inbound.john

Now you can always know which channel to send (publish) an invitation to another inbound channel if you know the username you want to contact. You can send a message to invite them to chat and provide the channel as a separate value:

{
    "message": "Hi, this is Anand. I would like to invite you to chat with me.",
    "chat_channel": "abc123",
    "sender_id": "anand"
}

This is just a simple sample message and can be more complex but the point is, you want to send a message to the person you want to invite and provide a channel name (it can be a randomly generated string or something like andand_craig, as long as it is a unique channel name for Anand and Craig using unique usernames).

Your user interface would provide a way for the invited user to click either Accept or Reject buttons to respond to the invite.

• If Accept is clicked, then the invited user would publish a message back to inbox.anand or to the chat_channel that was provided, which anand would already be subscribed to, and then subscribe to the provided chat_channel, too, to begin chatting with anand.

This is fairly simplified design pattern but should provide some insights into how you can initiate conversations between two people or even a group of people.

For more details on recommended design patterns:

• Chat Fundamentals
• PubNub Best Practices Playbook

You can also look into using PubNub's ChatEngine framework which has builtin chat features. For Angular, see Simple Angular ChatEngine example.