Css Loader vs Style Loader Vs Sass-Loader

 The sass-loader will resolve the @import statements and include the imported Sass in the resulting CSS, hence the resulting CSS will probably not have any import statements. But the css-loader does not just handle imports. The three loaders you mention, do very different things and they are meant to be used together, although there are other loaders you could use, which would give a similar result.

1. sass-loader - Transforms Sass to CSS. (Input: Sass, Output: CSS)
2. css-loader - Transforms CSS to a JavaScript module. (Input: CSS, Output: JavaScript)
3. style-loader - Injects the CSS, that is exported by the JavaScript module, into a <style> tag at runtime. (Input: JavaScript, Output: JavaScript).

Note: The output of style-loader is only relevant if you are using CSS modules, which passes on the object that maps class names to local identifiers.

Live stream with WebRTC in your Laravel application

Introduction

My first attempt at WebRTC was to implement a video call feature within a Laravel Application. The implementation involved placing a call, showing an incoming call notification, and the ability of the receiver to accept the call. I wrote about it over here:

 

Adding Video Chat To Your Laravel App

Kofi Mupati ・ Nov 12 '20 ・ 11 min read

#laravel #vue #webrtc #videochat

One of my readers asked whether it was possible to build a live streaming application with WebRTC in a Laravel Application. I took up this challenge and even though WebRTC has limitations, I came up with a simple live streaming implementation.

We'll go through my implementation in this article.

Final Project Repository: https://github.com/Mupati/laravel-video-chat Note that this repository contains code for some other technical articles.

Requirements

• This tutorial assumes you know how to set up a new Laravel project with VueJs authentication. Create some users after setting up your project. You should be familiar with Laravel's broadcasting mechanism and have a fair idea of how WebSockets work. You may use this starter project I created: Laravel 8 Vue Auth Starter

• Set up a free pusher account on pusher.com

• Set up your ICE SERVER (TURN SERVER) details. This tutorial is a good guide. HOW TO INSTALL COTURN.

Project Setup

# Install needed packages
composer require pusher/pusher-PHP-server "~4.0"
npm install --save laravel-echo pusher-js simple-peer

Configuring Backend

• Add routes for streaming pages in routes/web.php. The routes will be used to visit the live stream page, start a live stream from the device camera, and generate a broadcast link for other authenticated users to view your live stream.

    Route::get('/streaming', 'App\Http\Controllers\WebrtcStreamingController@index');
    Route::get('/streaming/{streamId}', 'App\Http\Controllers\WebrtcStreamingController@consumer');
    Route::post('/stream-offer', 'App\Http\Controllers\WebrtcStreamingController@makeStreamOffer');
    Route::post('/stream-answer', 'App\Http\Controllers\WebrtcStreamingController@makeStreamAnswer');

• Uncomment BroadcastServiceProvider in config/app.php. This allows us to use Laravel's broadcasting system.

+ App\Providers\BroadcastServiceProvider::class
- //App\Providers\BroadcastServiceProvider::class 

• Create Dynamic Presence and Private Channel in routes/channels.php.

Authenticated users subscribe to both channels.
The presence channel is dynamically created with a streamId generated by the broadcaster. This way, we can detect all users who have joined the live broadcast.

Signaling information is exchanged between the broadcaster and the viewer through the private channel.

// Dynamic Presence Channel for Streaming
Broadcast::channel('streaming-channel.{streamId}', function ($user) {
    return ['id' => $user->id, 'name' => $user->name];
});

// Signaling Offer and Answer Channels
Broadcast::channel('stream-signal-channel.{userId}', function ($user, $userId) {
    return (int) $user->id === (int) $userId;
});

• Create StreamOffer and StreamAnswer events. Signaling information is broadcast on the stream-signal-channel-{userId} private channel we created early on.

The broadcaster sends an offer to a new user who joins the live stream when we emit the StreamOffer event and the viewer replies with an answer using the StreamAnswer event.

php artisan make:event StreamOffer
php artisan make:event StreamAnswer

• Add the following code to app/Events/StreamOffer.php.

<?php

namespace App\Events;

use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Broadcasting\PrivateChannel;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class StreamOffer implements ShouldBroadcast
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public $data;
    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct($data)
    {
        $this->data = $data;
    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return \Illuminate\Broadcasting\Channel|array
     */
    public function broadcastOn()
    {
        // stream offer can broadcast on a private channel
        return  new PrivateChannel('stream-signal-channel.' . $this->data['receiver']['id']);
    }
}

• Add the following code to app/Events/StreamAnswer.php.

<?php

namespace App\Events;

use Illuminate\Broadcasting\InteractsWithSockets;
use Illuminate\Broadcasting\PrivateChannel;
use Illuminate\Contracts\Broadcasting\ShouldBroadcast;
use Illuminate\Foundation\Events\Dispatchable;
use Illuminate\Queue\SerializesModels;

class StreamAnswer implements ShouldBroadcast
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public $data;
    /**
     * Create a new event instance.
     *
     * @return void
     */
    public function __construct($data)
    {
        $this->data = $data;
    }

    /**
     * Get the channels the event should broadcast on.
     *
     * @return \Illuminate\Broadcasting\Channel|array
     */
    public function broadcastOn()
    {
        return  new PrivateChannel('stream-signal-channel.' . $this->data['broadcaster']);
    }
}

• Create WebrtcStreamingController to handle the broadcasting, viewing, and signaling for the live stream.

php artisan make:controller WebrtcStreamingController

• Add the following to the WebrtcStreamingController

<?php

namespace App\Http\Controllers;

use App\Events\StreamAnswer;
use App\Events\StreamOffer;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;

class WebrtcStreamingController extends Controller
{

    public function index()
    {
        return view('video-broadcast', ['type' => 'broadcaster', 'id' => Auth::id()]);
    }

    public function consumer(Request $request, $streamId)
    {
        return view('video-broadcast', ['type' => 'consumer', 'streamId' => $streamId, 'id' => Auth::id()]);
    }

    public function makeStreamOffer(Request $request)
    {
        $data['broadcaster'] = $request->broadcaster;
        $data['receiver'] = $request->receiver;
        $data['offer'] = $request->offer;

        event(new StreamOffer($data));
    }

    public function makeStreamAnswer(Request $request)
    {
        $data['broadcaster'] = $request->broadcaster;
        $data['answer'] = $request->answer;
        event(new StreamAnswer($data));
    }
}

Methods in the WebrtcStreamingController

Let's explore what the methods in the controller are doing.

• index: This returns the view for the broadcaster. We pass a 'type': broadcaster and the user's ID into the view to help identify who the user is.
• consumer: It returns the view for a new user who wants to join the live stream. We pass a 'type': consumer, the 'streamId' we extract from the broadcasting link, and the user's ID.

• makeStreamOffer: It broadcasts an offer signal sent by the broadcaster to a specific user who just joined. The following data is sent:

  • broadcaster: The user ID of the one who initiated the live stream i.e the broadcaster
  • receiver: The ID of the user to whom the signaling offer is being sent.
  • offer: This is the WebRTC offer from the broadcaster.

• makeStreamAnswer: It sends an answer signal to the broadcaster to fully establish the peer connection.

  • broadcaster: The user ID of the one who initiated the live stream i.e the broadcaster.
  • answer: This is the WebRTC answer from the viewer after, sent after receiving an offer from the broadcaster.

Configuring Frontend

• Instantiate Laravel Echo and Pusher in resources/js/bootstrap.js by uncommenting the following block of code.

+ import Echo from 'laravel-echo';
+ window.Pusher = require('pusher-js');
+ window.Echo = new Echo({
+     broadcaster: 'pusher',
+     key: process.env.MIX_PUSHER_APP_KEY,
+     cluster: process.env.MIX_PUSHER_APP_CLUSTER,
+     forceTLS: true
+ });
- import Echo from 'laravel-echo';
- window.Pusher = require('pusher-js');
- window.Echo = new Echo({
-     broadcaster: 'pusher',
-     key: process.env.MIX_PUSHER_APP_KEY,
-     cluster: process.env.MIX_PUSHER_APP_CLUSTER,
-     forceTLS: true
-});

• Create resources/js/helpers.js. Add a getPermissions function to help with permission access for the microphone and camera. This method handles the video and audio permission that is required by browsers to make the video calls. It waits for the user to accept the permissions before we can proceed with the video call. We allow both audio and video. Read more on MDN Website.

export const getPermissions = () => {
    // Older browsers might not implement mediaDevices at all, so we set an empty object first
    if (navigator.mediaDevices === undefined) {
        navigator.mediaDevices = {};
    }

    // Some browsers partially implement media devices. We can't just assign an object
    // with getUserMedia as it would overwrite existing properties.
    // Here, we will just add the getUserMedia property if it's missing.
    if (navigator.mediaDevices.getUserMedia === undefined) {
        navigator.mediaDevices.getUserMedia = function(constraints) {
            // First get ahold of the legacy getUserMedia, if present
            const getUserMedia =
                navigator.webkitGetUserMedia || navigator.mozGetUserMedia;

            // Some browsers just don't implement it - return a rejected promise with an error
            // to keep a consistent interface
            if (!getUserMedia) {
                return Promise.reject(
                    new Error("getUserMedia is not implemented in this browser")
                );
            }

            // Otherwise, wrap the call to the old navigator.getUserMedia with a Promise
            return new Promise((resolve, reject) => {
                getUserMedia.call(navigator, constraints, resolve, reject);
            });
        };
    }
    navigator.mediaDevices.getUserMedia =
        navigator.mediaDevices.getUserMedia ||
        navigator.webkitGetUserMedia ||
        navigator.mozGetUserMedia;

    return new Promise((resolve, reject) => {
        navigator.mediaDevices
            .getUserMedia({ video: true, audio: true })
            .then(stream => {
                resolve(stream);
            })
            .catch(err => {
                reject(err);
                //   throw new Error(`Unable to fetch stream ${err}`);
            });
    });
};

• Create a component for the Broadcaster named Broadcaster.vue in resources/js/components/Broadcaster.vue.
  

  	<template>
  	<div class="container">
  	<div class="row">
  	<div class="col-md-8 offset-md-2">
  	<button class="btn btn-success" @click="startStream">
  	Start Stream</button
  	><br />
  	<p v-if="isVisibleLink" class="my-5">
  	Share the following streaming link: {{ streamLink }}
  	</p>
  	<video autoplay ref="broadcaster"></video>
  	</div>
  	</div>
  	</div>
  	</template>
  	<script>
  	import Peer from "simple-peer";
  	import { getPermissions } from "../helpers";
  	export default {
  	name: "Broadcaster",
  	props: [
  	"auth_user_id",
  	"env",
  	"turn_url",
  	"turn_username",
  	"turn_credential",
  	],
  	data() {
  	return {
  	isVisibleLink: false,
  	streamingPresenceChannel: null,
  	streamingUsers: [],
  	currentlyContactedUser: null,
  	allPeers: {}, // this will hold all dynamically created peers using the 'ID' of users who just joined as keys
  	};
  	},
  	computed: {
  	streamId() {
  	// you can improve streamId generation code. As long as we include the
  	// broadcaster's user id, we are assured of getting unique streamiing link everytime.
  	// the current code just generates a fixed streaming link for a particular user.
  	return `${this.auth_user_id}12acde2`;
  	},
  	streamLink() {
  	// just a quick fix. can be improved by setting the app_url
  	if (this.env === "production") {
  	return `https://laravel-video-call.herokuapp.com/streaming/${this.streamId}`;
  	} else {
  	return `http://127.0.0.1:8000/streaming/${this.streamId}`;
  	}
  	},
  	},
  	methods: {
  	async startStream() {
  	// const stream = await navigator.mediaDevices.getUserMedia({
  	// video: true,
  	// audio: true,
  	// });
  	// microphone and camera permissions
  	const stream = await getPermissions();
  	this.$refs.broadcaster.srcObject = stream;
  	this.initializeStreamingChannel();
  	this.initializeSignalAnswerChannel(); // a private channel where the broadcaster listens to incoming signalling answer
  	this.isVisibleLink = true;
  	},
  	peerCreator(stream, user, signalCallback) {
  	let peer;
  	return {
  	create: () => {
  	peer = new Peer({
  	initiator: true,
  	trickle: false,
  	stream: stream,
  	config: {
  	iceServers: [
  	{
  	urls: "stun:stun.stunprotocol.org",
  	},
  	{
  	urls: this.turn_url,
  	username: this.turn_username,
  	credential: this.turn_credential,
  	},
  	],
  	},
  	});
  	},
  	getPeer: () => peer,
  	initEvents: () => {
  	peer.on("signal", (data) => {
  	// send offer over here.
  	signalCallback(data, user);
  	});
  	peer.on("stream", (stream) => {
  	console.log("onStream");
  	});
  	peer.on("track", (track, stream) => {
  	console.log("onTrack");
  	});
  	peer.on("connect", () => {
  	console.log("Broadcaster Peer connected");
  	});
  	peer.on("close", () => {
  	console.log("Broadcaster Peer closed");
  	});
  	peer.on("error", (err) => {
  	console.log("handle error gracefully");
  	});
  	},
  	};
  	},
  	initializeStreamingChannel() {
  	this.streamingPresenceChannel = window.Echo.join(
  	`streaming-channel.${this.streamId}`
  	);
  	this.streamingPresenceChannel.here((users) => {
  	this.streamingUsers = users;
  	});
  	this.streamingPresenceChannel.joining((user) => {
  	console.log("New User", user);
  	// if this new user is not already on the call, send your stream offer
  	const joiningUserIndex = this.streamingUsers.findIndex(
  	(data) => data.id === user.id
  	);
  	if (joiningUserIndex < 0) {
  	this.streamingUsers.push(user);
  	// A new user just joined the channel so signal that user
  	this.currentlyContactedUser = user.id;
  	this.$set(
  	this.allPeers,
  	`${user.id}`,
  	this.peerCreator(
  	this.$refs.broadcaster.srcObject,
  	user,
  	this.signalCallback
  	)
  	);
  	// Create Peer
  	this.allPeers[user.id].create();
  	// Initialize Events
  	this.allPeers[user.id].initEvents();
  	}
  	});
  	this.streamingPresenceChannel.leaving((user) => {
  	console.log(user.name, "Left");
  	// destroy peer
  	this.allPeers[user.id].getPeer().destroy();
  	// delete peer object
  	delete this.allPeers[user.id];
  	// if one leaving is the broadcaster set streamingUsers to empty array
  	if (user.id === this.auth_user_id) {
  	this.streamingUsers = [];
  	} else {
  	// remove from streamingUsers array
  	const leavingUserIndex = this.streamingUsers.findIndex(
  	(data) => data.id === user.id
  	);
  	this.streamingUsers.splice(leavingUserIndex, 1);
  	}
  	});
  	},
  	initializeSignalAnswerChannel() {
  	window.Echo.private(`stream-signal-channel.${this.auth_user_id}`).listen(
  	"StreamAnswer",
  	({ data }) => {
  	console.log("Signal Answer from private channel");
  	if (data.answer.renegotiate) {
  	console.log("renegotating");
  	}
  	if (data.answer.sdp) {
  	const updatedSignal = {
  	...data.answer,
  	sdp: `${data.answer.sdp}\n`,
  	};
  	this.allPeers[this.currentlyContactedUser]
  	.getPeer()
  	.signal(updatedSignal);
  	}
  	}
  	);
  	},
  	signalCallback(offer, user) {
  	axios
  	.post("/stream-offer", {
  	broadcaster: this.auth_user_id,
  	receiver: user,
  	offer,
  	})
  	.then((res) => {
  	console.log(res);
  	})
  	.catch((err) => {
  	console.log(err);
  	});
  	},
  	},
  	};
  	</script>
  	<style scoped>
  	</style>

  view rawBroadcaster.vue hosted with ❤ by GitHub

• Create a component for the Viewer named Viewer.vue in resources/js/components/Viewer.vue.
  

  	<template>
  	<div class="container">
  	<div class="row">
  	<div class="col-md-8 offset-md-2">
  	<button class="btn btn-success" @click="joinBroadcast">
  	Join Stream</button
  	><br />
  	<video autoplay ref="viewer"></video>
  	</div>
  	</div>
  	</div>
  	</template>
  	<script>
  	import Peer from "simple-peer";
  	export default {
  	name: "Viewer",
  	props: [
  	"auth_user_id",
  	"stream_id",
  	"turn_url",
  	"turn_username",
  	"turn_credential",
  	],
  	data() {
  	return {
  	streamingPresenceChannel: null,
  	broadcasterPeer: null,
  	broadcasterId: null,
  	};
  	},
  	methods: {
  	joinBroadcast() {
  	this.initializeStreamingChannel();
  	this.initializeSignalOfferChannel(); // a private channel where the viewer listens to incoming signalling offer
  	},
  	initializeStreamingChannel() {
  	this.streamingPresenceChannel = window.Echo.join(
  	`streaming-channel.${this.stream_id}`
  	);
  	},
  	createViewerPeer(incomingOffer, broadcaster) {
  	const peer = new Peer({
  	initiator: false,
  	trickle: false,
  	config: {
  	iceServers: [
  	{
  	urls: "stun:stun.stunprotocol.org",
  	},
  	{
  	urls: this.turn_url,
  	username: this.turn_username,
  	credential: this.turn_credential,
  	},
  	],
  	},
  	});
  	// Add Transceivers
  	peer.addTransceiver("video", { direction: "recvonly" });
  	peer.addTransceiver("audio", { direction: "recvonly" });
  	// Initialize Peer events for connection to remote peer
  	this.handlePeerEvents(
  	peer,
  	incomingOffer,
  	broadcaster,
  	this.removeBroadcastVideo
  	);
  	this.broadcasterPeer = peer;
  	},
  	handlePeerEvents(peer, incomingOffer, broadcaster, cleanupCallback) {
  	peer.on("signal", (data) => {
  	axios
  	.post("/stream-answer", {
  	broadcaster,
  	answer: data,
  	})
  	.then((res) => {
  	console.log(res);
  	})
  	.catch((err) => {
  	console.log(err);
  	});
  	});
  	peer.on("stream", (stream) => {
  	// display remote stream
  	this.$refs.viewer.srcObject = stream;
  	});
  	peer.on("track", (track, stream) => {
  	console.log("onTrack");
  	});
  	peer.on("connect", () => {
  	console.log("Viewer Peer connected");
  	});
  	peer.on("close", () => {
  	console.log("Viewer Peer closed");
  	peer.destroy();
  	cleanupCallback();
  	});
  	peer.on("error", (err) => {
  	console.log("handle error gracefully");
  	});
  	const updatedOffer = {
  	...incomingOffer,
  	sdp: `${incomingOffer.sdp}\n`,
  	};
  	peer.signal(updatedOffer);
  	},
  	initializeSignalOfferChannel() {
  	window.Echo.private(`stream-signal-channel.${this.auth_user_id}`).listen(
  	"StreamOffer",
  	({ data }) => {
  	console.log("Signal Offer from private channel");
  	this.broadcasterId = data.broadcaster;
  	this.createViewerPeer(data.offer, data.broadcaster);
  	}
  	);
  	},
  	removeBroadcastVideo() {
  	console.log("removingBroadcast Video");
  	alert("Livestream ended by broadcaster");
  	const tracks = this.$refs.viewer.srcObject.getTracks();
  	tracks.forEach((track) => {
  	track.stop();
  	});
  	this.$refs.viewer.srcObject = null;
  	},
  	},
  	};
  	</script>
  	<style scoped>
  	</style>

  view rawViewer.vue hosted with ❤ by GitHub

Explanation of the Broadcaster and Viewer components.

The following video explains the call logic on the client-side from the perspective of both Broadcaster and Viewers.

• Register the Broadcaster.vue and Viewer.vue components in resources/js/app.js

//  Streaming Components
Vue.component("broadcaster", require("./components/Broadcaster.vue").default);
Vue.component("viewer", require("./components/Viewer.vue").default);

• Create the video broadcast view in resources/views/video-broadcast.blade.php
  

  	@extends('layouts.app')
  	@section('content')
  	@if ($type === 'broadcaster')
  	<broadcaster :auth_user_id="{{ $id }}" env="{{ env('APP_ENV') }}"
  	turn_url="{{ env('TURN_SERVER_URL') }}" turn_username="{{ env('TURN_SERVER_USERNAME') }}"
  	turn_credential="{{ env('TURN_SERVER_CREDENTIAL') }}" />
  	@else
  	<viewer stream_id="{{ $streamId }}" :auth_user_id="{{ $id }}"
  	turn_url="{{ env('TURN_SERVER_URL') }}" turn_username="{{ env('TURN_SERVER_USERNAME') }}"
  	turn_credential="{{ env('TURN_SERVER_CREDENTIAL') }}" />
  	@endif
  	@endsection

  view rawvideo-broadcast.blade.php hosted with ❤ by GitHub

• Update env variables. Insert your Pusher API keys
  
  

APP_ENV=

BROADCAST_DRIVER=pusher

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=
PUSHER_APP_CLUSTER=

TURN_SERVER_URL=
TURN_SERVER_USERNAME=
TURN_SERVER_CREDENTIAL=

Live Stream Demo

Final Thoughts

The logic for this live streaming application can be likened to a group video call where only one person's stream is seen.

The stream of the broadcaster is rendered on the viewers' browser but the broadcaster doesn't receive anything from the viewers after exchanging the signaling information which is required in WebRTC.

This looks like a star topology and there is a limitation on how many peers can be connected to a single user.

I want to explore the option of turning some of the viewers into broadcasters after the initial broadcaster's peer has connected to about 4 users.

The goal is to rebroadcast the stream they received from the original broadcaster.

Is it possible? I can't tell. This will be an interesting challenge to explore.

Stay tuned!!!.

Link : https://dev.to/mupati/live-stream-with-webrtc-in-your-laravel-application-2kl3