5G-Loading-Bay-Web/public/webrtcstreamer.js

var WebRtcStreamer = (function () {

	/** 
	 * Interface with WebRTC-streamer API
	 * @constructor
	 * @param {string} videoElement - id of the video element tag
	 * @param {string} srvurl -  url of webrtc-streamer (default is current location)
	 */
	var WebRtcStreamer = function WebRtcStreamer(videoElement, srvurl) {
		if (typeof videoElement === "string") {
			this.videoElement = document.getElementById(videoElement);
		} else {
			this.videoElement = videoElement;
		}
		this.srvurl = srvurl || location.protocol + "//" + window.location.hostname + ":" + window.location.port;
		this.pc = null;

		this.mediaConstraints = {
			offerToReceiveAudio: true,
			offerToReceiveVideo: true
		};

		this.iceServers = null;
		this.earlyCandidates = [];
	}

	WebRtcStreamer.prototype._handleHttpErrors = function (response) {
		if (!response.ok) {
			throw Error(response.statusText);
		}
		return response;
	}

	/** 
	 * Connect a WebRTC Stream to videoElement 
	 * @param {string} videourl - id of WebRTC video stream
	 * @param {string} audiourl - id of WebRTC audio stream
	 * @param {string} options  -  options of WebRTC call
	 * @param {string} stream   -  local stream to send
	 * @param {string} prefmime -  prefered mime
	 */
	WebRtcStreamer.prototype.connect = function (videourl, audiourl, options, localstream, prefmime) {
		this.disconnect();

		// getIceServers is not already received
		if (!this.iceServers) {
			console.log("Get IceServers");

			fetch(this.srvurl + "/api/getIceServers")
				.then(this._handleHttpErrors)
				.then((response) => (response.json()))
				.then((response) => this.onReceiveGetIceServers(response, videourl, audiourl, options, localstream, prefmime))
				.catch((error) => this.onError("getIceServers " + error))

		} else {
			this.onReceiveGetIceServers(this.iceServers, videourl, audiourl, options, localstream, prefmime);
		}
	}

	/** 
	 * Disconnect a WebRTC Stream and clear videoElement source
	 */
	WebRtcStreamer.prototype.disconnect = function () {
		if (this.videoElement?.srcObject) {
			this.videoElement.srcObject.getTracks().forEach(track => {
				track.stop()
				this.videoElement.srcObject.removeTrack(track);
			});
		}
		if (this.pc) {
			fetch(this.srvurl + "/api/hangup?peerid=" + this.pc.peerid)
				.then(this._handleHttpErrors)
				.catch((error) => this.onError("hangup " + error))


			try {
				this.pc.close();
			} catch (e) {
				console.log("Failure close peer connection:" + e);
			}
			this.pc = null;
		}
	}

	WebRtcStreamer.prototype.filterPreferredCodec = function (sdp, prefmime) {
		const lines = sdp.split('\n');
		const [prefkind, prefcodec] = prefmime.toLowerCase().split('/');
		let currentMediaType = null;
		let sdpSections = [];
		let currentSection = [];

		// Group lines into sections
		lines.forEach(line => {
			if (line.startsWith('m=')) {
				if (currentSection.length) {
					sdpSections.push(currentSection);
				}
				currentSection = [line];
			} else {
				currentSection.push(line);
			}
		});
		sdpSections.push(currentSection);

		// Process each section
		const processedSections = sdpSections.map(section => {
			const firstLine = section[0];
			if (!firstLine.startsWith('m=' + prefkind)) {
				return section.join('\n');
			}

			// Get payload types for preferred codec
			const rtpLines = section.filter(line => line.startsWith('a=rtpmap:'));
			const preferredPayloads = rtpLines
				.filter(line => line.toLowerCase().includes(prefcodec))
				.map(line => line.split(':')[1].split(' ')[0]);

			if (preferredPayloads.length === 0) {
				return section.join('\n');
			}

			// Modify m= line to only include preferred payloads
			const mLine = firstLine.split(' ');
			const newMLine = [...mLine.slice(0, 3), ...preferredPayloads].join(' ');

			// Filter related attributes
			const filteredLines = section.filter(line => {
				if (line === firstLine) return false;
				if (line.startsWith('a=rtpmap:')) {
					return preferredPayloads.some(payload => line.startsWith(`a=rtpmap:${payload}`));
				}
				if (line.startsWith('a=fmtp:') || line.startsWith('a=rtcp-fb:')) {
					return preferredPayloads.some(payload => line.startsWith(`a=${line.split(':')[0].split('a=')[1]}:${payload}`));
				}
				return true;
			});

			return [newMLine, ...filteredLines].join('\n');
		});

		return processedSections.join('\n');
	}

	/*
	 * GetIceServers callback
	 */
	WebRtcStreamer.prototype.onReceiveGetIceServers = function (iceServers, videourl, audiourl, options, stream, prefmime) {
		this.iceServers = iceServers;
		this.pcConfig = iceServers || {
			"iceServers": []
		};
		try {
			this.createPeerConnection();

			let callurl = this.srvurl + "/api/call?peerid=" + this.pc.peerid + "&url=" + encodeURIComponent(videourl);
			if (audiourl) {
				callurl += "&audiourl=" + encodeURIComponent(audiourl);
			}
			if (options) {
				callurl += "&options=" + encodeURIComponent(options);
			}

			if (stream) {
				this.pc.addStream(stream);
			}

			// clear early candidates
			this.earlyCandidates.length = 0;

			// create Offer
			this.pc.createOffer(this.mediaConstraints).then((sessionDescription) => {
				console.log("Create offer:" + JSON.stringify(sessionDescription));

				console.log(`video codecs:${Array.from(new Set(RTCRtpReceiver.getCapabilities("video")?.codecs?.map(codec => codec.mimeType)))}`)
				console.log(`audio codecs:${Array.from(new Set(RTCRtpReceiver.getCapabilities("audio")?.codecs?.map(codec => codec.mimeType)))}`)

				if (prefmime != undefined) {
					//set prefered codec
					let [prefkind] = prefmime.split('/');
					if (prefkind != "video" && prefkind != "audio") {
						prefkind = "video";
						prefmime = prefkind + "/" + prefmime;
					}
					console.log("sdp:" + sessionDescription.sdp);
					sessionDescription.sdp = this.filterPreferredCodec(sessionDescription.sdp, prefmime);
					console.log("sdp:" + sessionDescription.sdp);
				}


				this.pc.setLocalDescription(sessionDescription)
					.then(() => {
						fetch(callurl, {
								method: "POST",
								body: JSON.stringify(sessionDescription)
							})
							.then(this._handleHttpErrors)
							.then((response) => (response.json()))
							.catch((error) => this.onError("call " + error))
							.then((response) => this.onReceiveCall(response))
							.catch((error) => this.onError("call " + error))

					}, (error) => {
						console.log("setLocalDescription error:" + JSON.stringify(error));
					});

			}, (error) => {
				alert("Create offer error:" + JSON.stringify(error));
			});

		} catch (e) {
			this.disconnect();
			alert("connect error: " + e);
		}
	}


	WebRtcStreamer.prototype.getIceCandidate = function () {
		fetch(this.srvurl + "/api/getIceCandidate?peerid=" + this.pc.peerid)
			.then(this._handleHttpErrors)
			.then((response) => (response.json()))
			.then((response) => this.onReceiveCandidate(response))
			.catch((error) => this.onError("getIceCandidate " + error))
	}

	/*
	 * create RTCPeerConnection 
	 */
	WebRtcStreamer.prototype.createPeerConnection = function () {
		console.log("createPeerConnection  config: " + JSON.stringify(this.pcConfig));
		this.pc = new RTCPeerConnection(this.pcConfig);
		let pc = this.pc;
		pc.peerid = Math.random();

		pc.onicecandidate = (evt) => this.onIceCandidate(evt);
		pc.onaddstream = (evt) => this.onAddStream(evt);
		pc.oniceconnectionstatechange = (evt) => {
			console.log("oniceconnectionstatechange  state: " + pc.iceConnectionState);
			if (this.videoElement) {
				if (pc.iceConnectionState === "connected") {
					this.videoElement.style.opacity = "1.0";
				} else if (pc.iceConnectionState === "disconnected") {
					this.videoElement.style.opacity = "0.25";
				} else if ((pc.iceConnectionState === "failed") || (pc.iceConnectionState === "closed")) {
					this.videoElement.style.opacity = "0.5";
				} else if (pc.iceConnectionState === "new") {
					this.getIceCandidate();
				}
			}
		}
		pc.ondatachannel = function (evt) {
			console.log("remote datachannel created:" + JSON.stringify(evt));

			evt.channel.onopen = function () {
				console.log("remote datachannel open");
				this.send("remote channel openned");
			}
			evt.channel.onmessage = function (event) {
				console.log("remote datachannel recv:" + JSON.stringify(event.data));
			}
		}

		try {
			let dataChannel = pc.createDataChannel("ClientDataChannel");
			dataChannel.onopen = function () {
				console.log("local datachannel open");
				this.send("local channel openned");
			}
			dataChannel.onmessage = function (evt) {
				console.log("local datachannel recv:" + JSON.stringify(evt.data));
			}
		} catch (e) {
			console.log("Cannor create datachannel error: " + e);
		}

		console.log("Created RTCPeerConnnection with config: " + JSON.stringify(this.pcConfig));
		return pc;
	}


	/*
	 * RTCPeerConnection IceCandidate callback
	 */
	WebRtcStreamer.prototype.onIceCandidate = function (event) {
		if (event.candidate) {
			if (this.pc.currentRemoteDescription) {
				this.addIceCandidate(this.pc.peerid, event.candidate);
			} else {
				this.earlyCandidates.push(event.candidate);
			}
		} else {
			console.log("End of candidates.");
		}
	}


	WebRtcStreamer.prototype.addIceCandidate = function (peerid, candidate) {
		fetch(this.srvurl + "/api/addIceCandidate?peerid=" + peerid, {
				method: "POST",
				body: JSON.stringify(candidate)
			})
			.then(this._handleHttpErrors)
			.then((response) => (response.json()))
			.then((response) => {
				console.log("addIceCandidate ok:" + response)
			})
			.catch((error) => this.onError("addIceCandidate " + error))
	}

	/*
	 * RTCPeerConnection AddTrack callback
	 */
	WebRtcStreamer.prototype.onAddStream = function (event) {
		console.log("Remote track added:" + JSON.stringify(event));

		this.videoElement.srcObject = event.stream;
		let promise = this.videoElement.play();
		if (promise !== undefined) {
			promise.catch((error) => {
				console.warn("error:" + error);
				this.videoElement.setAttribute("controls", true);
			});
		}
	}

	/*
	 * AJAX /call callback
	 */
	WebRtcStreamer.prototype.onReceiveCall = function (dataJson) {

		console.log("offer: " + JSON.stringify(dataJson));
		let descr = new RTCSessionDescription(dataJson);
		this.pc.setRemoteDescription(descr).then(() => {
			console.log("setRemoteDescription ok");
			while (this.earlyCandidates.length) {
				let candidate = this.earlyCandidates.shift();
				this.addIceCandidate(this.pc.peerid, candidate);
			}

			this.getIceCandidate()
		}, (error) => {
			console.log("setRemoteDescription error:" + JSON.stringify(error));
		});
	}

	/*
	 * AJAX /getIceCandidate callback
	 */
	WebRtcStreamer.prototype.onReceiveCandidate = function (dataJson) {
		console.log("candidate: " + JSON.stringify(dataJson));
		if (dataJson) {
			for (let i = 0; i < dataJson.length; i++) {
				let candidate = new RTCIceCandidate(dataJson[i]);

				console.log("Adding ICE candidate :" + JSON.stringify(candidate));
				this.pc.addIceCandidate(candidate).then(() => {
					console.log("addIceCandidate OK");
				}, (error) => {
					console.log("addIceCandidate error:" + JSON.stringify(error));
				});
			}
			this.pc.addIceCandidate();
		}
	}


	/*
	 * AJAX callback for Error
	 */
	WebRtcStreamer.prototype.onError = function (status) {
		console.log("onError:" + status);
	}

	return WebRtcStreamer;
})();

if (typeof window !== 'undefined' && typeof window.document !== 'undefined') {
	window.WebRtcStreamer = WebRtcStreamer;
}
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
	module.exports = WebRtcStreamer;
}