util.js¶
util.js
module contais a various helper functions
Analyzing the source code¶
To analyze the source code take the util.js
module version available here
1. Exclude a video codecs from SDP¶
stripCodecs()
code
const stripCodecs = function(sdp, codecs) {
if (!codecs.length) return sdp;
var sdpArray = sdp.split("\n");
var codecsArray = codecs.split(",");
//search and delete codecs line
var pt = [];
var i;
for (var p = 0; p < codecsArray.length; p++) {
console.log("Searching for codec " + codecsArray[p]);
for (i = 0; i < sdpArray.length; i++) {
if (sdpArray[i].search(new RegExp(codecsArray[p],'i')) !== -1 && sdpArray[i].indexOf("a=rtpmap") === 0) {
console.log(codecsArray[p] + " detected");
pt.push(sdpArray[i].match(/[0-9]+/)[0]);
sdpArray[i] = "";
}
}
}
if (pt.length) {
//searching for fmtp
for (p = 0; p < pt.length; p++) {
for (i = 0; i < sdpArray.length; i++) {
if (sdpArray[i].search("a=fmtp:" + pt[p]) !== -1 || sdpArray[i].search("a=rtcp-fb:" + pt[p]) !== -1) {
sdpArray[i] = "";
}
}
}
//delete entries from m= line
for (i = 0; i < sdpArray.length; i++) {
if (sdpArray[i].search("m=audio") !== -1 || sdpArray[i].search("m=video") !== -1) {
var mLineSplitted = sdpArray[i].split(" ");
var newMLine = "";
for (var m = 0; m < mLineSplitted.length; m++) {
if (pt.indexOf(mLineSplitted[m].trim()) === -1 || m <= 2) {
newMLine += mLineSplitted[m];
if (m < mLineSplitted.length - 1) {
newMLine = newMLine + " ";
}
}
}
sdpArray[i] = newMLine;
}
}
}
//normalize sdp after modifications
var result = "";
for (i = 0; i < sdpArray.length; i++) {
if (sdpArray[i] !== "") {
result += sdpArray[i] + "\n";
}
}
return result;
}
2. Exclude all the video codecs from SDP but a certain codec¶
stripVideoCodecsExcept()
code
const stripVideoCodecsExcept = function (sdp, codec) {
let actualStripCodec = "rtx";
if (codec === "VP8") {
actualStripCodec += ",H264";
} else if (codec === "H264") {
actualStripCodec += ",VP8";
} else {
return sdp;
}
return stripCodecs(sdp, actualStripCodec);
}
3. Construct a server websocket URL¶
setURL()
code
const setURL = function () {
var proto;
var url;
var port;
if (window.location.protocol == "http:") {
proto = "ws://";
port = "8080";
} else {
proto = "wss://";
port = "8443";
}
url = proto + window.location.hostname + ":" + port;
return url;
}
4. Get a parameter from URL¶
getUrlParam()
code
const getUrlParam = function (name) {
var url = window.location.href;
name = name.replace(/[\[\]]/g, "\\$&");
var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
results = regex.exec(url);
if (!results) return null;
if (!results[2]) return '';
return decodeURIComponent(results[2].replace(/\+/g, " "));
}
5. Generate an UUID¶
createUUID()
code
const createUUID = function (length) {
var s = [];
var hexDigits = "0123456789abcdef";
for (var i = 0; i < 36; i++) {
s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
}
s[14] = "4";
s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1);
s[8] = s[13] = s[18] = s[23] = "-";
var uuid = s.join("");
return uuid.substring(0, length);
}
6. Browser detection object¶
Browser()
code
const Browser = function() {
const isIE = function () {
return /*@cc_on!@*/false || !!document.documentMode;
}
const isFirefox = function () {
return typeof InstallTrigger !== 'undefined';
}
const isChrome = function () {
return !!window.chrome && /Chrome/.test(navigator.userAgent) && /Google Inc/.test(navigator.vendor) && !/OPR/.test(navigator.userAgent);
}
const isEdge = function () {
return !this.isIE() && !!window.StyleMedia;
}
const isOpera = function () {
return (!!window.opr && !!opr.addons) || !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
}
const isiOS = function () {
return /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
}
const isSafari = function () {
let userAgent = navigator.userAgent.toLowerCase();
return /(safari|applewebkit)/i.test(userAgent) && !userAgent.includes("chrome") && !userAgent.includes("android");
}
const isAndroid = function () {
return navigator.userAgent.toLowerCase().indexOf("android") > -1;
}
const isSafariWebRTC = function () {
return navigator.mediaDevices && this.isSafari();
}
const isSamsungBrowser = function () {
return /SamsungBrowser/i.test(navigator.userAgent);
}
const isAndroidFirefox = function () {
return this.isAndroid() && /Firefox/i.test(navigator.userAgent);
}
const isMobile = function () {
return this.isAndroid() || this.isiOS();
}
return {
isIE: isIE,
isFirefox: isFirefox,
isChrome: isChrome,
isEdge: isEdge,
isOpera: isOpera,
isSafari: isSafari,
isSafariWebRTC: isSafariWebRTC,
isSamsungBrowser: isSamsungBrowser,
isAndroid: isAndroid,
isiOS: isiOS,
isAndroidFirefox: isAndroidFirefox,
isMobile: isMobile
}
}
7. Workaround to play an audio in Safari 12 using a preloader¶
playFirstSound()
code
const playFirstSound = function (parent, preloader) {
return new Promise(function (resolve, reject) {
let audio = document.createElement("audio");
audio.controls = "controls";
audio.muted = true;
audio.hidden = true;
audio.preload = "auto";
audio.type="audio/mpeg";
if (preloader) {
audio.src = preloader;
parent.appendChild(audio);
audio.play().then(function() {
audio.remove();
resolve();
}).catch(function (e) {
console.error("Can't play preloader: " + e);
reject();
});
return;
}
resolve();
});
}
8. Get a short meeting room participant Id¶
getShortUserId()
code