Is it possible to check if the user has a camera and microphone and if the permissions have been granted with Javascript?
Live Demo:
- https://www.webrtc-experiment.com/DetectRTC/
If user didn't allow webcam and/or microphone, then media-devices will be having "NULL" value for the "label" attribute. Above page will show this message: "Please invoke getUserMedia once."
PS. You can type "DetectRTC.MediaDevices" in the Chrome Console developers tool.
Note: It works only in Chrome. Firefox isn't supporting similar API yet. (Updated: Firefox supports as well)
Updated at Dec 16, 2015
Note: Following code snippet works both in Chrome and Firefox.
if (navigator.mediaDevices && navigator.mediaDevices.enumerateDevices) {
// Firefox 38+ seems having support of enumerateDevicesx
navigator.enumerateDevices = function(callback) {
navigator.mediaDevices.enumerateDevices().then(callback);
};
}
var MediaDevices = [];
var isHTTPs = location.protocol === 'https:';
var canEnumerate = false;
if (typeof MediaStreamTrack !== 'undefined' && 'getSources' in MediaStreamTrack) {
canEnumerate = true;
} else if (navigator.mediaDevices && !!navigator.mediaDevices.enumerateDevices) {
canEnumerate = true;
}
var hasMicrophone = false;
var hasSpeakers = false;
var hasWebcam = false;
var isMicrophoneAlreadyCaptured = false;
var isWebcamAlreadyCaptured = false;
function checkDeviceSupport(callback) {
if (!canEnumerate) {
return;
}
if (!navigator.enumerateDevices && window.MediaStreamTrack && window.MediaStreamTrack.getSources) {
navigator.enumerateDevices = window.MediaStreamTrack.getSources.bind(window.MediaStreamTrack);
}
if (!navigator.enumerateDevices && navigator.enumerateDevices) {
navigator.enumerateDevices = navigator.enumerateDevices.bind(navigator);
}
if (!navigator.enumerateDevices) {
if (callback) {
callback();
}
return;
}
MediaDevices = [];
navigator.enumerateDevices(function(devices) {
devices.forEach(function(_device) {
var device = {};
for (var d in _device) {
device[d] = _device[d];
}
if (device.kind === 'audio') {
device.kind = 'audioinput';
}
if (device.kind === 'video') {
device.kind = 'videoinput';
}
var skip;
MediaDevices.forEach(function(d) {
if (d.id === device.id && d.kind === device.kind) {
skip = true;
}
});
if (skip) {
return;
}
if (!device.deviceId) {
device.deviceId = device.id;
}
if (!device.id) {
device.id = device.deviceId;
}
if (!device.label) {
device.label = 'Please invoke getUserMedia once.';
if (!isHTTPs) {
device.label = 'HTTPs is required to get label of this ' + device.kind + ' device.';
}
} else {
if (device.kind === 'videoinput' && !isWebcamAlreadyCaptured) {
isWebcamAlreadyCaptured = true;
}
if (device.kind === 'audioinput' && !isMicrophoneAlreadyCaptured) {
isMicrophoneAlreadyCaptured = true;
}
}
if (device.kind === 'audioinput') {
hasMicrophone = true;
}
if (device.kind === 'audiooutput') {
hasSpeakers = true;
}
if (device.kind === 'videoinput') {
hasWebcam = true;
}
// there is no 'videoouput' in the spec.
MediaDevices.push(device);
});
if (callback) {
callback();
}
});
}
// check for microphone/camera support!
checkDeviceSupport(function() {
document.write('hasWebCam: ', hasWebcam, '<br>');
document.write('hasMicrophone: ', hasMicrophone, '<br>');
document.write('isMicrophoneAlreadyCaptured: ', isMicrophoneAlreadyCaptured, '<br>');
document.write('isWebcamAlreadyCaptured: ', isWebcamAlreadyCaptured, '<br>');
});
Yes it is quite possible to detect whether a microphone and a camera is available after granting the permission,
navigator.getUserMedia({ audio: true, video: true},function (stream) {
if(stream.getVideoTracks().length > 0 && stream.getAudioTracks().length > 0){
//code for when none of the devices are available
}else{
// code for when both devices are available
}
});
1)You should be using Media Recorder and understand promise
2)Check if browser support the API enumerateDevices
if (!navigator.mediaDevices || !navigator.mediaDevices.enumerateDevices) {
console.log("This browser does not support the API yet");
}
let checking=["audioinput","videoinput"];
let onlyHas=[];
navigator.mediaDevices.enumerateDevices()
.then((devices)=> {
let haveAllDevices=true;
devices.forEach((device)=>{
onlyHas.push(device.kind);
if(!(device.kind==checking[0] || device.kind==checking[1])){
haveAllDevices=false;
}
});
//do something about ...
})
.catch(function(err) {
console.log(err.name + ": " + err.message);
});
NotAllowedError
, so for now we are only interested in this error.
If you read DOMException you can see you can acces DOMException.name
, this is the one that you should be compared, so:
let constraints={audio:true,video:true};
navigator.mediaDevices.getUserMedia(constraints)
.then((stream)=>{.....})
.catch((err)=>
{if(err.name=="NotAllowedError"){console.log("User has denied accessed")}
});
PS: About cross browser compatibility MediaRecorder as for today 09/06/2018 it is only supported in chrome and firefox, and the brothers IE and IOS don't https://caniuse.com/#search=MediaRecorder