我想了解用户设备是否有连接相机和麦克风,如果有,则使用Javascript获取音视频流之前是否已经授予了权限。我希望至少在Chrome和Firefox上进行此检查。有一个一致的API可以实现这个吗?
我想了解用户设备是否有连接相机和麦克风,如果有,则使用Javascript获取音视频流之前是否已经授予了权限。我希望至少在Chrome和Firefox上进行此检查。有一个一致的API可以实现这个吗?
现场演示:
如果用户没有允许使用网络摄像头和/或麦克风,则媒体设备的“label”属性将具有"NULL"值。上述页面将显示此消息:"请调用getUserMedia一次。"
PS.您可以在Chrome控制台开发者工具中键入"DetectRTC.MediaDevices"。
注意:它仅适用于Chrome。 Firefox尚未支持类似的API。(更新:Firefox也支持)
注意:以下代码片段在Chrome和Firefox中均可正常工作。
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>');
});
navigator.permissions
来检查权限是否已经存在。navigator.permissions.query({ name: "camera" }).then(res => {
if(res.state == "granted"){
// has permission
}
});
但需要注意的是,截至 2021 年 1 月,支持度不够完整:
navigator.permissions.query
,并且至少从 Chrome 87+ 开始支持查询 camera
和 microphone
权限。navigator.permissions.query
,但是截至 Firefox 84,不支持查询 camera
或 microphone
权限。navigator.permissions.query
。在授权后,检测麦克风和摄像头是否可用是完全可能的。
使用旧的API:
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
}
}, function (error) {
// code for when there is an error
});
使用更新的基于 Promise 的 API:
navigator.mediaDevices.getUserMedia({ audio: true, video: true})
.then(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
}
})
.catch(function (error) {
// code for when there is an error
});
1)您应该使用Media Recorder并了解promise。
2)检查浏览器是否支持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.
如果您阅读 DOMException,您将看到可以访问DOMException.name
,这是您应该进行比较的内容,因此:
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: 关于跨浏览器兼容性,截至今天2018年09月06日,MediaRecorder 仅支持 Chrome 和 Firefox 浏览器,而 IE 和 IOS 则不支持。https://caniuse.com/#search=MediaRecorder
该函数检查用户是否具有音频和视频访问权限:
checkMediaAccess = async() => {
navigator.mediaDevices.enumerateDevices().then( devices =>
devices.forEach( device => {
if(device.kind == 'audioinput' && device.label) console.log('Has Audio Access');
if(device.kind == 'videoinput' && device.label) console.log('Has Video Access');
}
));
}
device.label
仅在当前正在流传或已授予权限的情况下才有值,则此代码可能会错误地返回false。 - Alejandro B.<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title></title>
</head>
<body>
<h1>Web camera</h1>
<video autoplay></video>
<script>
function errorMessage(message, e) {
console.error(message, typeof e == 'undefined' ? '' : e);
//alert(message);
}
if (location.protocol === 'https:') {
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
if (navigator.getUserMedia) {
navigator.getUserMedia({ audio: true, video: true }, function (stream) {
document.querySelector('video').src = window.URL.createObjectURL(stream);
var mediaStreamTrack = stream.getVideoTracks()[0];
if (typeof mediaStreamTrack != "undefined") {
mediaStreamTrack.onended = function () {//for Chrome.
errorMessage('Your webcam is busy!')
}
} else errorMessage('Permission denied!');
}, function (e) {
var message;
switch (e.name) {
case 'NotFoundError':
case 'DevicesNotFoundError':
message = 'Please setup your webcam first.';
break;
case 'SourceUnavailableError':
message = 'Your webcam is busy';
break;
case 'PermissionDeniedError':
case 'SecurityError':
message = 'Permission denied!';
break;
default: errorMessage('Reeeejected!', e);
return;
}
errorMessage(message);
});
} else errorMessage('Uncompatible browser!');
} else errorMessage('Use https protocol for open this page.')
</script>
</body>
</html>
if (location.protocol === 'https:' || location.hostname === 'localhost') {
- gimp3695
MediaStreamTrack.getSources
(仅限Chrome)来列出设备,并检查结果是否具有标签。 - xdumaine!navigator.enumerateDevices && navigator.enumerateDevices
?它不是每次都会返回 false 吗? - sertsedat