如何在h5页面中调用摄像头来完成拍照之类的操作

/* 
  webpack配置
*/
var path = require('path')
function resolve (pathUrl){
  return path.resolve(__dirname,pathUrl)
}
module.exports = {
  devServer: {
    // 前端端口
    port: 8080,
    // 代理地址
    // proxy: 'http://g5rdyr.ngrok.io'
    proxy: 'http://localhost:8081',
    https: true
  },
}

<template>
  <div id="app">
    <video ref="video" id="video" width="320" height="240" controls></video>
    <canvas id="canvas" ref="canvas" width="320px" height="240px"></canvas>
    <button type="button" class="btn btn-info" @click="camera('environment')">Back Camera</button>
    <button type="button" class="btn btn-info" @click="camera('user')">front Camera</button>
  </div>
</template>

<script>
export default {
  name: 'app',
  data() {
    return {
      video: {},
      localstream: undefined
    }
  },
  mounted() {
    this.$nextTick(()=>{
     this.camera('environment');
    })
  },
  methods: {
    camera (face) {
      this.stop();
      this.gum(face);
    },
    stop () {
      return this.video.srcObject && this.video.srcObject.getTracks().map(t => t.stop());
    },
    gum (face) {
      const fa = face === 'user' ? { facingMode: 'user' } : { facingMode: { exact: 'environment' } };
      return navigator.mediaDevices.getUserMedia({ audio: false, video: fa })
        .then(stream => {
          console.log(stream)
          let video = document.getElementById("video"),
            canvas = document.getElementById("canvas"),
            context = canvas.getContext("2d"),
            vHeight = video.offsetHeight,
            vWidth = video.offsetWidth;
            canvas.width = vWidth; // 改变画布的宽高
            canvas.height = vHeight;
            context.drawImage(video, 0, 0, vWidth, vHeight);
            // 获取图片src  base64格式
            photoSrc = document.getElementById("canvas").toDataURL("image/jpeg", 0.8);
            console.log(photoSrc)
            this.$refs.video.srcObject = stream;
            this.$refs.video.play();
            }).catch(() => {
              navigator.mediaDevices.getUserMedia({ audio: false, video: true })
                .then(stream => {
                  this.$refs.video.srcObject = stream;
                  this.$refs.video.play();
                });
            });
    }
  }
}
</script>