這是微信wxml的程式碼，構建出一個照相機，並且可以實現前後轉換攝像頭

<!--pages/camera/camera.wxml-->
<!-- <text>pages/camera/camera.wxml</text> -->
 <camera device-position="{{status}}" flash="off" binderror="error" style="width: 100%; height: 300px;"></camera>
 <view class="weui-btn-area">
          <button class="weui-btn" type="primary" bindtap="takePhoto">拍照                   </button>
</view> 
<switch checked  bindchange='switch1Change'/>
 
 

以下是js程式碼，實現轉換攝像頭與訪問介面

// pages/camera/camera.js
Page({

  /**
   * 頁面的初始資料
   */
  data: {
    path:null,
    status:'front'
  },
  switch1Change:function(e){
    if (e.detail.value) {
      this.setData({ status: 'back' })
    } else {
      this.setData({ status: 'front'})
    }
  
  },

  /**
   * 生命週期函式--監聽頁面載入
   */
  onLoad: function (options) {
    this.ctx=wx.createCameraContext()
  },
  takePhoto(){
    this.ctx.takePhoto({
      quality: 'high',
      success: (res) => {
        console.log(res.tempImagePath);
        this.setData({ path: res.tempImagePath})
        wx.uploadFile({
          url: 'login', //僅為示例，非真實的介面地址
          filePath: this.data.path,
          name: 'file',
         
          success: (res)=> {
            // var data = res.data;
            // var msg=JSON.parse(data);
            // console.log(msg);
            wx.showModal({
              title: '提示',
              content: res.data,
            })
          }
        })
      }
    })
  },
  startRecord(){
    this.ctx.startRecord({
      success: (res) => {
        console.log('startRecord')
      }
    })
  },
  stopRecord(){
    this.ctx.stopRecord({
      success: (res) => {
        this.setData({
          src: res.tempThumbPath,
          videoSrc:res.tempVideoPath
        })
      }
    })
  },


  /**
   * 生命週期函式--監聽頁面初次渲染完成
   */
  onReady: function () {
  
  },

  /**
   * 生命週期函式--監聽頁面顯示
   */
  onShow: function () {
  
  },

  /**
   * 生命週期函式--監聽頁面隱藏
   */
  onHide: function () {
  
  },

  /**
   * 生命週期函式--監聽頁面解除安裝
   */
  onUnload: function () {
  
  },

  /**
   * 頁面相關事件處理函式--監聽使用者下拉動作
   */
  onPullDownRefresh: function () {
  
  },

  /**
   * 頁面上拉觸底事件的處理函式
   */
  onReachBottom: function () {
  
  },

  /**
   * 使用者點選右上角分享
   */
  onShareAppMessage: function () {
  
  }
})
 

這是我後臺程式碼，如果不是從微信小程式進入，是訪問不到使用者資料的。

<?php
namespace Home\Controller;
use Think\Controller;
class IndexController extends Controller {
  const HOST='';
  public function _initialize(){
		if(!session('?openid') || !session('?session_key')){
   			die('非法訪問');
   		}
	}
  //初始化人臉
    private function init_face(){
      $APP_ID='';
      $API_KEY='';
      $SECRET_KEY='';
      $dir=APP_PATH.'/facesdk/';
      require_once $dir.'AipFace.php';
      return new \Aipface($APP_ID,$API_KEY,$SECRET_KEY);
    }
   
    public function index($no,$name,$sex,$age){
       $data['no']=$no;
       $data['name']=$name;
       $data['sex']=$sex;
       $data['age']=$age;
       $model = M('rl_students');
       if ($model->where("no='{$no}'")->find()) {
          return $this->ajaxReturn(array('error'=>true,'msg'=>'學號重複！'));
       }else{
       	  $id=$model->add($data);
       	  if($id){
       			return $this->ajaxReturn(array('error'=>false,'id'=>$id));
      		 	}else{
       		return $this->ajaxReturn(array('error'=>true,'msg'=>'添加出錯'));
       		}
       }

     
       
    }
    public function upload($id=''){
    	
      if(empty($id)){
        return false;
      }
      $no=M("rl_students")->where("id={$id}")->getField('no');
      $dir="./Uploads/studentface/";//上傳檔案路徑
      $upload = new \Think\Upload();// 例項化上傳類
      $upload->maxSize = 2048000 ;// 設定附件上傳大小2m
      $upload->exts = array('jpg', 'gif', 'png', 'jpeg');// 設定附件上傳型別
      $upload->rootPath = $dir; // 設定附件上傳根目錄
      //$upload->savePath = ''; // 設定附件上傳（子）目錄
      $upload->saveName=$no;
      $upload->replace=true;
      $upload->autoSub=false;
      // 上傳檔案
      $info = $upload->uploadOne($_FILES['file']);
      if(!$info) {// 上傳錯誤提示錯誤資訊
       return json_encode(array('error'=>true,'msg'=>$upload->getError()),JSON_UNESCAPED_UNICODE);
      }else{// 上傳成功
        $file=$dir.$info['savepath'].$info['savename'];
        $image=base64_encode(file_get_contents($file));
        $this->facevalid($no,$image);
        $m=M('rl_head');
        $data=$m->where("no='{$no}'")->find();
        if($data){
            $m->where("no={$no}")->save(array('base64'=>$image,'path'=>$file));
        }else{
            $m->add(array('no'=>$no,'base64'=>$image,'path'=>$file));
        }
        // return $this->ajaxReturn(array('error'=>false,'msg'=>$info['savepath'].$info['savename'],'id'=>$id));
          echo "採集圖片成功";
           }
    }
  
   public function show($condition=''){
   	   // echo session('openid');
   	   // exit;
   	  //安全認證
   	if(!session('?openid') || !session('?session_key')){
   			die('非法訪問');
   		}
   		
   		$where=array();
   		if(!empty($condition)){
   			$where['s.no|s.name']=$condition;
   		}
   		
   		$data=M('rl_students')
   			->alias('s')
   			->join('rl_head h on s.no=h.no','LEFT')
   			->field('s.id,s.no,s.name,s.sex,s.age,h.path,h.base64')
   			->order('id')
   			->where($where)
   			->page($_GET['page'],6)
   			->select();
   			foreach ($data as  &$row) {
   				$path=$row['path'];
   				if(!empty($path)){
   					if(!file_exists($path)){
   						$dir=dirname($path);
   						mkdir($dir,0777,true);
   						file_put_contents($path, base64_decode($row['base64']));
   					}
   					$row['path']=self::HOST .ltrim($path,'.');
   				}
   				unset($row['base64']);
   			}
   			$this->ajaxReturn($data);
   	
   }
   //獲取小組
    private function face_group(){
      //組名
      $groupname='test';
      $client=$this->init_face();
      $ret=$client->getGroupList();
      if($ret['error_code']==0){
        $grouplist=$ret['result']['group_id_list'];
        if(in_array($groupname, $grouplist)){
          return $groupname;
        }else{
          $ret=$client->groupAdd($groupname);
          if($ret['error_code']==0){
              return $groupname;
          }else{
            return false;
          }
        }
      }else{
        return false;
      }

     }
     //刪除組
    private function del_facegroup(){
        $client=$this->init_face();
        $ret=$client->groupDelete('test');
        print_r($ret);
     }
    //人臉檢測併入庫
    public function facevalid($no,$image){
    
      // $file='./Uploads/2.jpg';
      // if(!file_exists($file)){
      //   die('檔案不存在');
      // }
      // $image=base64_encode(file_get_contents($file));
      //如果有可選引數
      $options=array();
      //$options['face_field']="age";
      $options["max_face_num"]=2;
      // $options["face_type"]="LIVE";
      $client=$this->init_face();
      $ret=$client->detect($image,'BASE64',$options);
      // print_r($ret);
      if($ret['error_code']==0){
        //有人臉
        $result=$ret['result'];
        $face_num=$result['face_num'];
        if(1==$face_num){//人臉數量為1
          $face_probability=$result['face_list'][0]['face_probability'];
          if(1==$face_probability){
            // $guid=myguid();
            $group=$this->face_group();
            // echo $group;
            // exit;
            
            $client->addUser($image,'BASE64',$group,$no);
            echo "人臉檢測完成，並已入庫";
          }else{
            die('可靠性：'.$face_probability);

          }

        }else{
          die('人臉數量大於1');
        }
      }else{
          die('沒有人臉');
          exit;
      }
    }
    public function login(){
      $dir="./Uploads/temp/";//上傳檔案路徑
      if(!file_exists($dir)){
      	mkdir($dir,0777,true);
      }
      $upload = new \Think\Upload();// 例項化上傳類
      $upload->maxSize = 2048000 ;// 設定附件上傳大小2m
      $upload->exts = array('jpg', 'gif', 'png', 'jpeg');// 設定附件上傳型別
      $upload->rootPath = $dir; // 設定附件上傳根目錄
      $upload->savePath='';
      $upload->autoSub=false;
      $info=$upload->uploadOne($_FILES['file']);
      if(!$info){
      		return json_encode(array('error'=>true,'msg'=>$upload->getError()),JSON_UNESCAPED_UNICODE);
      }else{
      	// echo "111";
      	// exit;
      		$file=$dir.$info['savepath'].$info['savename'];
        	$image=base64_encode(file_get_contents($file));
        	// echo $image;
        	// exit;

        	$client=$this->init_face();
        	$options['liveness_control']='NORMAL';
        	$options['max_user_num']=1;
        	$ret=$client->search($image,'BASE64','test',$options);


        	// echo json_encode($ret,JSON_UNESCAPED_UNICODE);
        	// exit;
        	if($ret['error_code']==0){
        		$user=$ret['result']['user_list'][0];
        		$no=$user['user_id'];
        		$score=$user['score'];
        		if(!empty($no)){
        			$data=M('rl_students')->field('no,name,sex')->where("no='{$no}'")->find();
        			
        			// $this->ajaxReturn($data);
              echo json_encode($data,JSON_UNESCAPED_UNICODE);
        		}

        	}
      }
    }

   
}
 

<?php
namespace Home\Controller;
use Think\Controller;
class SessionController extends Controller {
  const HOST='';
  public function session($code){
  		if(empty($code))  return false;
    	$appid="";
    	$secret="";
    	$url="https://api.weixin.qq.com/sns/jscode2session?appid={$appid}&secret={$secret}&js_code={$code}&grant_type=authorization_code";
    	$ret=https_get($url);
    	// echo $ret;
    	// exit;
    	$arr=json_decode($ret,true);
      print_r($arr);
    	if(isset($arr['openid']) && isset($arr['session_key'])){
    		session('openid',$arr['openid']);
    		session('session_key',$arr['session_key']);
    		// $session_id=session_id();
    		// echo $session_id;
    	}else{
    		die($ret);
    	}
  }

 }