使用mongoDB和Node.js检测错误循环依赖性

Question

尝试使用MongoDB和Node.js登录用户时出现以下错误。

  

错误：

/opt/lampp/htdocs/FGDP/node_modules/mongodb/lib/mongo_client.js:236
          throw err
          ^

Error: cyclic dependency detected
    at serializeObject (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:296:33)
    at serializeInto (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/opt/lampp/htdocs/FGDP/node_modules/bson/lib/bson/parser/serializer.js:776:17)

我正在解释下面的代码。

  

loginController.js：

var userData={'user_name':$scope.user_name,'user_pass':$scope.user_pass};
        $http({
            method: 'POST',
            url: "/login",
            data: userData,
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' }
        }).then(function successCallback(response){
            console.log('login',response);
            if(response.data['user_type']=='1'){
                $location.path('dashboard');
            }
        },function errorCallback(response) {
            console.log(response);
        });

我的服务器端代码如下所示。

var mongoJs=require('mongojs');
var CryptoJS = require("crypto-js");
var database='FGDP';
var collections=['f_users'];
var db=mongoJs("127.0.0.1:27017/"+database, collections);
exports.userlogin=function(req,res){
    var username=req.body.user_name;
    var password=req.body.user_pass;
    var ciphertext = CryptoJS.AES.encrypt(password, 'lexelPass');
    db.f_users.findOne({login_name:username,password:ciphertext},function(err,docs){
        if(!err){
            if(docs){
                req.session.email=docs.email;
                req.session.name=docs.name;
                req.session.login_name=docs.login_name;
                req.session.status=docs.status;
                req.session.user_type=docs.user_type;
                res.send(docs);
            }
        }
        if(err){
            res.send("Login failed");
        }
    })
}

这里我在服务器端出现上述错误。请帮我解决这个问题。