错误：Mongo + Nodejs项目检测到循环依赖

Question

美好的一天：

我目前正在研究NodeJs + MongoDB项目。我的解决方案很简单，我有3个集合（客户，范围，授权）。范围在“客户与赠款”集合之间形成了多对多关系。目前，我正在查询一个Client记录，然后获取分配给该Client的所有Scope集合，最后，最后获取我先前查询的Scope集合中的所有Grant记录。这是我的代码：

getClient (clientId, clientSecret, callback) {
 let that = this;
 this.mongoClient.collection('client').findOne({"client" : clientId, "client_secret" : clientSecret}, function (err, client) {
     if (err) {
         return callback(err, null);
     } 
     that.mongoClient.collection('scope').find({'client_id': client._id}, {"service_id":1}, function(err, serviceIds) {
         that.mongoClient.collection('grant').find({'_id': { $exists : true, $in : serviceIds }}, function(err, grants) { 
             console.log(grants.toArray());
             callback(err, client);
         })
     });


 });
}

当我运行代码时，我得到的是：

Promise {


 <rejected> Error: cyclic dependency detected
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:296:33)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at serializeObject (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:308:18)
    at serializeInto (/home/vagrant/api/node_modules/bson/lib/bson/parser/serializer.js:776:17)
    at BSON.serialize (/home/vagrant/api/node_modules/bson/lib/bson/bson.js:58:27)
    at Query.toBin (/home/vagrant/api/node_modules/mongodb-core/lib/connection/commands.js:140:25)
    at Pool.write (/home/vagrant/api/node_modules/mongodb-core/lib/connection/pool.js:986:23)
    at Cursor._find (/home/vagrant/api/node_modules/mongodb-core/lib/cursor.js:286:22)
    at nextFunction (/home/vagrant/api/node_modules/mongodb-core/lib/cursor.js:591:10)
    at Cursor.next [as _next] (/home/vagrant/api/node_modules/mongodb-core/lib/cursor.js:699:3)
    at fetchDocs (/home/vagrant/api/node_modules/mongodb/lib/cursor.js:857:10)
    at toArray (/home/vagrant/api/node_modules/mongodb/lib/cursor.js:884:3)
    at /home/vagrant/api/node_modules/mongodb/lib/cursor.js:841:5
    at Promise (<anonymous>)
    at Cursor.toArray (/home/vagrant/api/node_modules/mongodb/lib/cursor.js:840:10)
    at /home/vagrant/api/services/TokenService.js:20:25 }

有趣的一件事是，我发现这是导致问题的代码，但是我迷失了为什么 console.log(grants.toArray());

Answer 1

在猫鼬连接中，将autoIndex设置为false，如下所示：

    mongoose.connect('mongodb://localhost:27017/gscoo', {autoIndex: false});