"Argument必须是一个字符串",其中包含Node.js中的某些MongoDB ObjectID

Question

我在Node中遇到这样的错误:

TypeError: Argument must be a string
    at TypeError (native)
    at Buffer.write (buffer.js:791:21)
    at serializeObjectId
    <snip>

条件是在使用MongoDB执行查找操作时ObjectID的一些用法.ObjectID的一些用法引发了这个错误,有些则没有.唯一重要的是ObjectID的来源.如果它是从现有的集合中提取的,那就有效了.如果我自己生成它(例如,使用ObjectID.createFromHexString),它就会失败,如上所述.

Answer 1

我花了几个小时才找到这个。问题归结于我对 Mongoose 的使用。我对我的一些集合使用了 Mongoose 模式，而对其他集合则没有使用 Mongoose。这是包含我有问题的代码的文件：

// Some common MongoDb operations and data.

'use strict';

var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var logger = require('./Logger');

var mongoose = require('mongoose');
// TODO: Take this out for production.
mongoose.set('debug, true');

var PSSharingInvitations = require('./PSSharingInvitations')

var connectedDb = null;

// Call this just once, at the start of the server.
// TODO: Need better error handling when can't initially connect. Right now have an ugly looking error when Mongo is not already started and we try to start our server.
exports.connect = function(mongoDbURL) {
    MongoClient.connect(mongoDbURL, function(err, db) {
        assert.equal(null, err);
        if (!db) {
            logger.error("**** ERROR ****: Cannot connect to MongoDb database!");
        }
        else {
            mongoose.connect(mongoDbURL);
            var db = mongoose.connection;
            db.on('error', console.error.bind(console, 'connection error:'));
            db.once('open', function() {
                // SCHEMA's
                exports.SharingInvitation = PSSharingInvitations.buildSchema(mongoose);

                logger.info("Mongoose: Connected to MongoDb database");
            });

            connectedDb = db;
            logger.info("Mongo: Connected to MongoDb database");
        }
    });
};

exports.db = function () {
    return connectedDb;
};

// Call this just once, when the server shuts down.
exports.disconnect = function() {
};

问题原来出在这一行：

connectedDb = db;

其中 db 是mongoose.connection. 也就是说，我使用mongoose.connectionMongoDB Collections 作为我的数据库，但未使用 Mongoose。这导致了间歇性错误。

修改后的（到目前为止有效！）代码如下：

exports.connect = function(mongoDbURL) {
    MongoClient.connect(mongoDbURL, function(err, db) {
        assert.equal(null, err);
        if (!db) {
            logger.error("**** ERROR ****: Cannot connect to MongoDb database!");
        }
        else {
            connectedDb = db;
            logger.info("Mongo: Connected to MongoDb database");

            mongoose.connect(mongoDbURL);
            var connectedMongooseDb = mongoose.connection;
            connectedMongooseDb.on('error', console.error.bind(console, 'connection error:'));
            connectedMongooseDb.once('open', function() {

                // SCHEMA's
                exports.SharingInvitation = PSSharingInvitations.buildSchema(mongoose);

                logger.info("Mongoose: Connected to MongoDb database");
            });
        }
    });
};