Question

我目前正在构建一个使用mongoskin的node / express.js应用。我最近将我的应用程序部署到了Heroku，并且使用mongohq来处理我的应用程序时遇到了很多麻烦。

这是我用节点app.js

运行的app.js文件

var express = require("express");
var app = express();
decks = require('./routes/decks');
app.get('/decks', decks.findAll);

我的package.json：

{
    "name": "blah blah",
    "description": "Why are there so my blah blah",
    "version": "0.0.1",
    "private": true,
    "dependencies": {
        "express": "3.x",
        "mongodb": "1.1.8",
        "socket.io": "0.9.10"
    },
    "engines": {
        "node": "0.8.4",
        "npm": "1.1.49"
    }
}

阅读Heroku指南后，我尝试重组decks.js并使用像这样的mongoskin。

var mongo = require('mongoskin'); 
var mongoUri = process.env.MONGOHQ_URL;
var db = mongo.db(mongoUri);

exports.findById = function(req, res) {
     var id = req.params.id;
     console.log('Retrieving deck: ' + id);
     db.collection('decks', function(err, collection) {
         collection.findOne({'_id':new BSON.ObjectID(id)}, function(err, item) {
             res.send(item);
         });
     });
 };

但是我一直在收到错误：

 Please ensure that you set the default write concern for the database by setting    =
=   one of the options                                                                 =
=                                                                                      =
=     w: (value of > -1 or the string 'majority'), where < 1 means                     =
=        no write acknowlegement                                                       =
=     journal: true/false, wait for flush to journal before acknowlegement             =
=     fsync: true/false, wait for flush to file system before acknowlegement           =
=                                                                                      =
=  For backward compatibility safe is still supported and                              =
=   allows values of [true | false | {j:true} | {w:n, wtimeout:n} | {fsync:true}]      =
=   the default value is false which means the driver receives does not                =
=   return the information of the success/error of the insert/update/remove            =
=                                                                                      =
=   ex: new Db(new Server('localhost', 27017), {safe:false})                           =
=                                                                                      =
=   http://www.mongodb.org/display/DOCS/getLastError+Command                           =
=                                                                                      =
=  The default of no acknowlegement will change in the very near future                =
=                                                                                      =
=  This message will disappear when the default safe is set on the driver Db           =
========================================================================================

我已经阅读了大量的教程，但我不能让我的数据库工作！如有任何帮助，请您表示赞赏。

Answer 1

您的Db对象使用的是已弃用的设置：“safe”。

如果使用所需的写入关注点设置“w”选项，则该错误应该消失。

这是指向实例化Db对象的文档的链接。

http://mongodb.github.io/node-mongodb-native/api-generated/db.html

...

哦，你可以尝试将你的uri变量更新为process.env.MONGOHQ_URL：P

Answer 2

什么是supershabam所说的是对的

修改此行：

var db = mongo.db(mongoUri);

到此：

var db = mongo.db(mongoUri, {w:1});

这将使您在对数据库执行操作时写入确认，并使错误消失

有关写入问题的详细信息，请查看此link

无法使用Mongoskin和MongoHQ使用Nodejs部署到Heroku

2 个答案: