Node js get 什么也得不到

Question

所以我目前正在学习如何用Node Js和MongoDB构建一个Rest API，所以很自然地我一直在遵循一些教程，当时间到来时，我已经设置了一个示例，但它不起作用。

我有 2 个主要文件，应用程序.js和历史.js(模型(。

在应用程序上.js我有以下内容：

const express = require('express');
const app = express();
const bodyParser = require('body-parser');
const mongoose = require('mongoose');
app.use(bodyParser.json());
Historic =require('./models/historic');
// Connect to Mongoose
mongoose.connect('mongodb://localhost/test', { useMongoClient: true });
var db = mongoose.connection;
console.log('Here');
db.on('error', function(err){
  if(err){
    console.log(err);
    throw err;
  } 
});
db.once('open', function callback () {
  console.log('Mongo db connected successfully');
});
app.get('/', (req, res) => {
    res.send('Please use /api/historic');
});

app.get('/api/historics', (req, res) => {
    Historic.getHistorics((err, historic) => {
        if(err){
            throw err;
        }
        res.json(historic);
    });
});
app.listen(27017);
console.log('Running on port 27017...');

然后在我的模型上，我有以下内容：

const mongoose = require('mongoose');
// Historic Schema
const historicSchema = mongoose.Schema({
    _id:{
        type: String,
        required: true
    },
    url:{
        type: String,
        required: true
    },
    price:{
        type: String,
        required: true
    },
    timestamp:{
        type: String,
        required: true
    }
});
const Historic = module.exports = mongoose.model('Historic', historicSchema);
// Get Historics
module.exports.getHistorics = (callback, limit) => {
    console.log('Get Historics-Historic');
    Historic.find(callback).limit(limit);
    console.log('Get Historics-Historic-After find');
    console.log(limit);
}

每当我尝试访问 http://localhost:27017/api/historics/时，我只会得到：[]。

我知道我的数据库上有数据，如您在图像上看到的那样：数据库测试数据

有什么提示吗？

Answer 1

根据 Docs http://mongoosejs.com/docs/2.7.x/docs/finding-documents.html，回调至少应该是 .find 方法的第二个参数。尝试替换

    // Get Historics
module.exports.getHistorics = (callback, limit) => {
    console.log('Get Historics-Historic');
    Historic.find(callback).limit(limit);
    console.log('Get Historics-Historic-After find');
    console.log(limit);
}

自

// Get Historics
module.exports.getHistorics = (callback, limit) => {
var query = Historic.find({});
query.limit(limit);
query.exec(callback);
}

Answer 2

我被告知解决方案并且它有效。

旧代码：

const historicSchema = mongoose.Schema({
    _id:{
        type: String,
        required: true
    },
    url:{
        type: String,
        required: true
    },
    price:{
        type: String,
        required: true
    },
    timestamp:{
        type: String,
        required: true
    }
});

溶液：

const historicSchema = mongoose.Schema({
    _id:{
        type: String,
        required: true
    },
    url:{
        type: String,
        required: true
    },
    price:{
        type: String,
        required: true
    },
    timestamp:{
        type: String,
        required: true
    }
}, {collection: 'historic'});

我需要添加在猫鼬上定义的集合名称