使用 mongoose 创建 MongoDB 连接

Question

我正在拼命尝试使用 mongoose 创建与 mongoDB 与 MEAN 堆栈的连接。 我的 MongoDB 实例 (mongod) 正在运行，我可以使用 mongo.exe 并通过插入一些文档对其进行测试，它运行良好。但是我在使用 mongoose 创建与 MongoDB 的连接时遇到问题，并且使用 .save() 方法插入文档也不起作用...... 我首先想尝试我的 POST 方法，创建一个函数并通过在 POSTMAN 中创建一些值来测试它。但是我的 MongoDB 数据库中没有插入任何文档..

这是我的 app.js 文件：

var express = require('express');
var app     = express();
var bodyParser = require("body-parser");
var morgan = require("morgan");
//var routes = require('./routes');
//var cors = require('cors')

//configure app
app.use(morgan('dev')); //log requests to the console

//configure body parser
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());

var port = process.env.PORT || 5000;

//DATABASE SETUP
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/DNZ'); //connect to uor datbaase

//Handle the connection event
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));

db.once('open', function() {
console.log("DB connection alive");
});

//DNZ models live here
var FA = require('./models/DNZmodels/FA');

//ROUTES FOR OUR API
//=============================================================================

//create our router
var router = express.Router();

//middleware to use for all requests
router.use(function(req, res, next) {
    // do logging
    console.log('Something is happening.');
    console.log('Today is:', Date())
    next();
});

//test route to make sure everything is working (accessed at GET http://localhost:5000/DNZ/)
router.get('/', function(req, res) {
    res.json({ message: 'Welcome to DNZ API!' });   
});

//on routes that end in /FA
//----------------------------------------------------
router.route('/FA')

    // create a FA (accessed at POST http://localhost:8080/DNZ/FA)
    .post(function(req, res) {
        //console.log(req.body);
        //console.log(req.body.params);
        //res.setHeader('Content-Type', 'application/json')
        res.send(JSON.stringify(req.body));
        /*
        var timestamp = req.body.Timestamp;
        var prognostizierterBetriebswert = req.body.PrognostizierterBetriebswert;
        var posFlexPot = req.body.posFlexPot;
        var negFlexPot = req.body.negFlexPot;
        var leistungsuntergrenze = req.body.Leistungsuntergrenze;
        var leistungsobergrenze = req.body.Leistungsobergrenze;
        var posGesEnergie = req.body.posGesEnergie;
        var negGesEnergie = req.body.negGesEnergie;
        var preissignal = req.body.Preissignal;
        var dummy1 = req.body.Dummy1;
        var dummy2 = req.body.Dummy2;
        var dummy3 = req.body.Dummy3;
    */
        var fa = new FA();
        fa.name = req.body.name;
        console.log("Hier erscheint var fa:", fa);
        //console.log(Dummy1);
        //res.send(JSON.stringify(timestamp));

        // create a new instance of the FA model
        /*
        var fa = new FA({
            Timestamp: timestamp,
            Leistungsuntergrenze: leistungsuntergrenze,
            Leistungsobergrenze:leistungsobergrenze,
            PrognostizierterBetriebswert :prognostizierterBetriebswert,
            posFlexPot: posFlexPot,
            negFlexPot:negFlexPot,  
            posGesEnergie: posGesEnergie,
            negGesEnergie: negGesEnergie,
            Preissignal:preissignal,
            Dummy1: dummy1,
            Dummy2: dummy2,
            Dummy3: dummy3          
        })
        */

        //SAVE the new instance
        fa.save(function(err) {
            if (err) {
                console.log(err);
                res.status(400);
                res.send(err);
        }
        else {
            console.log("debug");
            res.status(200);
            res.json({ message: 'FA created!' });
        }
        });

    })

    // get all the FAs (accessed at GET http://localhost:8080/DNZ/FA)
    .get(function(req, res) {
        FA.find(function(err, fas) {
            if (err)
                res.send(err);

            res.json(fas);
        });
    });

//on routes that end in /FA/:FA_id
//----------------------------------------------------
router.route('/FA/:FA_id')

    // get the bear with that id
    .get(function(req, res) {
        FA.findById(req.params.bear_id, function(err, fa) {
            if (err)
                res.send(err);
            res.json(fa);
        });
    })

    // update the bear with this id
    .put(function(req, res) {
        FA.findById(req.params.FA_id, function(err, fa) {

            if (err)
                res.send(fa);

            //bear.name = req.body.name;
            /*
            FA.save(function(err) {
                if (err)
                    res.send(err);

                res.json({ message: 'FA updated!' });
            });
            */
        });
    })

    /*
    // delete the bear with this id
    .delete(function(req, res) {
        FA.remove({
            _id: req.params.bear_id
        }, function(err, FA) {
            if (err)
                res.send(err);

            res.json({ message: 'Successfully deleted' });
        });
    });
     */

//REGISTER OUR ROUTES -------------------------------
app.use('/DNZ', router);

//START THE SERVER
//=============================================================================
app.listen(port);
console.log('Magic happens on port ' + port);


/*
// set static directories
app.use(express.static('./dist'));
app.use(cors());

// Define Routes
var index = require('./routes/index');
var users = require('./routes/users');

//Set up routes
routes.init(app)

//run
app.listen(port);*/
console.log('Server started, Listening on port ',  port);

我使用了熊教程中的“模板”： https://scotch.io/tutorials/build-a-restful-api-using-node-and-express-4 这里的问题已经是，没有消息：“DB connection alive”。但是，在熊教程（我在这里使用的代码）中，建立了数据库连接，我可以在数据库中插入熊文档。但是，在这里它不起作用...

这是我来自 FA.js 的 FA Schema 模型：

var mongoose = require("mongoose");
var Schema = mongoose.Schema;


var FASchema = new Schema({
    Timestamp: Date,
    PrognostizierterBetriebswert: Number,
    posFlexPot: Number,
    negFlexPot: Number,
    Leistungsuntergrenze: Number,
    Leistungsobergrenze: Number,
    posGesEnergie: Number,
    negGesEnergie: Number,
    Preissignal: Number,
    Dummy1: Schema.Types.Mixed,
    Dummy2: Schema.Types.Mixed,
    Dummy3: Schema.Types.Mixed
    //same: Dummy: {}

});

//var FASchema = new Schema({name: String});

module.exports = mongoose.model("FA", FASchema, 'FA');

console.log("FA wird ausgeführt!");

有人知道为什么没有创建数据库连接吗？

Answer 1

当我测试您的代码时，抛出了错误（发送后无法设置标头）。你可以删除res.send(JSON.stringify(req.body));并重启服务