如何使用 node、express 和 mongoose 制作简单的 RESTful 应用程序

Question

我对服务器端开发完全陌生。几乎整个月我都在学习 mongodb, nodeJs, Express。所以我第一次尝试使用这些来制作简单的 RESTful api。但我一遍又一遍地遇到同样的错误。这是代码：

const http = require("http")
const express = require("express")
const mongoose = require("mongoose");
const bodyParser = require("body-parser");
const schema = mongoose.Schema;
const url = "mongodb:localhost:27017/app";

//connection to db
const con = mongoose.connect(url,{useNewUrlParser:true,useUnifiedTopology:true})
con.then((db)=>{
    console.log("connection is successful");
}).catch((err)=>{
    console.log(err);
});
//schema
const plan = new schema({
    name:{
        type: String,
        required:true,
        unique:true
    },
    gender:{
        type: String,
        required: true
    },
    date:{
        type: Date,
        default: Date.now
    }
})
const details = mongoose.model("model", plan, "details")

const port = 3000;
const hostName = "localhost";
const app = express();

app.use(bodyParser.json());

app.get("/", (req, res)=>{
    res.statusCode = 200;
    res.setHeader("Content-Type","application/json")
    res.end("This is working well")
});

app.post("/details", (req,res)=>{
    details.create(req.body)
    .then((details)=>{
        console.log("new details is added to database")
        res.writeHead(200,{"Content-Type":"application/json"})
        res.json(details)
    })
    .catch((err)=>{
        console.log(err)
    })
})

app.get("/details", (req,res)=>{
    details.find({})
    .then((details)=>{
        res.writeHead(200,{"Content-Type":"application/json"})
        console.log("Recorded documents are: \n")
        res.json(details)
    })
    .catch((err)=>{
        console.log(err)
    })
})

const server = http.createServer(app)
server.listen(port, hostName,()=>{
    console.log(`connected to localhost: ${hostName}:${port}`)

我得到的错误是：

MongoParseError: Invalid connection string
    at parseConnectionString (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongodb\lib\core\uri_parser.js:565:21)
    at connect (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongodb\lib\operations\connect.js:282:3)
    at F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongodb\lib\mongo_client.js:223:5
    at maybePromise (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongodb\lib\utils.js:662:3)
    at MongoClient.connect (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongodb\lib\mongo_client.js:219:10)
    at F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\connection.js:788:12
    at new Promise (<anonymous>)
    at NativeConnection.Connection.openUri (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\connection.js:785:19)
    at F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\index.js:341:10
    at F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\helpers\promiseOrCallback.js:31:5
    at new Promise (<anonymous>)
    at promiseOrCallback (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\helpers\promiseOrCallback.js:30:10)
    at Mongoose.connect (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\node_modules\mongoose\lib\index.js:340:10)
    at Object.<anonymous> (F:\Node.Js files\Coursera\week2\#3 REST API with Express, node and mongoose\#1 Example\index.js:7:22)
    at Module._compile (internal/modules/cjs/loader.js:1176:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1196:10)
connected to localhost: localhost:3000

所以我的问题是，我是不是犯了什么错误？如果是，我该如何解决？

Answer 1

URL应该是：

mongodb://localhost:27017/app

这就是它给您“连接错误”的原因。

如何使用 node、express 和 mongoose 制作简单的 RESTful 应用程序

How to make simple RESTful app using node, express, and mongoose

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