如何避免每次服务器刷新时激活 insertMany()？

Question

所以我尝试使用 Mongoose 在数据库中插入数据。每次服务器连接/刷新时，

.insertMany() 

都会运行，从而在数据库中插入相同数据的多个副本。我尝试使用 MongoDB Playground 插入数据，然后使用 Mongoose 获取和发送数据，它确实解决了上述问题，但我只想使用 Mongoose 来插入数据。

服务器.js

const express = require('express');
const mongoose = require('mongoose');
const exchange_route = require('../routes/exchanges')
const data= require('../models/data')

const app = express();
const port = 3000;

async function connect_to_database() {
    try {
        await mongoose.connect('mongodb://localhost:27017/REST-2');
        console.log("Connected to database");
    } catch (error) {
        console.error("Failed to connect to database:", error);
    }
}
connect_to_database(); 
data();

app.get('/', (req, res) => {
    res.send('Hello World');
});

app.use('/exchanges',exchange_route)

app.listen(port, () => {
    console.log(`Server is listening at http://localhost:${port}`);
});

数据.js

const exchanges_2_documents = require('../models/schema')

async function feeding_exchange_2_documents(){
    try {
        await exchanges_2_documents.insertMany(
            [
    {
                  "id": "saucerswap-v2",
                  "name": "Saucerswap V2",
                  "year_established": null,
                  "country": null,
                  "description": "",
                  "url": "https://www.saucerswap.finance/swap",
                  "image": "https://assets.coingecko.com/markets/images/1363/small/SAUCERSWAPv2_1.png?1706865384",
                  "has_trading_incentive": false,
                  "trust_score": 6,
                  "trust_score_rank": 100,
                  "trade_volume_24h_btc": 410.8171966697791,
                  "trade_volume_24h_btc_normalized": 410.8171966697791
                }
 ]
)
 } catch (error) {
        console.log(error.message)
    }
}

module.exports= feeding_exchange_2_documents

Answer 1

看起来您正在尝试实现一个称为“数据库播种”的概念，其中将一组初始文档插入到 MongoDB 集合中。 但是，由于您的

server.js

文件在每次应用程序启动时运行，因此您的

run()

函数也将在每次应用程序启动时运行。这意味着您的

feeding_exchange_2_documents()

函数每次都会插入文档。显然你想避免这种情况。播种通常是在首次启动应用程序或移动环境时在命令行上完成，但您可以采取的一种快速而简单的方法是将

run()

调用移动到路由处理程序中，如下所示：

connect_to_database(); 
//data(); //< Delete it from here

app.get('/', (req, res) => {
    res.send('Hello World');
});

app.get('/seed', async (req, res) => {
   try{
      await data(); //< Add it in here
      res.send('Database Seeded');
   }catch(err){
      res.send('Error when seeding')
   }
});

理想情况下，您想要检查要播种到集合中的文档是否已经存在，这样您就不会继续添加它们，因此只需检查 

"id": "saucerswap-v2"

并在它已经存在时抛出错误，如下所示：

async function feeding_exchange_2_documents(){
    try {
        const doc = await exchanges_2_documents.findOne({id: "saucerswap-v2"});
        if(!doc){ //< doc not found so free to insert
            await exchanges_2_documents.insertMany(
                [
                    {
                        "id": "saucerswap-v2",
                        "name": "Saucerswap V2",
                        "year_established": null,
                        "country": null,
                        "description": "",
                        "url": "https://www.saucerswap.finance/swap",
                        "image": "https://assets.coingecko.com/markets/images/1363/small/SAUCERSWAPv2_1.png?1706865384",
                        "has_trading_incentive": false,
                        "trust_score": 6,
                        "trust_score_rank": 100,
                        "trade_volume_24h_btc": 410.8171966697791,
                        "trade_volume_24h_btc_normalized": 410.8171966697791
                    }
                ]
            )
        }else{
            // Doc was found so throw an error
            throw new Error('Database record already exists')
        }
    } catch (error) {
        console.log(error.message);
        // Remember to throw the error again so that the route handler knows
        throw error;
    }
}