如何使用MongoDB开发一个在线聊天系统（mongodb入门

const { MongoClient } = require(mongodb);

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const url = "mongodb://localhost:27017"; zvvq.cn

const dbName = "chat_system"; zvvq

(async function connectMongoDB() { copyright zvvq

try { zvvq.cn

const client = await MongoClient.connect(url); 内容来自zvvq

const db = client.db(dbName); zvvq

console.log(Connected successfully to MongoDB);

// 后续操作放在这里

client.close(); 内容来自zvvq，别采集哟

} catch (err) { 内容来自samhan

console.log(err); zvvq.cn

}

})(); zvvq

const { MongoClient } = require(mongodb); 内容来自samhan

const url = "mongodb://localhost:27017";

const dbName = "chat_system"; 本文来自zvvq

(async function createUser(username, password, avatar) { 内容来自samhan666

try { 内容来自zvvq

const client = await MongoClient.connect(url);

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const db = client.db(dbName);

const user = {

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username,

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password, zvvq.cn

avatar 本文来自zvvq

}; 内容来自samhan

const result = await db.collection(users).insertOne(user);

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console.log(`User ${username} has been created`);

client.close();

} catch (err) { zvvq.cn

console.log(err);

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} 内容来自samhan

})(test, 123456, avatar.png); zvvq.cn

const { MongoClient } = require(mongodb); 内容来自samhan

const url = "mongodb://localhost:27017"; 本文来自zvvq

const dbName = "chat_system";

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(async function sendMessage(senderId, receiverId, content) { copyright zvvq

try {

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const client = await MongoClient.connect(url); 内容来自zvvq

const db = client.db(dbName);

const message = {

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senderId, zvvq.cn

receiverId, zvvq

content,

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createdAt: new Date()

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}; zvvq

const result = await db.collection(messages).insertOne(message); 内容来自zvvq，别采集哟

console.log(Message has been sent); copyright zvvq

client.close(); 内容来自samhan

} catch (err) { zvvq好，好zvvq

console.log(err); 内容来自samhan666

} zvvq好，好zvvq

})(user1, user2, Hello);