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Express,Sequelize和MySQL的Node.js Rest API示例

本文翻译自Node.js Rest APIs example with Express, Sequelize & MySQL

最新修改:2020年9月29号 bezkoder Node.js

Express是Node.js最受欢迎的Web框架之一,支持路由,中间件,视图系统...Sequelize是基于Promise的Node.js ORM,它支持Postgres,MySQL,SQL Server的方言。在本教程中,我将 向您展示如何使用Express,Sequelize和MySQL数据库来构建Node.js Restful CRUD API。

您应该首先在机器上安装MySQL。 可以在以下位置找到安装说明:
Official MySQL installation manual

相关文章:

全栈:

安全性:Node.js – JWT Authentication & Authorization example
部署:Deploying/Hosting Node.js app on Heroku with MySQL database

Node.js Rest CRUD API概述

我们将构建Rest Apis,它可以创建,检索,更新,删除和按标题查找教程。
首先,我们从Express Web服务器开始。 接下来,我们为MySQL数据库添加配置,使用Sequelize创建Tutorial模型,编写控制器。 然后,我们定义用于处理所有CRUD操作(包括自定义查找程序)的路由。

下表概述了将要导出的Rest API:

Methods Urls Actions
GET api/tutorials get all Tutorials
GET api/tutorials/:id get Tutorial by id
POST api/tutorials add new Tutorial
PUT api/tutorials/:id update Tutorial by id
DELETE api/tutorials/:id remove Tutorial by id
DELETE api/tutorials remove all Tutorials
GET api/tutorials/published find all published Tutorials
GET api/tutorials?title=[kw] find all Tutorials which title contains 'kw'

最后,我们将使用Postman测试Rest Apis。

这是我们的项目结构:
[图片上传失败...(image-5f8879-1604969151628)]

示例视频

这是我们的与MySQL数据库一起运行的Node.js Express Sequelize应用程序演示,并通过Postman测试Rest Apis。

创建Node.js应用

首先,我们创建目录:

$ mkdir nodejs-express-sequelize-mysql
$ cd nodejs-express-sequelize-mysql

接下来,我们使用package.json文件初始化Node.js App:

npm init

name: (nodejs-express-sequelize-mysql) 
version: (1.0.0) 
description: Node.js Rest Apis with Express, Sequelize & MySQL.
entry point: (index.js) server.js
test command: 
git repository: 
keywords: nodejs, express, sequelize, mysql, rest, api
author: bezkoder
license: (ISC)

Is this ok? (yes) yes

我们需要安装必要的模块:expresssequelizemysql2body-parser
运行命令:

npm install express sequelize mysql2 body-parser cors --save

package.json文件应如下所示:

{
  "name": "nodejs-express-sequelize-mysql",
  "version": "1.0.0",
  "description": "Node.js Rest Apis with Express, Sequelize & MySQL",
  "main": "server.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [
    "nodejs",
    "express",
    "rest",
    "api",
    "sequelize",
    "mysql"
  ],
  "author": "bezkoder",
  "license": "ISC",
  "dependencies": {
    "body-parser": "^1.19.0",
    "cors": "^2.8.5",
    "express": "^4.17.1",
    "mysql2": "^2.0.2",
    "sequelize": "^5.21.2"
  }
}

建立Express Web服务器

在根目录下,创建一个新的server.js文件:

const express = require("express");
const bodyParser = require("body-parser");
const cors = require("cors");

const app = express();

var corsOptions = {
  origin: "http://localhost:8081"
};

app.use(cors(corsOptions));

// parse requests of content-type - application/json
app.use(bodyParser.json());

// parse requests of content-type - application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: true }));

// simple route
app.get("/", (req, res) => {
  res.json({ message: "Welcome to bezkoder application." });
});

// set port, listen for requests
const PORT = process.env.PORT || 8080;
app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}.`);
});

我们要做的是:

  • 导入expressbody-parsercors模块:

    • Express用于构建Rest API
    • body-parser有助于解析请求并创建req.body对象
    • cors提供了Express中间件,以使CORS具有多种选择。
  • 创建一个Express应用,然后使用app.use()方法添加body-parsercors中间件。 请注意,我们设置了origin:http:// localhost:8081

  • 定义一个易于测试的GET路由。

  • 在端口8080上侦听传入请求。

现在,使用以下命令运行该应用:node server.js
使用URL http:// localhost:8080/打开浏览器,您将看到:

http://localhost:8080

是的,第一步已经完成。 在下一节中,我们将与Sequelize一起协作。

配置MySQL数据库并进行序列化

在app文件夹中,我们创建一个单独的config文件夹,然后使用db.config.js文件进行配置,如下所示:

module.exports = {
  HOST: "localhost",
  USER: "root",
  PASSWORD: "123456",
  DB: "testdb",
  dialect: "mysql",
  pool: {
    max: 5,
    min: 0,
    acquire: 30000,
    idle: 10000
  }
};

前面5个参数用于MySQL连接。

pool是可选的,它将用于Sequelize连接池配置:

- max:池中的最大连接数
- min:池中的最小连接数
- idle:连接释放之前可以空闲的最长时间(以毫秒为单位)
- acquire:该池将在抛出错误之前尝试获取连接的最长时间(以毫秒为单位)

有关更多详细信息,请访问API Reference for the Sequelize constructor

初始化Sequelize

我们将在下一步包含模型的app/models文件夹中初始化Sequelize。

现在,使用以下代码创建app/models/index.js

const dbConfig = require("../config/db.config.js");

const Sequelize = require("sequelize");
const sequelize = new Sequelize(dbConfig.DB, dbConfig.USER, dbConfig.PASSWORD, {
  host: dbConfig.HOST,
  dialect: dbConfig.dialect,
  operatorsAliases: false,

  pool: {
    max: dbConfig.pool.max,
    min: dbConfig.pool.min,
    acquire: dbConfig.pool.acquire,
    idle: dbConfig.pool.idle
  }
});

const db = {};

db.Sequelize = Sequelize;
db.sequelize = sequelize;

db.tutorials = require("./tutorial.model.js")(sequelize, Sequelize);

module.exports = db;

不要忘记在server.js中调用sync()方法

...
const app = express();
app.use(...);

const db = require("./app/models");
db.sequelize.sync();

...

在开发中,您可能需要删除现有表并重新同步数据库。 只需使用force:true即可,如下代码:

db.sequelize.sync({ force: true }).then(() => {
  console.log("Drop and re-sync db.");
});

定义Sequelize模型

在models文件夹中,像这样创建tutorial.model.js文件:

module.exports = (sequelize, Sequelize) => {
  const Tutorial = sequelize.define("tutorial", {
    title: {
      type: Sequelize.STRING
    },
    description: {
      type: Sequelize.STRING
    },
    published: {
      type: Sequelize.BOOLEAN
    }
  });

  return Tutorial;
};

该Sequelize模型表示MySQL数据库中的tutorials表。 这些列将自动生成:id, title, description, published, createdAt, updatedAt.

初始化Sequelize之后,我们无需编写CRUD函数,Sequelize支持所有这些功能:

  • 创建一个新的教程:create(object)
  • 通过id查找教程:findByPk(id)
  • 获取所有教程:findAll()
  • 通过id:update(data, where: { id: id })
  • 删除教程:destroy(where: { id: id })
  • 删除所有教程:destroy(where:{})
  • 按标题查找所有教程:findAll({ where: { title: ... } })

这些功能将在我们的控制器中使用。

我们可以通过为每个教程添加评论来改进示例。 这是一对多关系,我为此编写了一个教程:
Sequelize Associations: One-to-Many example – Node.js, MySQL

或者,您可以为每个教程添加标签,并将教程添加到标签(多对多关系):
Sequelize Many-to-Many Association example with Node.js & MySQL

创建控制器

app/controllers文件夹中,让我们使用以下CRUD函数创建tutorial.controller.js:

  • create
  • findAll
  • findOne
  • update
  • delete
  • deleteAll
  • findAllPublised
const db = require("../models");
const Tutorial = db.tutorials;
const Op = db.Sequelize.Op;

// Create and Save a new Tutorial
exports.create = (req, res) => {
  
};

// Retrieve all Tutorials from the database.
exports.findAll = (req, res) => {
  
};

// Find a single Tutorial with an id
exports.findOne = (req, res) => {
  
};

// Update a Tutorial by the id in the request
exports.update = (req, res) => {
  
};

// Delete a Tutorial with the specified id in the request
exports.delete = (req, res) => {
  
};

// Delete all Tutorials from the database.
exports.deleteAll = (req, res) => {
  
};

// Find all published Tutorials
exports.findAllPublished = (req, res) => {
  
};

让我们实现这些功能。

创建一个新对象

创建并保存一个新教程:

exports.create = (req, res) => {
  // Validate request
  if (!req.body.title) {
    res.status(400).send({
      message: "Content can not be empty!"
    });
    return;
  }

  // Create a Tutorial
  const tutorial = {
    title: req.body.title,
    description: req.body.description,
    published: req.body.published ? req.body.published : false
  };

  // Save Tutorial in the database
  Tutorial.create(tutorial)
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while creating the Tutorial."
      });
    });
};

检索对象(有条件)

从数据库中检索所有教程/按标题查找:

exports.findAll = (req, res) => {
  const title = req.query.title;
  var condition = title ? { title: { [Op.like]: `%${title}%` } } : null;

  Tutorial.findAll({ where: condition })
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while retrieving tutorials."
      });
    });
};

我们使用req.query.title从Request中获取查询字符串,并将其作为findAll()方法的条件。

检索单个对象

查找具有ID的单个教程:

exports.findOne = (req, res) => {
  const id = req.params.id;

  Tutorial.findByPk(id)
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message: "Error retrieving Tutorial with id=" + id
      });
    });
};

更新对象

更新由请求中的id标识的教程:

exports.update = (req, res) => {
  const id = req.params.id;

  Tutorial.update(req.body, {
    where: { id: id }
  })
    .then(num => {
      if (num == 1) {
        res.send({
          message: "Tutorial was updated successfully."
        });
      } else {
        res.send({
          message: `Cannot update Tutorial with id=${id}. Maybe Tutorial was not found or req.body is empty!`
        });
      }
    })
    .catch(err => {
      res.status(500).send({
        message: "Error updating Tutorial with id=" + id
      });
    });
};

删除对象

删除具有指定id的教程:

exports.delete = (req, res) => {
  const id = req.params.id;

  Tutorial.destroy({
    where: { id: id }
  })
    .then(num => {
      if (num == 1) {
        res.send({
          message: "Tutorial was deleted successfully!"
        });
      } else {
        res.send({
          message: `Cannot delete Tutorial with id=${id}. Maybe Tutorial was not found!`
        });
      }
    })
    .catch(err => {
      res.status(500).send({
        message: "Could not delete Tutorial with id=" + id
      });
    });
};

删除所有对象

从数据库中删除所有教程:

exports.deleteAll = (req, res) => {
  Tutorial.destroy({
    where: {},
    truncate: false
  })
    .then(nums => {
      res.send({ message: `${nums} Tutorials were deleted successfully!` });
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while removing all tutorials."
      });
    });
};

按条件查找所有对象

查找所有published = true的教程:

exports.findAllPublished = (req, res) => {
  Tutorial.findAll({ where: { published: true } })
    .then(data => {
      res.send(data);
    })
    .catch(err => {
      res.status(500).send({
        message:
          err.message || "Some error occurred while retrieving tutorials."
      });
    });
};

可以对该控制器进行一些修改以返回分页响应:

{
    "totalItems": 8,
    "tutorials": [...],
    "totalPages": 3,
    "currentPage": 1
}

您可以在以下位置找到更多详细信息:
Server side Pagination in Node.js with Sequelize and MySQL

定义路由

当客户端使用HTTP请求(GET,POST,PUT,DELETE)发送对端点的请求时,我们需要通过设置路由来确定服务器的响应方式。

这些是我们的路由:

  • /api/tutorials:GET,POST,DELETE
  • /api/tutorials/:id:GET,PUT,DELETE
  • /api/tutorials/published:GET
    app/routes文件夹中创建一个turorial.routes.js,其内容如下:
module.exports = app => {
  const tutorials = require("../controllers/tutorial.controller.js");

  var router = require("express").Router();

  // Create a new Tutorial
  router.post("/", tutorials.create);

  // Retrieve all Tutorials
  router.get("/", tutorials.findAll);

  // Retrieve all published Tutorials
  router.get("/published", tutorials.findAllPublished);

  // Retrieve a single Tutorial with id
  router.get("/:id", tutorials.findOne);

  // Update a Tutorial with id
  router.put("/:id", tutorials.update);

  // Delete a Tutorial with id
  router.delete("/:id", tutorials.delete);

  // Delete all Tutorials
  router.delete("/", tutorials.deleteAll);

  app.use('/api/tutorials', router);
};

您可以看到我们使用了/controllers/tutorial.controller.js中的控制器。

我们还需要在server.js中包含路由(在app.listen()之前):

...

require("./app/routes/turorial.routes")(app);

// set port, listen for requests
const PORT = ...;
app.listen(...);

测试API

使用以下命令运行我们的Node.js应用程序:node server.js
控制台显示:

Server is running on port 8080.
Executing (default): DROP TABLE IF EXISTS `tutorials`;
Executing (default): CREATE TABLE IF NOT EXISTS `tutorials` (`id` INTEGER NOT NULL auto_increment , `title` VARCHAR(255), `description` VARCHAR(255), `published` TINYINT(1), `createdAt` DATETIME NOT NULL, `updatedAt` DATETIME NOT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB;
Executing (default): SHOW INDEX FROM `tutorials`
Drop and re-sync db.

使用Postman,我们将测试以上所有的Apis。

1、使用POST/tutorials Api创建一个新教程

Create a new Tutorial

创建一些新教程后,您可以检查MySQL表:

mysql> select * from tutorials;
+----+-------------------+-------------------+-----------+---------------------+---------------------+
| id | title             | description       | published | createdAt           | updatedAt           |
+----+-------------------+-------------------+-----------+---------------------+---------------------+
|  1 | JS: Node Tut #1   | Tut#1 Description |         0 | 2019-12-13 01:13:57 | 2019-12-13 01:13:57 |
|  2 | JS: Node Tut #2   | Tut#2 Description |         0 | 2019-12-13 01:16:08 | 2019-12-13 01:16:08 |
|  3 | JS: Vue Tut #3    | Tut#3 Description |         0 | 2019-12-13 01:16:24 | 2019-12-13 01:16:24 |
|  4 | Vue Tut #4        | Tut#4 Description |         0 | 2019-12-13 01:16:48 | 2019-12-13 01:16:48 |
|  5 | Node & Vue Tut #5 | Tut#5 Description |         0 | 2019-12-13 01:16:58 | 2019-12-13 01:16:58 |
+----+-------------------+-------------------+-----------+---------------------+---------------------+

2、使用GET /tutorials Api检索所有的教程

Retrieve all Tutorials

3、使用GET /tutorials/:id Api根据id查询单个教程
Retrieve a single Tutorial by id

4、使用`PUT /tutorials/:id' Api更新教程
Update a Tutorial

在更新某些行后,请查看tutorials表:

mysql> select * from tutorials;
+----+-------------------+-------------------+-----------+---------------------+---------------------+
| id | title             | description       | published | createdAt           | updatedAt           |
+----+-------------------+-------------------+-----------+---------------------+---------------------+
|  1 | JS: Node Tut #1   | Tut#1 Description |         0 | 2019-12-13 01:13:57 | 2019-12-13 01:13:57 |
|  2 | JS: Node Tut #2   | Tut#2 Description |         0 | 2019-12-13 01:16:08 | 2019-12-13 01:16:08 |
|  3 | JS: Vue Tut #3    | Tut#3 Description |         1 | 2019-12-13 01:16:24 | 2019-12-13 01:22:51 |
|  4 | Vue Tut #4        | Tut#4 Description |         1 | 2019-12-13 01:16:48 | 2019-12-13 01:25:28 |
|  5 | Node & Vue Tut #5 | Tut#5 Description |         1 | 2019-12-13 01:16:58 | 2019-12-13 01:25:30 |
+----+-------------------+-------------------+-----------+---------------------+---------------------+

5、使用GET /tutorials?title=node查找标题包含'node'的所有教程

Find all Tutorials which title contains ‘node’

6、使用GET /tutorials/published Api查询所有已发布的教程
Find all published Tutorials

7、使用'DELETE /tutorials/:idApi删除一个教程 ![Delete a Tutorial](https://upload-images.jianshu.io/upload_images/15949040-921d6d926ec1ec72?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240) id = 2的教程已从tutorials`表中删除:

mysql> select * from tutorials;
+----+-------------------+-------------------+-----------+---------------------+---------------------+
| id | title             | description       | published | createdAt           | updatedAt           |
+----+-------------------+-------------------+-----------+---------------------+---------------------+
|  1 | JS: Node Tut #1   | Tut#1 Description |         0 | 2019-12-13 01:13:57 | 2019-12-13 01:13:57 |
|  3 | JS: Vue Tut #3    | Tut#3 Description |         1 | 2019-12-13 01:16:24 | 2019-12-13 01:22:51 |
|  4 | Vue Tut #4        | Tut#4 Description |         1 | 2019-12-13 01:16:48 | 2019-12-13 01:25:28 |
|  5 | Node & Vue Tut #5 | Tut#5 Description |         1 | 2019-12-13 01:16:58 | 2019-12-13 01:25:30 |
+----+-------------------+-------------------+-----------+---------------------+---------------------+

8、使用'DELETE /tutorialsApi删除所有的教程 ![Delete all Tutorials](https://upload-images.jianshu.io/upload_images/15949040-e3fc6ce85574b9bc?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240) 现在在tutorials`表中没有一行数据了:

mysql> SELECT * FROM tutorials;
Empty set (0.00 sec)

结论

今天,我们已经学习了如何使用Express Web服务器创建Node.js Rest Apis。 我们还知道添加MySQL数据库和Sequelize配置,创建Sequelize模型,编写控制器以及定义用于处理所有CRUD操作的路由的方法。

您可以在下一个教程中找到更多有趣的东西:

{
    "totalItems": 8,
    "tutorials": [...],
    "totalPages": 3,
    "currentPage": 1
}

学习愉快! 再见。

进一步阅读

将教程数据从文件上传到MySQL数据库表:
- Node.js: Upload Excel file data into MySQL Database
- Node.js: Upload CSV file data into MySQL Database

源代码

您可以在Github上找到此示例的完整源代码。

如果要为每个教程添加评论。 它是一对多关联,有一个有关该关系的教程:Sequelize Associations: One-to-Many example – Node.js, MySQL

或者,您可以为每个教程添加标签,并将教程添加到标签(多对多关系):
Sequelize Many-to-Many Association example with Node.js & MySQL

作者:雪域迷影

原文链接:https://www.jianshu.com/p/a1ab69e193a8

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