How to use nodejs+egg

Node.js has become a quite popular technology option in the development of today's web applications. It allows developers to write server-side code using JavaScript and can handle highly concurrent, real-time, data-intensive applications.

Egg.js is a fast, flexible and scalable web development framework based on Node.js. It is commonly used to build enterprise-level web applications. Egg.js provides many functions such as routing, middleware, plug-ins, and front-end rendering.

In this article, we will explain in detail how to build a web application using Node.js and Egg.js.

1. Install Node.js and Egg.js

Before we begin, we need to install Node.js and Egg.js. You can download the installation package from the official website, or install it using Node.js's package manager npm.

Egg.js depends on the Node.js running environment, so you need to ensure that Node.js has been installed correctly.

To install Egg.js, just run the following command in a terminal window:

npm install egg --save

2. Create Egg.js Application

After installing Egg.js, we can use the following command to create a new Egg.js application:

npx egg-init my-egg-app --type=simple

This command will create a new Egg.js application where my-egg -app is your application name, --type=simple means we are creating a simple Egg.js application.

3. Configuring the Egg.js Application

After creating the Egg.js application, we need to configure the application to ensure it runs correctly.

Configuration fileconfig/config.default.js is the default configuration file for the Egg.js application. We can change the default behavior of the application by modifying the configuration.

For example, the port number for the application to run can be set in the configuration file. We can change it to 3000, which is a common HTTP application port number:

// config/config.default.js
exports.keys = 'my_secret_key';

exports.cluster = {
  listen: {
    port: 3000,
  }
};

Additionally, we can also use plugins in the configuration file to add some functionality. For example, if we need to forward requests to other services, we can add a proxy plugin egg-http-proxy.

Here is the sample code of how to add the egg-http-proxy plugin:

// config/plugin.js
exports.httpProxy = {
  enable: true,
  package: 'egg-http-proxy',
};

Then in the configuration file config/config.default.js Use the httpProxy plug-in and set it up:

// config/config.default.js
exports.httpProxy = {
  '/api': {
    target: 'http://127.0.0.1:7001',
    changeOrigin: true,
    rewrite: (path) => path.replace(/^/api/, ''),
  },
};

This configuration code forwards all requests starting with /api to the service with local port number 7001. At the same time, the changeOrigin option will replace the host header in the HTTP request with the host name in the target URL, and the rewrite option will rewrite the request path to URLs that do not contain the /api prefix.

4. Writing controllers and routing

The MVC framework of Egg.js includes controllers, models and views. We can handle HTTP requests by writing controllers and routes and return response results.

The controller is located in the app/controller directory. We can create a new controller to handle HTTP requests. For example, we can create a controller named home.js and define a index method in it:

// app/controller/home.js
const Controller = require('egg').Controller;

class HomeController extends Controller {
  async index() {
    const { ctx } = this;
    ctx.body = 'Hello World';
  }
}

module.exports = HomeController;

Now we need to add A route. We can define routes in the app/router.js file:

// app/router.js
module.exports = (app) => {
  const { router, controller } = app;
  router.get('/', controller.home.index);
};

Here we define a route for the root URL path and connect it with HomeController The index method is bound.

5. Run the Egg.js application

Finally, we can use the following command to start the Egg.js application:

npm start

This command will start Egg.js application and listens for requests from clients.

6. Conclusion

In this article, we have learned how to build a web application using Node.js and Egg.js. We learned how to install Node.js and Egg.js, create an Egg.js application, configure an Egg.js application, write controllers and routes, and run an Egg.js application.

Egg.js is a powerful web development framework that provides many features to help developers build efficient, scalable, and easy-to-maintain web applications. If you are looking for a reliable and powerful Node.js framework, Egg.js might be a good choice.

The above is the detailed content of How to use nodejs+egg. For more information, please follow other related articles on the PHP Chinese website!