Express Framework With NPM

This example illustrates the steps to build a Node.js app with the Express framework, then configuring a Node Package Manager (npm) startup command in one of the configuration files through scripts. This application will be bundled and associated with an AppSail service, and deployed to the console, before you configure the startup command in the console.

1. Create a new folder in your local system for the Express app.

2. Navigate to the directory from your terminal and initialize Node with the following command:

    

        
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         npm init
    

Follow the steps in the terminal and provide the required details.

3. Now, add the express module to your application using the npm package manager by executing the command:

    

        
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         npm install --save express
    

4. You can now add the logic you require in the application’s code in the main file. Given below is a sample code for a basic “Hello World” program.

    

        
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         const express = require('express')
const app = express()
app.all('/', (req, res) => {
    res.status(200).send("Hello World")
})
app.listen(process.env.X_ZOHO_CATALYST_LISTEN_PORT || 9000, () => {
    console.log("Server Started")
})
    

5. Open the package.json configuration file in the application’s directory. Inside the scripts key in the file, you must add a new key: start and configure its value as: node index.js. This defines the startup command for the application. You can then refer to this key while adding the startup command.

6. You can now initialize an AppSail service in the same directory from the CLI or add it in an existing project directory. The app’s source must be your application’s directory. Provide the following value while initializing the app service:

   Stack: Node16

7. Ensure the main file, configuration files, and the node modules are present in the build directory you specify during initialization. Catalyst will automatically ZIP your app files during deployment to the remote console.

8. Deploy the app service to the console.

9. You can then configure the startup command given below from the console:

    

        
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         npm start
    

You can also configure this in the app-config.json file before deploying.

Access the deployed app service from its endpoint URL.