What Is Angular Web Server?

What Is Angular Web Server?

Angular Web Server is a powerful tool that allows developers to run and test their Angular applications locally. It provides a simple way to serve your application files, handle HTTP requests, and simulate a production-like environment for development purposes.

Why Do You Need a Web Server for Angular?

When developing an Angular application, you may have noticed that opening the HTML file directly in your browser doesn’t work as expected. This is because Angular applications require a web server to properly handle routing, rendering dynamic content, and fetching data from APIs.

The key reasons why you need a web server for Angular development are:

• Routing: Angular uses client-side routing, which means that navigating through different pages or routes requires the use of a web server. The web server intercepts these requests and serves the appropriate files to render the desired page.
• API Calls: Most Angular applications interact with backend servers or APIs to fetch data.

  A web server allows you to make HTTP requests from your application to external resources without violating cross-origin policies.

• Build Process: In a production environment, an Angular application is usually compiled into optimized JavaScript bundles. A local web server enables you to test this build process locally before deploying it to a live environment.

Angular CLI and the Built-In Development Server

If you are using the Angular Command Line Interface (CLI), you get a built-in development server out of the box. The CLI simplifies many aspects of building an Angular application, including running it locally.

To start the development server using the CLI, navigate to your project’s root directory in the command line and run the following command:

ng serve

This command will start the Angular development server on localhost:4200 by default. You can then access your application by opening a browser and navigating to http://localhost:4200.

Configuring the Angular Web Server

The Angular development server can be configured to meet specific requirements. By default, it serves your application’s files from the src folder. However, if you have custom requirements or need to proxy API requests during development, you can modify the server configuration.

To configure the web server, create a file named proxy.conf.json in your project’s root directory with the following content:

{
  "/api/*": {
    "target": "http://api.example.com",
    "secure": false,
    "logLevel": "debug"
  }
}

In this example, all HTTP requests that start with /api/ will be proxied to http://api.com. The secure property is set to false, allowing non-HTTPS connections for local development. The logLevel property determines the verbosity of logs for debugging purposes.

To start the server with this configuration, use the following command:

ng serve --proxy-config proxy.json

Troubleshooting Common Web Server Issues

If you encounter issues while running your Angular application with a web server, here are some common problems and their solutions:

Error: Port XXXX is already in use

If the default port (4200) is already in use, you can specify a different port by running:

ng serve --port 3000

Error: ENOSPC: System limit for number of file watchers reached

This error occurs when the system’s maximum limit for file watchers is reached. You can increase the limit by running the following command:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

After running this command, restart your development server.

Error: Invalid Host Header

If you see this error, it means that your application’s hostname does not match the expected host header. To fix this, add the –disable-host-check flag when starting the server:

ng serve --disable-host-check

In Conclusion

The Angular Web Server plays a crucial role in developing and testing Angular applications. It allows you to simulate a production environment locally and ensures that your application runs smoothly in various scenarios. By understanding how to configure and troubleshoot common issues with the web server, you can streamline your development workflow and deliver high-quality Angular applications.