What is an HTTP Server?
HTTP stands for Hypertext Transfer Protocol, and an HTTP server is a software application that serves web pages and other resources to clients upon request. It acts as a mediator between the client (your web browser) and the server hosting the website.
At its core, an HTTP server’s primary role is to serve web pages to users’ web browsers. When you type a website’s address (URL) into your browser and hit “Enter,” your browser sends a request to the server hosting that website. The HTTP server receives this request and processes it. It identifies the specific web page or resource you’ve requested and locates it within its file system.
Once the requested web page or resource is located, the HTTP server sends it back to your web browser as a response. This response typically includes the HTML, CSS, JavaScript, images, and other files needed to render the web page properly.
HTTP servers aren’t limited to serving static web pages. They can also work with dynamic content. This means that they can process user input, interact with databases, and generate web pages on the fly. This capability is crucial for various web applications, such as online shopping, social media platforms, and email services.
HTTP Protocol
HTTP is the protocol used for this communication. It defines the rules for how data should be structured and transmitted between the server and the browser. This protocol ensures that the data is sent and received correctly, facilitating the seamless display of web pages.
Learn What is HTTP (Hypertext Transfer Protocol)? & What is HTTPS (Hypertext Transfer Protocol Secure)?
How Does HTTP Server Work?
When you type a URL in your browser’s address bar and hit enter, your browser sends an HTTP request to the server hosting the website. This request includes the type of resource you want to access, such as a web page or an image.
The HTTP server receives this request and processes it. It locates the requested resource and sends it back to the client as an HTTP response. The response includes the requested resource and a status code indicating whether the request was successful or encountered an error.
A client-server approach is used by both web and application servers. One program, called the client, asks another program, called the server, for a resource or service.
Hypertext Transfer Protocol (HTTP) is what web servers use to answer calls from people on the World Wide Web. People use HTTP to send and receive data between computers.
Servers can send the site’s HTML file to a user’s web browser, like Google Chrome, through the HTTP request process.
To help you understand better, here’s a summary of the whole process:
- The browser will look for the web server that hosts the site’s files when someone wants to load it.
- With the help of the Domain Name System (DNS), the online browser turns the site’s domain name into an IP address. The web browser will look through its file cache if the site is often viewed.
- Once the browser has found the right web server, it sends an HTTP request to get the site’s information.
- Through its HTTP server, the web server gets the HTTP request and handles it. The HTTP server will look through the database to find the right information once it accepts the request.
- Finally, the server sends the files back to the web browser so that people can access them.
- You will get an HTTP error status code from the server if it can’t find or handle the files you asked for.
Error codes in the HTTP server
A 404 error is the most common type of error message. It means that the page you asked for is not there. A 403 mistake may show up if there are problems with permissions. A 504 error also happens when a web server doesn’t get a response on time from a server that is working as a proxy or gateway.
| HTTP Status Code | Description |
|---|---|
| 200 OK | The request was successful, and the response is valid. |
| 201 Created | The request has been fulfilled, and a new resource has been created. |
| 204 No Content | The request was successful, but there is no response body to send. |
| 400 Bad Request | The server cannot understand the request due to client error or invalid syntax. |
| 401 Unauthorized | Authentication is required, and the provided credentials are invalid. |
| 403 Forbidden | The server understands the request, but it refuses to fulfill it. |
| 404 Not Found | The requested resource could not be found on the server. |
| 500 Internal Server Error | A generic error message indicating a problem on the server’s side. |
| 502 Bad Gateway | The server, acting as a gateway or proxy, received an invalid response from the upstream server. |
| 503 Service Unavailable | The server is currently unable to handle the request due to overload or maintenance. |
These are just a few of the HTTP status codes used to communicate the outcome of an HTTP request between the client (e.g., a web browser) and the server. Each code provides information about the success or failure of the request, and they play a crucial role in troubleshooting issues when interacting with web services.
Uniform Resource Locators (URLs)
HTTP servers use Uniform Resource Locators (URLs) to identify web pages and resources. A URL typically consists of a protocol (HTTP or HTTPS), a domain name (e.g., www.example.com), and a path (e.g., /products/index.html). The server uses this information to locate the requested resource.
Types of HTTP Servers
1. Web Server
A web server is the most fundamental type of HTTP server. It’s designed to serve static web content, such as HTML, CSS, JavaScript, images, and other files. These servers listen for incoming HTTP requests and respond by delivering requested files directly from their file system. Popular web servers include Apache, Nginx, and Microsoft Internet Information Services (IIS).
2. Application Server
Application servers focus on dynamic content and web apps, while web servers handle material that doesn’t change. They can handle requests, talk to systems, and make web pages instantly. Tomcat, Node.js, and Microsoft ASP.NET are all well-known application servers.
3. Proxy Server
Clients and other web servers talk to proxy servers through them. They can do many things, like spreading out the load, saving data, and making things safer. It can send client requests to several backend servers, store and serve cached copies of web content to speed up load times, and screen requests to stop harmful traffic.
4. Caching Server
Caching servers keep copies of web content that is often asked in memory so that origin servers don’t have to work as hard and content can be sent more quickly. To make things run faster, they can be used with web servers and proxy servers. Caching servers are things like Varnish and Squid.
5. Content Delivery Network (CDN)
A content delivery network, or CDN, is a group of proxy servers and data centers carefully placed around the world. CDNs store saved copies of web content and send them to users from a place that is closer to them. This cuts down on latency by a large amount and makes information delivery faster and more reliable. Akamai, CloudFlare, and Amazon CloudFront are all well-known CDNs.
6. Mail Server
It is the job of mail servers, which are also called email servers, to send, receive, and store emails. They mostly use the Simple Mail Transfer Protocol (SMTP) to send emails and either the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) to receive and store emails. However, they can also serve webmail services through HTTP, which lets people check their emails in web browsers.
These are the main kinds of HTTP servers, and each one is used for a different thing when it comes to web communication and data sharing. Which type of server to use relies on the needs and goals of the web service or app that is being hosted.
There are several types of HTTP server software available, including Apache HTTP Server, Nginx, Microsoft IIS, and LiteSpeed. Each server has its own features and capabilities, but they all follow the same basic principles of serving web content.
Use case of HTTP Server
An HTTP server offers various features that make it an essential component of the web. Some of these features include:
- Virtual Hosting: An HTTP server can host multiple websites on a single physical server, allowing efficient use of resources.
- Security: HTTP servers often include security measures such as SSL/TLS encryption to protect sensitive data transmitted between the client and the server.
- Load Balancing: HTTP servers can distribute incoming requests across multiple servers, ensuring optimal performance and preventing overload.
- Logging and Monitoring: HTTP servers keep logs of incoming requests and provide monitoring tools to track server performance and troubleshoot issues.
An HTTP server is a crucial component of the Internet infrastructure. It facilitates the exchange of information between clients and servers, allowing us to access web pages, images, videos, and other resources. Understanding how an HTTP server works helps us appreciate the complexity behind the scenes and the importance of this technology in our daily internet usage.
