What is an Application Server?

Application servers are pivotal in the architecture of modern software applications, serving as a dynamic conduit between the user interface and backend databases. These servers are responsible for executing application logic and enhancing the overall efficiency and management of complex applications. This guide explains what application servers are, their functionality, and their distinct role compared to web servers, providing developers with essential insights into optimizing application performance and security. 

What is an Application Server?

An application server is a software framework that provides an environment for developing, deploying, and running business applications and web services.

Application server plays a crucial role in web application architecture by acting as an intermediary between the front-end user interface and the back-end systems. It enables the execution of business logic, data processing, and communication with external resources.

Understanding web application architecture requires an understanding of how application servers and other components like web servers, databases, and client interfaces work together to deliver seamless web experiences. If you want to know in detail, here is a complete guide on web application architecture.

Why use an Application Server?

In a web-based program, many backend processes are invisible to the end-user but are imperative for the smooth functioning of an application. Let’s take a look at what happens.

Navigating Client Requests through Web Servers and Application Layers

When an application is accessed, the client’s request is sent to the web server. Upon receiving each request, the requirement is to fetch data from the backend database management system. The web server accomplishes this by sending the request to the application server, which resides in the middle layer. Subsequently, the application server takes the request to the DBMS, retrieves the response, and sends it back to the web server. This is how the required action is performed.

Optimal Data Retrieval through Application Server Caching

Every live web-based program needs to perform well when handling multiple client requests, a critical factor for user retention. Throughout this process, fetching data repeatedly from last-tier storage consumes a significant amount of time. In response to this challenge, application servers allow you to cache frequently accessed data. Instead of frequent access to the DBMS, the data is retrieved from RAM. Consequently, the application achieves an optimal minimum response time, leading to improved performance.

Protection of Data and End-User Traffic

A key feature of the application servers that makes them quite important is their ability to secure the data as well as the end-user traffic. This is done because it resides between the web pages and the database. As a result, a direct link between the two is broken. This comes as an advantage as it prevents any cyber-attacks coming in the form of SQL injections. The link is broken and requires business logic to be exposed for validation. This is where any malicious calls can be easily identified. Data is made even more secure as it has the inclusion of authentication to access multiple applications.

How does it work?

Application servers are intermediaries between databases, which store application data, and web clients. They also communicate with web servers, which deliver content to the web client.

Application servers and web servers communicate using servlets, server-side Java classes that process web server requests and return a response. Servlets are used to return dynamic web content to web pages; they process complex requests and transform data from the database. Servlets cost less than Common Gateway Interface (CGI) scripting, another server extension, and they directly connect to the server where CGI does not.

For example, when a web user searches a web application in their browser:

• The user’s request is sent through the web client to the web server (or web application server).
• The web server requests dynamic content from the application server, often using a servlet.
• The application server pulls data from the application database and returns it, along with any dynamic content, to the web server.
• The web server loads the web application for the web client and end user.
• This process differs slightly depending on whether the server is a joint web application server.

In web server architecture, reverse proxy servers and load balancers distribute traffic requests to the servers with available capacity and bandwidth so that user demands can be handled efficiently.

Benefits of using Application Servers

A few benefits of application servers include:

• Instant access to apps: Every application being used is pulled from an application server and delivered by a web server. Web clients make HTTP requests to access a particular app pulled from the application server.
• Traffic optimization: Application servers are designed in such a way that they can handle high incoming traffic for the apps. Application servers are built to handle multiple requests from web clients. In addition, the performance of heavy applications increases by using an application server.
• License management: Installing an application every time on a system is difficult. This is where the application server comes in. Computers can run applications without the need to be run locally. This helps in managing licenses for various applications since only the allowed number of users can use the application at a given time.
• Data integrity: Application servers follow a centralized approach. Any security updates, patches, etc., can be done via the application server. Different users do not need to access the same application and make changes that could cause potential errors.

Types of Application Server

• Active Application Server – This server is used to provide support and a rich environment for business logic that is involved on the server side, which is expressed in the form of rules, components, and objects. These types of servers are also called stateful servers.
• Web Information Server – This type of server is used for generating pages from the database by employing HTML templates. These types of servers are also known as stateless servers.
• Component Server – This software plays a primary role in providing database access to software components. It also provides support to transaction processing requests.

Uses of Application Servers

App servers serve various purposes in web application development and deployment. Some common uses include:

• Handling client requests – process incoming user requests and generate appropriate responses based on the application’s logic and data
• Managing business logic – execute the application’s core logic, facilitating data manipulation and business rules implementation
• Database access – interact with databases to retrieve and update data required by the application
• Session management – maintain user sessions and state information to provide a personalized experience
• Security enforcement – enforce security measures like authentication and authorization to protect sensitive data and resources
• Load balancing – distribute incoming requests among multiple servers to ensure optimal performance and scalability
• Caching – cache frequently accessed data or resources to improve application performance and reduce database load
• Integration with other services – enable communication with external services or APIs, allowing seamless integration with third-party functionalities
• Handling transactions – ensure data integrity and consistency during complex operations
• Web services deployment – They can host web services that enable communication and data exchange between different applications

Conclusion

The use of application servers has increased significantly as more and more applications are being brought to the internet. With each passing day, the importance of data is growing. Considering factors such as response speed for end-users, security, and management convenience, it can be concluded that application servers enable you to thrive in a competitive environment.