What is Middleware?

Middleware is software that connects easily to other software, allowing assorted applications to communicate with each other. In doing so, it lets application developers access a vast range of enhanced functionality without having to write a new integration from scratch.

Middleware can run in almost any location: a local machine, a networked server or over the Cloud. There are many types of middleware, but they all exist to enable developers to build more ambitious solutions with relative ease.

How Does Middleware Work?

One of the most visible examples of this software in everyday life is Single Sign On (SSO). Every internet user has seen SSO on websites that allow them to log in with their Google, Apple or Facebook ID.

When you use SSO to access a site, the site sends a request to the service provider (Google or Apple, for example) asking them to verify. You then get a pop-up asking for your password. If you successfully log in, the SSO provider sends a message back to the website.

This message does not contain your password or any other login details. Instead, it contains a unique identifier and a message to confirm that your login was successful. When the website receives this message, it autocompletes its own login process.

Most middleware isn’t as public-facing as this example. Usually, middleware runs in the background, allowing systems to communicate and share data rapidly. When a developer wants to use an external service, such as a database, they will include a middleware call in their application. This ensures the application and the external service work together with ease.

What are the Main Types of Middleware?

These days, Middleware is an umbrella term used to describe everything from APIs to game engines. One way to better understand the term is to look at the various kinds of existing middleware.

Remote Procedure Call (RPC)

RPC is the original incarnation. When developers use an RPC, it sends a call to a remote machine and asks it to execute a function. For instance, the client system might send a command via RPC to restart a service. The RPC transmits this command to the server, and the server interprets the incoming command and executes the action. RPCs are synchronous, so the client program will pause until the command is complete.

Message-Oriented Middleware (MOM)

MOM followed RPC and introduced an asynchronous approach. In this strategy, the MOM transmits messages back and forth between the server and client systems. The client system doesn’t pause after it issues a message. When it receives a reply, it waits until it is free to process it.

Transactional Middleware

Transactional middleware systems monitor transactions between multiple, disparate services. This lets developers create things like TP monitors, which help coordinate applications when they’re working together. In recent years, developers started using transactional middleware to help monitor web services.

Database-Oriented Middleware

This type connects directly to data sources. This is essential for application development, especially for databases not hosted in the same location as the application. A database middleware controls the flow of data in and out of the database while permitting developers to perform fast queries and updates.

Distributed Objects

When coders moved to an object-oriented model, it became easier for systems to communicate. The distributed objects, or object request broker, permits objects to call each other even when they’re not within the same system. This facilitates a great deal of interoperability, as developers can access functions just by using the target object’s methods.

Application Programming Interface (API)

APIs have become one of the most common forms of middleware in the cloud age. An API is a simple interface that allows external users to run operations. These interfaces create a simple getaway to the underlying service, which developers can access with a simple call. The API publisher has complete control over how users interact with the underlying system. RESTful APIs allow systems to pass a variety of data types between systems, including XML and JSON files.

Why is Middleware Important?

Over time, middleware has evolved into a fundamental part of the global technology structure. Developers now consider it to be the glue that holds most digital technology together. This approach offers multiple advantages, including:

Ease of development: Without this software, developers would be constantly building new integrations every time they want to use an external service. Middleware makes it faster and easier to integrate with other systems. This is good for developers and also good for providers, who want people to use their services.

Standardized integrations: Middleware provides a standard way of linking any application to an external service. This makes it easier for the service provider to anticipate and manage incoming requests. For developers, it means that they can use the other service in any context.

Enhanced security: It provides an additional layer of security for the end service. For example, if an application is directly accessing a database, it could lead to data loss or a security breach. With database middleware, there’s an extra layer that prevents direct access to the database.

Modularization: The middle layer makes it easier to make changes on either side of an integration. Changes on the client are independent of the server, and vice versa. The only time they both need to change is when there is a change to the middleware.

Thanks to the middleware paradigm, developers can build sophisticated applications with relatively little effort. This wouldn’t be possible without the interfaces in the middle.

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Glossary of Terms

A guide to the nomenclature of data integration technology.