Middleware: definition and applications

Middleware is a kind translation interface between an operating system and running applications. It allows the exchange and management of data between applications and operating systems that are not compatible with each other.

What is middleware?¶

Middleware is software that works invisibly in the background. It is an application that makes the link between the operating system and the programs that run on it. Also called “middleware”, they work like hidden translators and enable communication and management of applications. Middleware connects two applications together and facilitates data exchange. Internet users can thus accomplish everyday tasks as mundane as submitting forms on a Web page or calculating results adapted to their profile from dynamic Web pages. We can consider middleware as exchange tools between two languages.

Middleware development¶

During the 2000s and until 2010, middleware took the form of application server. With the help of technology, with the growing popularity of Cloud Computing and the replacement of monolithic systems by microservices architectures, middleware has evolved.

Instead of deploying complete applications on middleware servers, developers have tended to create smaller microservices-like applications. These microservices are then equipped with all the necessary functions in order to connect to the required back-end resources and deploy the applications in a system that supports containers like Docker.

The Docker container is then made available in a cloud-based service. The middleware then works as a combination of the container-hosted microservice and the cloud computing infrastructure it runs on. This allows to consume fewer resources compared to a traditional server or a virtual machine.

Where does the name middleware come from?¶

The word « middleware » of English origin can be translated by « intermediate software », or the French term intergiciel. It is a layer of services (software) located between the user-side inputs in the front-end and the queries or calculations in progress in the back-end. Most of the time, customer (user) interactions with software are done through a front-end application. Resources such as databases, file servers, NoSQL data warehouses, and message queues are often found on the back end. The middleware sits halfway between these two ends.

Characteristics of middleware¶

To be considered middleware, a program must verify certain characteristics and support a number of functions, including:

• Be independent of the existing hardware and the operating system used;
• Be independent of the specific network design and protocols used;
• Be independent of a programming language;
• Run in the background invisibly.

Types of middleware¶

There are many examples of middleware, each developed for different applications in web and cloud services. These middleware can be divided into three different areas of application distributed as follows:

Middleware for communication¶

This type of software is intended to put on the same plane different types of networks and to enable communication with each other. These applications are found in web services where the HTTP protocol allows two computers to connect to the Internet independent of the operating system.

Middleware for sending messages¶

This type of middleware is used when two different applications wish to exchange messages. The middleware in question determines the form these messages will take. Affected applications are able to send and receive information through this format. If they do not go through the very popular JSON (JavaScript Object Notation), web services use this format.

Middleware for applications¶

Middleware can also be programming languages ​​or operating systems designed to run regardless of platforms. One can quote for example the programming language .NET which makes it possible to program applications for several operating systems. API middleware provides developers with tools to create, reveal, and manage APIs for their applications so that other developers can use them. Middleware by RPC (for Remote Procedure Call) allows an application to trigger a procedure in another application. This procedure can be done on the same computer, on another computer or on the network using an RPC.

How does middleware work?

At the simplest level, middleware allows developers to build applications without having to provide dedicated integration each time they connect to application components, data sources, computing resources, or devices. This is done by providing services that allow communication through the most common frameworks. Among them, we can mention JSON (JavaScript Object Notation), REST (Representational State Transfer), XML (Extensible Markup Language), SOAP (Simple Object Access Protocol) or Webservices.

In general, middleware also provides services that enable the communication between components written in different languages ​​like Java, C++, PHP, Python.

Fields of application of middleware¶

Unknowingly, most people perform many daily tasks using middleware. Here are the most common fields of application:

Communication between browsers¶

Applications in Internet browsers are most often managed by middleware: form filling contact or subscription to a newsletter are among the most common applications. Regardless of browser or operating system input, the middleware can translate it into a universal format for storing in a database.

Access the backends¶

Middleware manages connectivity to different back-end resources. A middleware can allow a fast and efficient access to a back-end database. In addition, middleware software can also manage connections to cloud resources.

Adapted information processing¶

A middleware can receive a request and determine data which will then be used to adapt the results. For example, a middleware application can detect a client browser’s default language for a specific request and return the adapted back-end responses so as to only display results in that language.

Another example is the geolocation of the client by its IP address: this information allows the server to return the most relevant data depending on the location.

IT Resource Management¶

Middleware plays an important role in concurrent processing, load distribution and transaction management. They are able to distribute incoming client requests across multiple servers, virtual machines, or availability zones in the cloud.

Middleware is also able to manage the conflicts that can arise when several clients make requests in parallel and try to access or modify specific information in the back-end. If application traffic increases, enterprise middleware can be configured to distribute client requests across multiple serverswhether on-premises or in the cloud.

Access rights control¶

The middleware monitors and secures access to back-end resources. he can request client access rights. This is done by a secure TLS connection and requires either authentication by identifiers with password, or a digital certificate. These security characteristics then make it possible to check whether the external client is authorized to access the data servers concerned. If permission is granted, data is sent from the middleware server to the client over a secure, encrypted connection.

What role does middleware play in companies?¶

The function of middleware is to enable communication between different systems. From current operations concerned in companies, we can cite:

• the management of financial transactions;
• employee security authentication programs;
• the coordinated provision of IT resources for the most demanding applications on the company’s servers.

The type of message to implement is determined by the company using the middleware. This decision depends on the services used in the structure and the type of data that the middleware will have to process.