What is mid­dle­ware?

Mid­dle­ware is a kind of trans­la­tion layer between an operating system and the ap­plic­a­tions running on it. This enables the exchange and man­age­ment of data when the operating system and ap­plic­a­tion aren’t com­pat­ible with each other.

What is mid­dle­ware and what does it do?

Mid­dle­ware is software that invisibly runs in the back­ground. It’s an ap­plic­a­tion that bridges an operating system with the programs running on it. It can be thought of as a hidden trans­lat­or, allowing dis­trib­uted ap­plic­a­tions to com­mu­nic­ate and manage one another. Mid­dle­ware can link two ap­plic­a­tions to support the exchange of data and databases. It’s also behind everyday ap­plic­a­tions like online submit forms or web page results that are tailored to your user profile. Mid­dle­ware can be thought of as a tool that exchanges two languages.

The de­vel­op­ment of mid­dle­ware

From 2000 until 2010, Mid­dle­ware software was syn­onym­ous with an ap­plic­a­tion server. With the growing pop­ular­ity of cloud computing and the re­place­ment of mono­lith­ic systems through mi­croservices, mid­dle­ware has changed.

Instead of deploying complete ap­plic­a­tions on mid­dle­ware servers, de­velopers tend to create smaller mi­croservices-based ap­plic­a­tions. These mi­croservices are packed with all the in­form­a­tion needed to connect to the required backend resources and deployed in a container-based system like Docker.

The Docker container is then deployed in a cloud-based service. Here, the mid­dle­ware combines the mi­croservice hosted in the container and the cloud computing in­fra­struc­ture on which the container runs. This means that fewer resources are consumed than with a con­ven­tion­al server or on a virtual machine.

What does mid­dle­ware mean?

The word ‘mid­dle­ware’ can be described as an in­ter­me­di­ate ap­plic­a­tion. It’s a service software that sits between user-side input on the frontend and queries and cal­cu­la­tions running in the backend. A client will typically run an ap­plic­a­tion in the frontend to interact with the software. Resources like databases, file servers, NoSQL data storages and message queues, on the other hand, often run in the backend. Mid­dle­ware sits in the middle between these two.

Typical char­ac­ter­ist­ics of mid­dle­ware

To be con­sidered mid­dle­ware, the software needs to meet various char­ac­ter­ist­ics and support different functions. Mid­dle­ware must:

• Work in­de­pend­ently of the existing hardware and the operating system
• Be in­de­pend­ent of the specific design of the network and the protocols used
• Not be dependent on a pro­gram­ming language
• Run unnoticed in the back­ground

What types of mid­dle­ware are there?

There are many kinds of mid­dle­ware, each developed for different ap­plic­a­tions in web and cloud services. Mid­dle­ware can be divided into three different areas:

Mid­dle­ware for com­mu­nic­a­tion

This type of software brings different types of networks onto the same level and enables their com­mu­nic­a­tion. You can find this ap­plic­a­tion in web services, where the HTTP protocol makes it possible for two computers to connect online re­gard­less of their operating systems.

Mid­dle­ware for messaging

This mid­dle­ware is used when two different ap­plic­a­tions want to exchange messages. How is de­term­ined by the mid­dle­ware. The ap­plic­a­tions involved can send and receive in­form­a­tion in this way. Web services use this software as well as the popular JSON (JavaS­cript Object Notation).

Mid­dle­ware for ap­plic­a­tions

Mid­dle­ware can be a pro­gram­ming language or operating system designed to work in a platform-in­de­pend­ent manner. You might be familiar with the .NET pro­gram­ming language, which is used to program ap­plic­a­tions for different operating systems. API mid­dle­ware provides de­velopers with tools to create, expose and manage ap­plic­a­tions, giving other de­velopers the pos­sib­il­ity to connect to them. RPC mid­dle­ware lets an ap­plic­a­tion trigger a procedure in another ap­plic­a­tion. This procedure can run on the same computer, another computer or over a network.

How does mid­dle­ware work?

On the most basic level, mid­dle­ware enables de­velopers to build ap­plic­a­tions without having to worry about custom in­teg­ra­tion every time they connect to ap­plic­a­tion com­pon­ents, data sources, computing resources or devices. It does this by providing services that let you com­mu­nic­ate over popular messaging frame­works. Examples of these frame­works include JSON (JavaS­cript Object Notation), REST (Rep­res­ent­a­tion­al State Transfer), XML (Ex­tens­ible Markup Language), SOAP (Simple Object Access Protocol) or web services.

As a rule, mid­dle­ware also provides services that enable com­mu­nic­a­tion between com­pon­ents written in different languages, like Java, C++, PHP and Python.

Where is mid­dle­ware used?

Most people work with mid­dle­ware every day without even knowing it. Here are some typical examples:

Cross-browser com­mu­nic­a­tion

Ap­plic­a­tions in web browsers are mostly managed by mid­dle­ware. Filling out contact forms or signing up for a news­let­ter are examples of this. It doesn’t matter which browser or operating system is used, mid­dle­ware can translate the request into a universal format and store it in a database.

Access to backends

Mid­dle­ware manages con­nectiv­ity to various backend resources. These com­pon­ents can provide fast and efficient access to a backend database. In addition, mid­dle­ware software can manage con­nec­tions to cloud-based resources.

User-cus­tom­ised pro­cessing

Mid­dle­ware can take a user request and output data used to customise the request results. For example, the mid­dle­ware ap­plic­a­tion can detect that a client browser making a par­tic­u­lar request has the language header set to English. The queries to the backend are adjusted so that only results in English are returned.

Another example is the geo­graph­ic location of the re­quest­ing client. Using the IP address, the server returns data that best matches the location.

Man­age­ment of computing resources

Mid­dle­ware plays an important role in con­cur­rent pro­cessing, load balancing and trans­ac­tion man­age­ment. It can dis­trib­ute incoming client requests across multiple servers, virtual machines or avail­ab­il­ity zones in the cloud.

Mid­dle­ware software can also manage conflicts that may arise when multiple clients attempt to access or modify a par­tic­u­lar piece of in­form­a­tion in the backend. As ap­plic­a­tion traffic increases, corporate mid­dle­ware can be set up to dis­trib­ute client requests across multiple servers, whether on premises or in the cloud.

Checking access rights

Mid­dle­ware monitors and secures access to backend resources. It can query the au­thor­isa­tion of clients. This requires a secure con­nec­tion via TLS and au­then­tic­a­tion, con­sist­ing of username and password, or a digital cer­ti­fic­ate. These security features are then used to check whether the external client can be granted access to the requested data servers. If au­thor­isa­tion is granted, the data is sent from the mid­dle­ware server to the client via a secure and encrypted con­nec­tion.

How do busi­nesses use mid­dle­ware?

The goal of mid­dle­ware is to enable com­mu­nic­a­tion between different systems. It can be used for:

• Man­age­ment of financial trans­ac­tions
• Programs for employee security au­thor­isa­tions
• Co­ordin­a­tion of compute-intensive ap­plic­a­tions on company servers

The message type used can be de­term­ined by the company using the mid­dle­ware. Such a decision depends on which services are used and what kind of data is to be processed by the mid­dle­ware.