Web services

 

The birth of web services

The birth of computer science, the science of computers, has caused a technological revolution of epochal importance in the history of humanity. Starting from the middle of the last century, when the first electronic calculators were built, information technology has experienced a rapid and constant development that has led to a pervasive presence of applications in all sectors of society. The impressive expansion of computer networks, particularly the Internet, has allowed a widespread diffusion of the use of network applications, such as e-mail or web browsing, among hundreds of millions of users on our planet. At the beginning of this new century, we are now used to the constant presence of computer applications at all times of the day, from work to information and entertainment. On-demand, VoIP ( Voice over Internet Protocol ) telephony, home automation, or telemedicine. Universal solz provide the best website development services..

To better understand the fundamental aspects of the developments (past, present, and future) of information technology, it is helpful to remember the distinction between the concepts of hardware and software. Historically, the term hardware refers to the metal parts of artifacts made from wood. In the modern sense, the term is used to indicate hardware items in general (in the United States, hardware stores are called hardware stores .). In the IT world, the term is used to refer to all the physical - that is, tangible - components of a computer (circuits, keyboards, monitors, cables, and so on), as opposed to the intangible elements (programs, applications, operating systems) that constitute the software present inside a computer.

The impetuous development of IT applications was determined by the significant evolutions in both sectors, hardware, and software, of IT. The large-scale integration of electronic circuits (VLSI, Very Large Scale Integration) led to the creation of tiny chips containing millions of transistors and handheld computers (the size of the palm of a hand) more potent than the first electronic computers (which occupied entire buildings). The enormous steps forward in the telematics sector have also allowed the creation and diffusion of very high-speed physical networks, the integration of which allows the almost instantaneous transmission of large quantities of information from one side of the planet to the other. However, the impressive developments in hardware would not have allowed today's computer applications to be realized if they had not been accompanied by equally essential products in the software sector.

One of the crucial aspects of the success of both hardware and software products is ​​creating sophisticated components by appropriately combining simpler parts that already exist. As mentioned, the large-scale integration of standardized electronic components has been the leitmotif of the unstoppable evolution of hardware in information technology. Similarly, the evolution of programming languages ​​has tried to make the development of complex applications ever easier through the appropriate combination of more straightforward existing software.

An entire sector of information technology, the so-called software engineering, has been dedicated in recent decades to the definition of methodologies and techniques that would allow a disciplined development of applications based on the integration of software components. The idea is, in essence, to design each application by decomposing its logic and functionality into smaller parts, each of which is offered by existing software, and thus specifying, in an appropriate way, only the necessary interaction between all the components. Such a modular software development has introduced enormous advantages in production, allowing the reusability of components already developed (and tested) and, consequently, drastically reducing the time and costs of the production of new applications and their subsequent maintenance.

The well-established practice of developing IT applications by appropriately combining existing software components is destined to be further strengthened, with multiple implications, which we will mention later, thanks to the recent birth of the so-called web services. As a first approximation, a web service is a software component that can be identified and used on the network by other software components through public domain standards. From this first informal definition, it is easy to understand the profound impact that the spread of web services, which began at the dawn of this new century, is destined to have on the future developments of computer applications. The possibility that applications are built, through the integration of various services present in different places and offered by other subjects,

Web sites and services

As we have already mentioned, a web service can be roughly considered a software component that other software components can use over the network.

An essential difference between websites and web services is worth pointing out right away. A website is a set of documents (also called web pages ) organized in a hypertext structure and accessible on the network with special programs ( browsers ). Each website has an associated address (URL, Uniform Resource Locator ), which allows you to access the documents it contains. For example, by entering the address www. treccani. In a browser, we can view the contents of the main page of the website of the Italian Encyclopedia Institute. An essential difference between websites and web services is that, while the former offer information (in text, images, or sounds) intended for users, the latter offer operations to other software components.

Let's use a simple example to illustrate the difference between the two concepts. Let's consider a hotel website that allows customers to check room availability for specific dates and make reservations for the desired period. The user can then use their browser to carry out the various operations, entering the necessary data (arrival and departure days, number of rooms, and, possibly, personal information such as name, credit card number, and so on). For example, the website will initially present a window similar to the one shown in Figure 1. The same operations can also be offered by a web service but presented in a machine-understandable format that other computers understand, with a syntax like the one shown in figure 1 B.

Despite its extreme simplicity, the example allows us to appreciate the clear difference between how a user interacts with a website and the language software used to interact with a web service. For example, in figure 1 B, we can see how many syntactic details of the operation are specified: the name (Check Availability), the three parameters that the process must receive as input (Irradiation, Departmentalize, and Nonnumerical), as well as the parameter that the operation will return (Result) at the end of its execution.

Furthermore, how websites and web services present the operations that users can perform differently and how the latter can request the execution of these operations is different. For example, website users typically use a browser program that allows them, through a graphic interface using mouse and keyboard, to enter data and select the operation to perform. On the other hand, web service customers do not use any graphical interface. Instead, communication takes place through messages with which users specifically request the execution of operations and, therefore, receive such performance.

 

As we will deepen further on, the ease with which other software components can use web services has opened new horizons for the development of IT applications, greatly simplifying their implementation by integrating different services available in different parts of the planet. developed and offered by various parties.

 

One of the simplest examples used to illustrate the advantages of using and integrating web services is creating an application that allows a user to organize his holidays. For some years now, it has been possible to use the web to plan holidays independently by purchasing, for example, tickets on an airline's website and booking the stay on the website of a hotel, after having examined different offers of flights and stays described in other sites. The Availability of web services that allow other software components to purchase flights and book stays has permitted the creation of innovative services obtained by integrating the basic ones.

 

For example, at this point, it is easy to imagine how software can be created that can book the cheapest stay available on specific dates. Intuitively, this software will request Availability and prices from a set of web services of different hotels, then compare the results received and select the best offer. Similarly, it is possible to obtain software that books the cheapest flights to a specific destination in the desired period.

Therefore, it is evident how the ease with which different web services can be used allows the creation of applications that make up these services, offering an added value compared to them. Continuing our example, we can quickly obtain an application that can book the cheapest stay and flights on specific dates and maybe even, for example, a car rental or theatrical performances offered by other web services.

Naturally, the created application can, in turn, be presented as a web service (to allow its use by other applications) and also on a website (to allow its use by users). .universal solz the best it services company in USA.