Web technologies

5 Key excerpts on "Web technologies"

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  eBook - ePub

  Dynamic Web Programming and HTML5

  • Paul S. Wang(Author)
  • 2012(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  Chapter 1

  The Web: An Overview

  Ever since its beginning in the early 1980s, the Web has been evolving and maturing. Today, the Web’s impact on how industries, governments, institutions, and individuals conduct business and socialize, is ever expanding. It is not surprising that the need for well-trained people to develop and program websites is increasing at a rapid pace.

  The Web involves networking, protocols, servers, clients as well as languages, services, and user interfaces. Thus, the Web is a rather complicated arena, and mastering Web development involves in-depth understanding and working experience with all the involved technologies and how to combine them for specific functions and effects.

  Even for people who will not become Web professionals, a good understanding of the Web, how it relates to the Internet, and what makes it tick will be valuable in many a workplace. The overview in this chapter sets up the scene and the context within which to study and apply the specific languages and programming techniques for building well-developed and dynamic websites.

  1.1 Web Is Part of the Internet

  For the vast majority of computer users, getting online means browsing the Web. That is how important the Web has become in our daily lives. But of course the Web is just one among many services available on the Internet. These include email, file transfer, remote login, audio and video streaming, and many more.

  The Internet spans the globe by connecting computer networks together. Such networks include local area networks (LANs) in office buildings, college campuses, and homes, as well as wide area networks (WANs) that cover whole cities or even countries. The Internet enables each connected computer, called a host, to communicate with any other hosts.

  In addition to host computers, the network infrastructure itself involves dedicated computers that perform network functions: hubs, switches, bridges, routers, and gateways. For programs and computers from different vendors, under different operating systems, to communicate on a network, a detailed set of rules and conventions must be established for all parties to follow. Such rules are known as networking protocols

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  eBook - ePub

  Developing Effective Websites

  A Project Manager's Guide

  • Roy Strauss, Patrick Hogan(Authors)
  • 2013(Publication Date)
  • Routledge

    (Publisher)

  www.w3c.org > are HTML and CSS (cascading style sheets) validation. The W3C website is a good place to check out established and evolving standards. The standards process is necessarily slow, subject to debate, discussion, and deliberations in order to negotiate a common middle ground among sometimes competing technologies. The standards cannot possibly keep up with the rate of innovation coming from individual companies. Website project managers should be able to distinguish between emerging technologies, which raise questions of portability and interoperability, and established standards, which are always safer but not cutting edge.

  SERVERS AND Web technologies

  Move over, you flashy designers and hotshot producers. The real action of the Web is on the server. Unfortunately, to much confusion, the term Web server is used interchangeably to refer to hardware, software, or both. At the most basic level, the server receives requests from the clients around the Internet and serves up the requested files. In sum, it performs a myriad of other functions that keep a website humming. The specialized services that are capturing the public’s interest in the Internet, such as e-commerce, distance learning, online auctions, or file-sharing services, all depend on sophisticated server software and programming.

  SERVER HARDWARE AND SOFTWARE

  The tasks that the machine performs define a server, not the hardware itself. Theoretically, just about any computer running any operating system can be used as a server, whether an old 486 desktop, a laptop, or a mainframe; however, Web servers are usually rack-mounted boxes with a powerful processor and lots of storage and memory.

  The location and spatial requirements of servers also vary. A small operation may serve its needs with a desktop computer. You will also see small racks or huge racks with hundreds of servers rarely touched by human hands. Fundamentally, the server is a computer that is attached to the Internet and can run the required software.

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  eBook - ePub

  The Web Application Hacker's Handbook

  Finding and Exploiting Security Flaws

  • Dafydd Stuttard, Marcus Pinto(Authors)
  • 2011(Publication Date)
  • Wiley

    (Publisher)

  Chapter 3 Web Application Technologies

  Web applications employ a myriad of technologies to implement their functionality. This chapter is a short primer on the key technologies that you are likely to encounter when attacking web applications. We will examine the HTTP protocol, the technologies commonly employed on the server and client sides, and the encoding schemes used to represent data in different situations. These technologies are in general easy to understand, and a grasp of their relevant features is key to performing effective attacks against web applications.

  If you are already familiar with the key technologies used in web applications, you can skim through this chapter to confirm that it offers you nothing new. If you are still learning how web applications work, you should read this chapter before continuing to the later chapters on specific vulnerabilities. For further reading on many of the areas covered, we recommend HTTP: The Definitive Guide by David Gourley and Brian Totty (O'Reilly, 2002), and also the website of the World Wide Web Consortium at www.w3.org .

  The HTTP Protocol

  Hypertext transfer protocol (HTTP) is the core communications protocol used to access the World Wide Web and is used by all of today's web applications. It is a simple protocol that was originally developed for retrieving static text-based resources. It has since been extended and leveraged in various ways to enable it to support the complex distributed applications that are now commonplace.

  HTTP uses a message-based model in which a client sends a request message and the server returns a response message. The protocol is essentially connectionless: although HTTP uses the stateful TCP protocol as its transport mechanism, each exchange of request and response is an autonomous transaction and may use a different TCP connection.

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  eBook - ePub

  Beyond E-Business

  Towards networked structures

  • Paul Grefen(Author)
  • 2015(Publication Date)
  • Routledge

    (Publisher)

  Figure reproduced with permission of Yahoo!. ©2014 Yahoo!. FLICKR and the Flickr logo are registered trademarks of Yahoo!.

  The application of web 2.0 technologies can contribute to increasing the richness of e-business communication (as discussed in section 5.2 ). Not everybody is convinced of the web 2.0 concept, though. This is not because the developments mentioned by web 2.0 enthusiasts are not considered important (there is little doubt about that), but because these developments can also be seen as a continuous evolution, such that there are no ‘two versions’ of the web but, rather, a continuum in time of new possibilities.

  8.2.3 Some brief remarks

  Two trivial but important remarks need to be made here to avoid the confusion that is often encountered ‘in practice’:

  • First, the internet and the web are not the same thing (although many use the terms in an interchangeable fashion). The web is a hypertext based information structure using the internet as underlying communication technology. So, technically speaking, one cannot ‘surf the internet’ the same as one ‘surfs the web’.
  • Second, protocols and languages (for internet or web) are different things, although they are often intermixed. Protocols are used to specify how communication takes place, languages to specify what is communicated. In other words, put very simply: protocols are about transport, languages are about content.

  Now that we have discussed the internet and web as the ‘bare basic’ technologies for networked e-business, we move on to more advanced technologies, starting with advanced infrastructure technology.

  8.3 Advanced infrastructure technology

  Advanced infrastructure technology provides a broad, general-purpose software platform for the implementation of networked e-business systems. This class of technology provides two main elements:

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  eBook - ePub

  Full Stack Web Development

  The Comprehensive Guide

  • Philip Ackermann(Author)
  • 2023(Publication Date)
  • SAP PRESS

    (Publisher)

  5    Using Web Protocols

  This chapter provides an overview of the most important web protocols you should know as a full stack developer.

  So far, we’ve covered the most important languages for web development: Hypertext Markup Language (HTML), Cascading Style Sheets (CSS), and JavaScript. In addition to these languages, however, as a full stack developer, you must be familiar with web protocols and understand their basic functionality. Thus, in the first part of this chapter, I want to return to HTTP in more detail, before I introduce you to the WebSocket protocol, among others, through which bidirectional communication between client and server is possible, in the second part of this chapter.

  Figure 5.1     Web Protocols Control Communications between Client and Server

  5.1    Hypertext Transfer Protocol

  Basically, web protocols define the way clients and servers communicate with each other. When you open a web page in the browser, dozens of requests are made in the background by the client (or browser) to the server, depending on the web page: Each image, CSS file, and JavaScript file included in the web page results in a separate request sent from the browser to the server and processed by it. The protocol used between the browser (or client ) and the server is HTTP .

  Tip

  In all modern browsers, you can look at the communication between client and server via a browser’s developer tools. Try it! In Chrome, for example, you can open Chrome DevTools via View • Developers • Developer Tools . Then, select the Network section in the window that opens and reload the corresponding web page. (This manual step is necessary because the developer tools do not record network traffic by default.) Figure 5.2 , for example, shows clearly what happens when the web page www.rheinwerk-computing.com

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