Suggest a new Definition Show
Proposed definitions will be considered for inclusion in the Economictimes.com Definition: A web server is a computer that runs websites. It's a computer program that distributes web pages as they are requisitioned. The basic objective of the web server is to store, process and deliver web pages to the users. This intercommunication is done using Hypertext Transfer Protocol (HTTP). These web pages are mostly static content that includes HTML documents, images, style sheets, test etc. Apart from HTTP, a web server also supports SMTP (Simple Mail transfer Protocol) and FTP (File Transfer Protocol) protocol for emailing and for file transfer and storage. Description: The main job of a web server is to display the website content. If a web server is not exposed to the public and is used internally, then it is called Intranet Server. When anyone requests for a website by adding the URL or web address on a web browser’s (like Chrome or Firefox) address bar (like www.economictimes.com), the browser sends a request to the Internet for viewing the corresponding web page for that address. A Domain Name Server (DNS) converts this URL to an IP Address (For example 192.168.216.345), which in turn points to a Web Server. The Web Server is requested to present the content website to the user’s browser. All websites on the Internet have a unique identifier in terms of an IP address. This Internet Protocol address is used to communicate between different servers across the Internet. These days, Apache server is the most common web server available in the market. Apache is an open source software that handles almost 70 percent of all websites available today. Most of the web-based applications use Apache as their default Web Server environment. Another web server that is generally available is Internet Information Service (IIS). IIS is owned by Microsoft.
Related NewsA web service (WS) is either:
The use of the term "Web" in Web Service is a misnomer. Web Services do not use the World Wide Web (WWW), a human user interface running on the Internet, but rather a machine-to-machine service running on the Internet using the WWW protocols. In a web service, a web technology such as HTTP is used for transferring machine-readable file formats such as XML and JSON. In practice, a web service commonly provides an object-oriented web-based interface to a database server, utilized for example by another web server, or by a mobile app, that provides a user interface to the end-user. Many organizations that provide data in formatted HTML pages will also provide that data on their server as XML or JSON, often through a Web service to allow syndication. Another application offered to the end-user may be a mashup, where a Web server consumes several Web services at different machines and compiles the content into one user interface. Web services (generic)[edit]Asynchronous JavaScript And XML[edit]Asynchronous JavaScript And XML (AJAX) is a dominant technology for Web services. Developing from the combination of HTTP servers, JavaScript clients and Plain Old XML (as distinct from SOAP and W3C Web Services), now it is frequently used with JSON as well as, or instead of, XML. REST[edit]Main article: REST Representational State Transfer (REST) is an architecture for well-behaved Web services that can function at Internet scale. In a 2004 document, the W3C sets following REST as a key distinguishing feature of Web services:
Web services that use markup languages[edit]There are a number of Web services that use markup languages:
Web API[edit]A Web API is a development in Web services where emphasis has been moving to simpler representational state transfer (REST) based communications.[2] Restful APIs do not require XML-based Web service protocols (SOAP and WSDL) to support their interfaces. W3C Web services[edit]In relation to W3C Web services, the W3C defined a Web service as:
W3C Web Services may use SOAP over HTTP protocol, allowing less costly (more efficient) interactions over the Internet than via proprietary solutions like EDI/B2B. Besides SOAP over HTTP, Web services can also be implemented on other reliable transport mechanisms like FTP. In a 2002 document, the Web Services Architecture Working Group defined a Web services architecture, requiring a standardized implementation of a "Web service." Explanation[edit]Web services architecture: the service provider sends a WSDL file to UDDI. The service requester contacts UDDI to find out who is the provider for the data it needs, and then it contacts the service provider using the SOAP protocol. The service provider validates the service request and sends structured data in an XML file, using the SOAP protocol. This XML file would be validated again by the service requester using an XSD file. The term "Web service" describes a standardized way of integrating Web-based applications using the XML, SOAP, WSDL and UDDI open standards over an Internet Protocol backbone. XML is the data format used to contain the data and provide metadata around it, SOAP is used to transfer the data, WSDL is used for describing the services available and UDDI lists what services are available. A Web service is a method of communication between two electronic devices over a network. It is a software function provided at a network address over the Web with the service always-on as in the concept of utility computing. Many organizations use multiple software systems for management.[citation needed] Different software systems often need to exchange data with each other, and a Web service is a method of communication that allows two software systems to exchange this data over the Internet. The software system that requests data is called a service requester, whereas the software system that would process the request and provide the data is called a service provider. Different software may use different programming languages, and hence there is a need for a method of data exchange that doesn't depend upon a particular programming language. Most types of software can, however, interpret XML tags. Thus, Web services can use XML files for data exchange. Rules for communication with different systems need to be defined, such as:
All of these rules for communication are defined in a file called
WSDL (Web Services Description Language), which has a A directory called UDDI (Universal Description, Discovery, and Integration) defines which software system should be contacted for which type of data. So when one software system needs one particular report/data, it would go to the UDDI and find out which other systems it can contact for receiving that data. Once the software system finds out which other systems it should contact, it would then contact that system using a special protocol called SOAP (Simple Object Access Protocol). The service provider system would first validate the data request by referring to the WSDL file, and then process the request and send the data under the SOAP protocol. Automated design methods[edit]Automated tools can aid in the creation of a Web service. For services using WSDL, it is possible to either automatically generate WSDL for existing classes (a bottom-up model) or to generate a class skeleton given existing WSDL (a top-down model).
Criticism[edit]Critics of non-RESTful Web services often complain that they are too complex[8] and based upon large software vendors or integrators, rather than typical open source implementations. There are also concerns about performance due to Web services' use of XML as a message format and SOAP/HTTP in enveloping and transporting.[9] Regression testing of Web services[edit]Functional and non-functional testing of Web services is done with the help of WSDL parsing. Regression testing is performed by identifying the changes made to upgrade software. Web service regression testing needs can be categorized in three different ways, namely, changes in WSDL, changes in the code, and selective re-testing of operations. We can capture the above three needs in three intermediate forms of Subset WSDL,[7] namely, Difference WSDL (DWSDL), Unit WSDL (UWSDL), and Reduced WSDL (RWSDL), respectively. These three Subset WSDLs are then combined to form Combined WSDL (CWSDL) that is further used for regression testing of the Web service. This will help in Automated Web Service Change Management (AWSCM),[10] by performing the selection of the relevant test cases to construct a reduced test suite from the old test suite. [11] Web services testing can also be automated using several test automation tools like SoapUI, Oracle Application Testing Suite (OATS),[12][13] Unified Functional Testing, Selenium, etc. Web service change management[edit]Work-related to the capture and visualization of changes made to a Web service. Visualization and computation of changes can be done in the form of intermediate artifacts (Subset WSDL).[7] The insight on the computation of change impact is helpful in testing, top-down development and reduce regression testing. AWSCM[10] is a tool that can identify subset operations in a WSDL file to construct a subset WSDL. Discovering and Searching for Web Services[edit]While UDDI was intended to serve as a service directory and become the means to discovering web services, many vendors discontinued their UDDI solutions or repositories between 2005-2008, including Microsoft, SAP, IBM, among others.[14][15] A key study published in WWW2008 Conference (Beijing, China)[16] presented the state of SOAP-based web services and concluded that only 63% of the available SOAP-based web services at the time of the study were actually active or can be invoked. The study also found that search engines were becoming an ideal source for searching for web services compared to that of service registries like the UDDI due its design complexity.[17] See also[edit]
Notes[edit]
References[edit]
External links[edit]
What word is used to describe a language spoken between clients and servers on the Internet?HTTP: Hypertext Transfer Protocol is an application protocol that defines a language for clients and servers to speak to each other. This is like the language you use to order your goods.
Which of the following is used to define the contents of a webpage or group of pages?HTTP is the markup language used to specify the contents of a Web page. Which early browser was the first to run on multiple computer platforms including Windows?
What does Extensible mean in XML?“eXtensible” means that users may use XML to define their own data formats. Security Assertion Markup Language (SAML) is an XML-based framework for exchanging security information, including authentication data. Some forms of Single Sign-On (SSO) use SAML to exchange data.
Which of the following is a process by which virtual private networks transfer information by encapsulating traffic in IP packets over Internet?Wrapping is the process by which virtual private networks (VPNs) transfer information by encapsulating traffic in Internet Protocol (IP) packets over the Internet.
|