HTTP Requests and Web Server

HTTP:

It is a type of protocol which deals with the web information regarding to the client request. It provides some security for the demanding URLs (Unified/Uniform Resource Locater). Common URL refers to files, directories, or objects that perform complex tasks like database lookup and internet searches.

There are two types of requests available for the HTTP –

                               I.            HTTP GET request

                             II.            HTTP POST request

For each request there are some response should provide from the other side (server).

                               I.            HTTP GET request:

The word get is an HTTP method indicating that client wants to obtain a resource from server. The remainder of the request provides the path name of the resource, protocol name and version number with some optional headers.

                             II.            HTTP POST request:

The HTML post method typically post data to a server so the common uses of post request is to send some form of data or document to a server.

Web server:

                               I.            IIS web server

                             II.            Apache web server

To request document from servers users must know the host names on which the web server software exist. Users can request documents from local web server (client computer) or remote web server.

            Web server can be access through the computer name or through the local host.

Local Host: Host name that references the local machine & normally translates to the IP address 127.0.0.1 (loopback address).

1.     Microsoft IIS (Internet Information Services) server:

Microsoft IIS is a web server that is included with several versions of windows so IIS enables a computer to serve documents. To install IIS server open the “Add or Remove program” from control panel. Click on “Add/Remove windows components”. Then check the checkbox next to internet information services & click next. But it is necessary to keep the original windows operating system disk to complete the installation. There are different versions available of IIS that are IIS 5.1, IIS 6.0 & the latest version is IIS 7.0 & these versions typically uses HTTP.

2.     Apache server:

The apache HTTP server is maintained by apache software foundation. It is currently most popular web server because of its stability, efficiency, portability, security and small size. It is open source software that runs on UNIX, Linux, Windows, Mac OS and many other operating systems.

      In Mac OS and Linux apache is pre installed. After installation of apache HTTP server start the application from the program menu, Click on apache HTTP server then click on control apache server then click on monitor apache server. And if it is necessary for sharing the data, it could be possible from the system preference tab and opening the sharing preference tab and opening the sharing preference pane and click the checkbox next to web share.

Multitier application:

Web based applications are multitier application and sometimes it is called as n-tier application. It is divided functionally into separate tiers. It may be possible that tiers can locate on the same computer. The tiers of web based application generally reside on separate computers.

      Here the diagram represents basic structure of a three tier web based application –

Data or Information tier:

The bottom tier is known as data or information tier which maintains the application’s data. This tier stores data in a relational database management system. This may reside on one or more computers which together comprised the application’s data.

Business logic tier:

The middle tier is known as business logic tier which control information between the application data and its client.

Client tier:

This tier is user interface. It converts tasks into user understandable format.