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.