applications to make HTTP requests. You can even send an HTTP request by hand
using a standard utility such as Telnet. When the HTTP response comes back, it is
also in plain text that developers can read.
The first line in the HTTP request contains the method, followed by the location
of the requested resource and the version of HTTP. Zero or more HTTP request
headers follow the initial line. The HTTP headers provide additional information to
the server. This can include the browser type and version, acceptable document types,
and the browser’s cookies, just to name a few. Of the seven request methods, GET
and POST are by far the most popular.
Once the server has received and serviced the request, it will issue an HTTP
response. The first line in the response is called the status line and carries the HTTP
protocol version, a numeric status, and a brief description of the status. Following the
status line, the server will return a set of HTTP response headers that work in a way
similar to the request headers.
As we mentioned, HTTP does not preserve state information between
requests.The server logs the request, sends the response, and goes blissfully on to the
next request. While simple and efficient, a stateless protocol is problematic for
dynamic applications that need to keep track of their users. (Ignorance is not always
bliss.
Cookies and URL rewriting are two common ways to keep track of users
between requests. A cookie is a special packet of information on the user’s computer.
URL rewriting stores a special reference in the page address that a Java server can use
to track users. Neither approach is seamless, and using either means extra work when
developing a web application. On its own, a standard HTTP web server does not
traffic in dynamic content. It mainly uses the request to locate a file and then returns
that file in the response. The file is typically formatted using Hypertext Markup
Language (HTML) [W3C, HTML] that the web browser can format and display. The
HTML page often includes hypertext links to other web pages and may display any
number of other goodies, such as images and videos. The user clicks a link to make
another request, and the process begins a new.
Standard web servers handle static content and images quite well but need a
helping hand to provide users with a customized, dynamic response.
DEFINITION:Static content on the Web comes directly from text or data files,