Lets See some Basic WWW HTTP study notes
The World Wide Web (WWW) is a repository of information linked together from
points all over the world.
Hypertexts are documents linked to one another through the concept of pointers.
Browsers interpret and display a Web document.
A browser consists of a controller, client programs, and interpreters.
A Web document can be classified as static, dynamic, or active.
A static document is one in which the contents are fixed and stored in a server. The
client can make no changes in the server document.
Hypertext Markup Language (HTML) is a language used to create static Web pages.
Any browser can read formatting instructions (tags) embedded in an HTML
document.
Tags provide structure to a document, define titles and headers, format text, control
the data flow, insert figures, link different documents together, and define executable code.
A dynamic Web document is created by a server only at a browser request.
The Common Gateway Interface (CGI) is a standard for creating and handling
dynamic Web documents.
A CGI program with its embedded CGI interface tags can be written in a language
such as C, C++, Shell Script, or Perl.
An active document is a copy of a program retrieved by the client and run at the
client site.
Java is a combination of a high-level programming language, a run-time environment, and a class library that allows a programmer to write an active document and
a browser to run it.
Java is used to create applets (small application programs).
The Hypertext Transfer Protocol (HTTP) is the main protocol used to access data
on the World Wide Web (WWW).
HTTP uses a TCP connection to transfer files.
An HTTP message is similar in form to an SMTP message.
The HTTP request line consists of a request type, a URL, and the HTTP version
number.
The uniform resource locator (URL) consists of a method, host computer, optional
port number, and path name to locate information on the WWW.
The HTTP request type or method is the actual command or request issued by the
client to the server.
The status line consists of the HTTP version number, a status code, and a status
phrase.
The HTTP status code relays general information, information related to a successful
request, redirection information, or error information.
The HTTP header relays additional information between the client and server.
An HTTP header consists of a header name and a header value.
An HTTP general header gives general information about the request or response
message.
An HTTP request header specifies a client’s configuration and preferred document
format.
An HTTP response header specifies a server’s configuration and special information
about the request.
An HTTP entity header provides information about the body of a document.
HTTP, version 1.1, specifies a persistent connection.
A proxy server keeps copies of responses to recent requests.