Hypertext Transfer Protocol

See http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol

Please watch carefully the video on http://www.youtube.com/watch?v=kGOpY2J31pI. Besides documentation please
 answer the following questions:



Which request methods are used at HTTP? Which method do you use for which purpose?

 -HEAD
Asks for the response identical to the one that would correspond to a GET request, but without the response body. This is useful for retrieving meta-information written in response headers, without having to transport the entire content.



-POST
Requests that the server accept the entity enclosed in the request as a new subordinate of the web resource identified by the URI. The data POSTed might be, for example, an annotation for existing resources; a message for a bulletin board, newsgroup, mailing list, or comment thread; a block of data that is the result of submitting a web form to a data-handling process; or an item to add to a database.


-PUT
Requests that the enclosed entity be stored under the supplied URI. If the URI refers to an already existing resource, it is modified; if the URI does not point to an existing resource, then the server can create the resource with that URI.


-DELETE
Deletes the specified resource.


-TRACE
Echoes back the received request so that a client can see what (if any) changes or additions have been made by intermediate servers.


-OPTIONS
Returns the HTTP methods that the server supports for the specified URL. This can be used to check the functionality of a web server by requesting '*' instead of a specific resource.


-CONNECT
Converts the request connection to a transparent TCP/IP tunnel, usually to facilitate SSL-encrypted communication (HTTPS) through an unencrypted HTTP proxy. See HTTP CONNECT Tunneling.


-PATCH
Applies partial modifications to a resource.
HTTP servers are required to implement at least the GET and HEAD methods and, whenever possible, also the OPTIONS method.[citation needed]

• Do GET requests modify data on the server?

No.

• When is a GET request transmitted to a server?

When you request data form a server.

• What is the difference between GET and POST requests?

At GET-Requests, you doesn't modify the server. At POST-Requests you modify, you add something to the server.

• When you log in to a server, which method is usually used?

Usually the POST-method is used,