The HTTP protocol defines methods to indicate the action to be performed on the Web server for the particular URL resource identified by the client (e.g. your Web browser or our CheckUpDown robot). The methods are as follows:
OPTIONS: Find out the communication options available for a particular URL resource. Allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without a specific action involving transfer of data.
GET: Retrieve the information identified by the URL resource
e.g. GET a particular Web page or image. The most common method by far.
HEAD: Identical to GET except that the server returns header information only, not the actual information identified by the URL resource. Useful to obtain metainformation about the entity implied by the request without transferring the entity-body itself. Often used to test hypertext links for validity, accessibility, and recent modification.
POST: Submit data to the Web server such as
1) post a message to a bulletin board, newsgroup or mailing list,
2) provide input data – typically from a CGI form – to a data-handling process,
3) add a record directly to a database.
PUT: Set (place/replace) the data for a particular URL to the new data submitted by the client.
For example, upload a new Web page to a server.
DELETE: Remove the data associated with the URL resource.
For example, delete a Web page.
TRACE: Run a remote, application-layer loop-back of the request message. Effectively a ‘ping’ which tests what data the Web server is receiving from the client.
CONNECT: Reserved for use with tunneling (e.g. SSL) via a proxy server. This method is defined only for HTTP version 1.1, not the earlier version 1.0.