POST (HTTP)

In computing, POST is a request method supported by the HTTP protocol used by the World Wide Web. By design, the POST request method requests that a web server accept and store the data enclosed in the body of the request message. It is often used when uploading a file or when submitting a completed web form.

In contrast, the HTTP request method is designed to retrieve information from the server. As part of a GET request, some data can be passed within the URL's query string, specifying (for example) search terms, date ranges, or other information that defines the query.

As part of a POST request, an arbitrary amount of data of any type can be sent to the server in the body of the request message. A header field in the POST request usually indicates the message body's Internet media type.

The World Wide Web and HTTP are based on a number of request methods or 'verbs', including POST and GET as well as PUT, DELETE, and several others. Web browsers normally use only GET and POST, but RESTful online apps make use of many of the others. POST's place in the range of HTTP methods is to send a representation of a new data entity to the server so that it will be stored as a new subordinate of the resource identified by the URI. For example, for the URI http://example.com/customers, POST requests might be expected to represent new customers, each including their name, address, contact details and so on. Early website designers strayed away from this original concept in two important ways. First, there is no technical reason for a URI textually to describe the web resource subordinate to which POST data will be stored. In fact, unless some effort is made, the last part of a URI will more likely describe the web application's processing page and its technology, such as http://example.com/applicationform.php. Secondly, given most web browsers' natural limitation to use only GET or POST, designers felt the need to re-purpose POST to do many other data submission and data management tasks, including the alteration of existing records and their deletion.

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