HTTP Pocket Reference

POST: Send Data to the Server

The POST method allows the client to specify data to be sent to some data-handling program that the server can access. It can be used for many applications. For example, POST could be used to provide input for:

• CGI programs

• Gateways to network services, like an NNTP server

• Command-line interface programs

• Annotation of documents on the server

• Database operations

In practice, POST is used with CGI programs that happen to interface with other resources like network services and command-line programs. In the future, POST may be directly interfaced with a wider variety of server resources.

In a POST request, the data sent to the server is in the entity-body of the client’s request. After the server processes the POST request and headers, it may pass the entity-body to another program (specified by the URL) for processing. In some cases, a server’s custom API may handle the data, instead of a program external to the server.

POST requests should be accompanied by a Content-type header, describing the format of the client’s entity-body. The most commonly used format with POST is the URL-encoding scheme used for CGI applications. It allows form data to be translated into a list of variables and values. Browsers that support forms send the data in URL-encoded format. For example, given the HTML form of:

<title>Create New Account</title> <center><hr><h1>Account Creation Form</h1><hr></center> <form method="post" action="/cgi-bin/create.pl"> <pre> <b> Enter user name: <INPUT ...