REQUESTMETHOD

REQUESTMETHOD is a term commonly used to refer to the HTTP request method that a client uses to interact with a server. In CGI and related server environments, the standard environment variable is REQUEST_METHOD (uppercase with an underscore), which conveys the method such as GET, POST, PUT, DELETE, OPTIONS, HEAD, PATCH, or TRACE. The concept of a request method is central to how servers interpret and route client requests.

Origin and usage

In CGI scripts, the server populates the REQUEST_METHOD variable from the actual HTTP method and scripts read it to determine how to process input. Many programming environments provide a similar property (for example, request.method in many web frameworks), but REQUEST_METHOD remains the classic, server-provided value for legacy compatibility and simple scripts.

Examples

In a CGI script, code may check if ENV['REQUEST_METHOD'] == 'POST' to process form data. In PHP, the corresponding value is available as $_SERVER['REQUEST_METHOD'], which yields 'POST' or 'GET' among other methods.

Relation to REST and safety

GET and HEAD are typically safe and idempotent, while methods like POST, PUT, and DELETE are not guaranteed to be harmless or idempotent. Applications often validate and restrict allowed methods to enforce correct behavior and security.

Security and interoperability

Some environments support method tunneling, using a POST request with a special parameter to override the effective method, accommodating clients that cannot send certain methods. Frameworks and servers may implement such overrides, while keeping the original REQUEST_METHOD information available.

See also

HTTP, HTTP methods, REST, CGI, REQUEST_METHOD, request.method.