RequestParameter

RequestParameter is a term used to describe a parameter sent by a client as part of an HTTP request to a server. Such parameters carry data that can influence server-side processing, control the behavior of an endpoint, or supply information needed to generate a response. They are a fundamental concept in web APIs and RESTful services.

Request parameters appear in several forms. The most common is a query parameter, which is included in the URL query string (for example, /search?q=term&page=2). Path parameters are embedded within the URL path itself (for example, /users/{id}). Parameters can also be conveyed via HTTP headers, cookies, or in the request body (such as form data or JSON) when using methods like POST or PUT. Some frameworks provide specialized mechanisms or annotations to bind these parameters to server-side variables or objects.

Retrieving a RequestParameter depends on the framework or language. Examples include reading query parameters from a request object (for example, req.query.q in Node.js, or request.args.get('q') in Python Flask) or mapping path or header values to function arguments. Validation, type conversion, and default values are commonly applied to ensure robust handling of parameters.

Common uses include filtering, pagination, sorting, authentication, and feature toggles. Design considerations emphasize security (input validation and encoding to prevent injections), privacy (minimizing exposure of sensitive data in URLs), and performance (avoiding large, unnecessary parameters). While RequestParameter is not a single runtime object, it represents the many name-value pairs transmitted by clients to influence server behavior.

See also: HTTP query string, URL encoding, RESTful design, API security.