HttpRequestMessage

HttpRequestMessage is a class in the System.Net.Http namespace that represents an HTTP request message to be sent by an HTTP client such as HttpClient or HttpMessageInvoker. It encapsulates the components of a request, including the HTTP method, target URI, headers, and optional content, along with a protocol version and a per-request data store. This object-oriented representation allows fine-grained control over the request configuration before it is transmitted.

Constructors available for HttpRequestMessage enable initializing a request with a specific method and URI, either by providing a Uri or a string that can be converted to a Uri. The default constructor creates an empty request that can be populated programmatically. The primary properties exposed are Method (HttpMethod), RequestUri (Uri), Version (Version), Content (HttpContent), and Headers (HttpRequestHeaders). The Content property allows access to content-specific headers through Content.Headers, and the request-wide headers are accessible via the Headers collection. A per-request data dictionary (Properties) allows callers to attach auxiliary data to the message for use by handlers or middleware.

Usage typically involves constructing an HttpRequestMessage, setting the desired method and URI, optionally attaching a request body through Content for methods such as POST or PUT, and configuring headers. The configured request is then passed to an HttpClient’s SendAsync method (or similar) to perform the HTTP operation, after which the response is processed. HttpRequestMessage is disposable, and should be disposed when no longer needed to release resources associated with the request content.

This class is widely used in .NET applications to programmatically assemble and customize HTTP requests in a structured, strongly typed way, enabling scenarios ranging from simple GET requests to complex, header-rich interactions.