HttpResponseMessage

HttpResponseMessage is a class in the System.Net.Http namespace that represents an HTTP response message returned by HttpClient and related APIs. It encapsulates the status line, headers, and body of the response, providing access to both the response metadata and the content.

Key members include StatusCode (an HttpStatusCode enum), ReasonPhrase (a string with the textual reason), Version (the HTTP version), Headers (HttpResponseHeaders), Content (HttpContent), and RequestMessage (the HttpRequestMessage that initiated the response when available). The IsSuccessStatusCode property indicates whether the status code is in the 2xx range. The Content property can hold various content types such as StringContent, ByteArrayContent, or StreamContent, and content headers are exposed via Content.Headers.

Constructors for HttpResponseMessage include a parameterless constructor and one that takes an HttpStatusCode to initialize the status code immediately. The object is typically populated by the HTTP client stack and can be customized by assigning Content, adjusting headers, or setting the Version.

Usage patterns involve obtaining a response from HttpClient methods like GetAsync, SendAsync, or PostAsync. After receiving a response, code commonly checks response.IsSuccessStatusCode or calls EnsureSuccessStatusCode() to throw an exception for non-success statuses. The response body is read asynchronously via Content.ReadAsStringAsync(), ReadAsByteArrayAsync(), or ReadAsStreamAsync(). Resources should be released by disposing the HttpResponseMessage (and its Content) when processing completes.

Notes: HttpResponseMessage is not generally reusable across multiple requests. The RequestMessage, when set, reflects the originating request. Proper disposal is important to free network and stream resources. See also HttpClient, HttpRequestMessage, HttpContent, and HttpResponseHeaders.