The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.
Do not use the HttpWebRequest constructor. Use the System.Net.WebRequest.Create method to initialize new HttpWebRequest objects. If the scheme for the Uniform Resource Identifier (URI) is http:// or https://, Create returns an HttpWebRequest object.
The GetResponse method makes a synchronous request to the resource specified in the RequestUri property and returns an HttpWebResponse that contains the response. You can make an asynchronous request to the resource using the BeginGetResponse and EndGetResponse methods.
When you want to send data to the resource, the GetRequestStream method returns a Stream object to use to send data. The BeginGetRequestStream and EndGetRequestStream methods provide asynchronous access to the send data stream.
For client authentication with HttpWebRequest, the client certificate must be installed in the My certificate store of the current user.
The HttpWebRequest class throws a WebException when errors occur while accessing a resource. The WebException.Status property contains a WebExceptionStatus value that indicates the source of the error. When WebException.Status is WebExceptionStatus.ProtocolError, the Response property contains the HttpWebResponse received from the resource.
HttpWebRequest exposes common HTTP header values sent to the Internet resource as properties, set by methods, or set by the system; the following table contains a complete list. You can set other headers in the Headers property as name/value pairs. Note that servers and caches may change or add headers during the request.
The following table lists the HTTP headers that are set either by properties or methods or the system.
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| HttpWebRequest is registered automatically. You do not need to call the RegisterPrefix method to register System.Net.HttpWebRequest before using URIs beginning with http:// or https://. |
If the local computer configuration specifies that a proxy be used, or if the request specifies a proxy, the request is sent using the proxy. If no proxy is specified, the request is sent to the server.
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| The Framework caches SSL sessions as they are created and attempts to reuse a cached session for a new request, if possible. When attempting to reuse an SSL session, the Framework uses the first element of ClientCertificates (if there is one), or tries to reuse an anonymous sessions if ClientCertificates is empty. |
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| For security reasons, cookies are disabled by default. If you want to use cookies, use the CookieContainer property to enable cookies. |