webAPI获得链接客户端IP地址

public static class HttpRequestMessageExtensions
{
private const string HttpContext = "MS_HttpContext";
private const string RemoteEndpointMessage =
"System.ServiceModel.Channels.RemoteEndpointMessageProperty";
private const string OwinContext = "MS_OwinContext";

public static string GetClientIpAddress(this HttpRequestMessage request)
{
// Web-hosting. Needs reference to System.Web.dll
if (request.Properties.ContainsKey(HttpContext))
{
dynamic ctx = request.Properties[HttpContext];
if (ctx != null)
{
return ctx.Request.UserHostAddress;
}
}

// Self-hosting. Needs reference to System.ServiceModel.dll.
if (request.Properties.ContainsKey(RemoteEndpointMessage))
{
dynamic remoteEndpoint = request.Properties[RemoteEndpointMessage];
if (remoteEndpoint != null)
{
return remoteEndpoint.Address;
}
}

// Self-hosting using Owin. Needs reference to Microsoft.Owin.dll.
if (request.Properties.ContainsKey(OwinContext))
{
dynamic owinContext = request.Properties[OwinContext];
if (owinContext != null)
{
return owinContext.Request.RemoteIpAddress;
}
}

return null;
}
}