HttpRequestMessage在多IP环境中配置IP

Question

我在主机上有几个IP，并且想要从HttpClient与HttpRequestMessage建立连接时选择使用哪一个IP。如果没有我自己去插座并自己编写一个简单的http客户端，这可以做到吗？

我在找的相当于connect的socket的等级，但是对于HttpClient ......或其他选择。

Answer 1

所以，如果你使用的是Windows计算机上的默认HttpClient消息处理程序，HttpClient将使用.net HttpWebRequest做其工作。这又依靠ServicePointManager来提供ServicePoint来管理到URI的连接。对于任何域，您可以挂钩到其ServicePoint以更改绑定到IPEndPoint的方式。

如果你把你正在试图连接到并找到其ServicePoint的URI：

var sp = ServicePointManager.FindServicePoint(uri); 

那么你可以：

var sp = ServicePointManager.FindServicePoint(new Uri("http://www.google.com")); 
sp.BindIPEndPointDelegate = (servicePoint, remoteEndPoint, retryCount) => { 
    IPAddress adapterIpAddress = //your chosen adapter's IP address 
    return new IPEndPoint(adapterIpAddress, 0); 
}; 

如果你想获得真正的爵士，你可以折叠这成一个DelegatingHandler，以便HttpClient为您处理所有事情：

public class RebindingHandler : DelegatingHandler 
{ 
    private BindIPEndPoint bindHandler; 
    public RebindingHandler(IEnumerable<IPAddress> adapterAddresses, 
          HttpMessageHandler innerHandler = null) 
     : base(innerHandler ?? new WebRequestHandler()) 
    { 
     var addresses = adapterAddresses.ToList(); 
     if(!addresses.Any()) 
     { 
      throw new ArgumentException(); 
     } 
     var idx = 0; 
     bindHandler = (servicePoint, remoteEndPoint, retryCount) => { 
      int i = Interlocked.Increment(ref idx); 
      uint i2 = unchecked((uint)i); 
      int index = (int)(((long)i2) % addresses.Count); 

      IPAddress adapterIpAddress = addresses[index]; 
      return new IPEndPoint(adapterIpAddress, 0); 
     }; 
    } 

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, 
     CancellationToken cancellationToken) 
    { 
     var sp = ServicePointManager.FindServicePoint(request.RequestUri); 
     sp.BindIPEndPointDelegate = bindHandler; 
     var httpResponseMessage = await base.SendAsync(request, cancellationToken); 
     return httpResponseMessage; 
    } 
} 

然后，您可以：

var addresses = new List<IPAddress>(); //this contains your adapter addresses 
var client = new HttpClient(new RebindingHandler(addresses)); 

，当你使用client，内部处理程序将自动注册相关的ServicePoint使用周围一堆IPEndPoints的旋转的BindIPEndPoint。