Re-Send HttpRequestMessage - Exception

Question

I want to send the exact same request more than once, for example:

HttpClient client = new HttpClient(); HttpRequestMessage req = new HttpRequestMessage(HttpMethod.Get, "http://example.com");  await client.SendAsync(req, HttpCompletionOption.ResponseContentRead); await client.SendAsync(req, HttpCompletionOption.ResponseContentRead); 

Sending the request for a second time will throw an exception with the message:

The request message was already sent. Cannot send the same request message multiple times.

Is their a way to "clone" the request so that I can send again?

My real code has more variables set on the HttpRequestMessage than in the example above, variables like headers and request method.

Answer 1

I wrote the following extension method to clone the request.

public static HttpRequestMessage Clone(this HttpRequestMessage req) {     HttpRequestMessage clone = new HttpRequestMessage(req.Method, req.RequestUri);      clone.Content = req.Content;     clone.Version = req.Version;      foreach (KeyValuePair<string, object> prop in req.Properties)     {         clone.Properties.Add(prop);     }      foreach (KeyValuePair<string, IEnumerable<string>> header in req.Headers)     {         clone.Headers.TryAddWithoutValidation(header.Key, header.Value);     }      return clone; } 

Answer 2

Here is an improvement to the extension method proposed by @drahcir. The improvement is to ensure the content of the request is cloned as well as the request itself:

public static HttpRequestMessage Clone(this HttpRequestMessage request) {     var clone = new HttpRequestMessage(request.Method, request.RequestUri)     {         Content = request.Content.Clone(),         Version = request.Version     };     foreach (KeyValuePair<string, object> prop in request.Properties)     {         clone.Properties.Add(prop);     }     foreach (KeyValuePair<string, IEnumerable<string>> header in request.Headers)     {         clone.Headers.TryAddWithoutValidation(header.Key, header.Value);     }      return clone; }  public static HttpContent Clone(this HttpContent content) {     if (content == null) return null;      var ms = new MemoryStream();     content.CopyToAsync(ms).Wait();     ms.Position = 0;      var clone = new StreamContent(ms);     foreach (KeyValuePair<string, IEnumerable<string>> header in content.Headers)     {         clone.Headers.Add(header.Key, header.Value);     }     return clone; } 

Edit 05/02/18: here's Async version

public static async Task<HttpRequestMessage> CloneAsync(this HttpRequestMessage request) {     var clone = new HttpRequestMessage(request.Method, request.RequestUri)     {         Content = await request.Content.CloneAsync().ConfigureAwait(false),         Version = request.Version     };     foreach (KeyValuePair<string, object> prop in request.Properties)     {         clone.Properties.Add(prop);     }     foreach (KeyValuePair<string, IEnumerable<string>> header in request.Headers)     {         clone.Headers.TryAddWithoutValidation(header.Key, header.Value);     }      return clone; }  public static async Task<HttpContent> CloneAsync(this HttpContent content) {     if (content == null) return null;      var ms = new MemoryStream();     await content.CopyToAsync(ms).ConfigureAwait(false);     ms.Position = 0;      var clone = new StreamContent(ms);     foreach (KeyValuePair<string, IEnumerable<string>> header in content.Headers)     {         clone.Headers.Add(header.Key, header.Value);     }     return clone; }