C# HttpClient GetAsync exception "The server returned an invalid or unrecognized response"

Question

This seems to be a random issue. Sometimes the GetAsync successfully gets a response (200/OK). Other times it throws an exception. I'm thinking it has something to do with the "Transfer-Encoding: chunked". BTW...the streamed files are anywhere from 8MB to 300MB

Here is my pertinent code:

HttpResponseMessage response = null;
try
{
    HttpClient httpClient = new HttpClient
    {
        Timeout = TimeSpan.FromSeconds(60)
    };
    httpClient.DefaultRequestHeaders.Add("Accept", "multipart/related; type="application/dicom"");
    response = await httpClient.GetAsync(uri);
    if (response.StatusCode != HttpStatusCode.OK)
    {
        Console.WriteLine($"Response:[{response}]");
        return false;
    }
}
catch (Exception e)
{
    Console.WriteLine($"Exception:[{e.Message}] | Stack:[{e.StackTrace}] | InnerEx:[{e.InnerException}]");
    return false;
}

Here's the HttpResponseMessage when GetAsync is successful (200/OK):

{
  "Version": {
    "Major": 1,
    "Minor": 1,
    "Build": -1,
    "Revision": -1,
    "MajorRevision": -1,
    "MinorRevision": -1
  },
  "Content": {
    "Headers": [
      {
        "Key": "Content-Type",
        "Value": [ "multipart/related; boundary=Boundary_77_676776408_1611644859244; type="application/dicom"" ]
      }
    ]
  },
  "StatusCode": 200,
  "ReasonPhrase": "OK",
  "Headers": [
    {
      "Key": "Transfer-Encoding",
      "Value": [ "chunked" ]
    },
    {
      "Key": "MIME-Version",
      "Value": [ "1.0" ]
    },
    {
      "Key": "Date",
      "Value": [ "Tue, 26 Jan 2021 07:07:39 GMT" ]
    },
    {
      "Key": "Proxy-Connection",
      "Value": [ "Keep-Alive" ]
    },
    {
      "Key": "Connection",
      "Value": [ "Keep-Alive" ]
    },
    {
      "Key": "Age",
      "Value": [ "0" ]
    }
  ],
  "RequestMessage": {
    "Version": {
      "Major": 2,
      "Minor": 0,
      "Build": -1,
      "Revision": -1,
      "MajorRevision": -1,
      "MinorRevision": -1
    },
    "Content": null,
    "Method": { "Method": "GET" },
    "RequestUri": "http://1.2.3.4:5007/blah/blah1/11/blah2/22/blah3/33",
    "Headers": [
      {
        "Key": "Accept",
        "Value": [ "multipart/related; type="application/dicom"" ]
      }
    ],
    "Properties": {}
  },
  "IsSuccessStatusCode": true
}

Other times there is no response and an exception is thrown:

Exception:[The server returned an invalid or unrecognized response.] | Stack:[ at System.Net.Http.HttpConnection.ThrowInvalidHttpResponse() at System.Net.Http.HttpConnection.ChunkedEncodingReadStream.ReadChunkFromConnectionBuffer(Int32 maxBytesToRead, CancellationTokenRegistration cancellationRegistration) at System.Net.Http.HttpConnection.ChunkedEncodingReadStream.CopyToAsyncCore(Stream destination, CancellationToken cancellationToken) at System.Net.Http.HttpConnection.HttpConnectionResponseContent.SerializeToStreamAsync(Stream stream, TransportContext context, CancellationToken cancellationToken) at System.Net.Http.HttpContent.LoadIntoBufferAsyncCore(Task serializeToStreamTask, MemoryStream tempBuffer) at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts) at myapp.GetBlahAsync(Uri uri, String newFileName) in C:lahSvc.cs:line 97] | InnerEx:[]

question from:https://stackoverflow.com/questions/65904979/c-sharp-httpclient-getasync-exception-the-server-returned-an-invalid-or-unrecog

Answer 1

is because you need deserialize response

   HttpResponseMessage response = null;
try
{
    HttpClient httpClient = new HttpClient {
        Timeout = TimeSpan.FromSeconds(60)
    };
    httpClient.DefaultRequestHeaders.Add("Accept", "multipart/related; type="application/dicom"");
    response = await httpClient.GetAsync(uri);
    if (response.IsSuccessStatusCode)
    {

        var responseData = await response.Content.ReadAsStringAsync();
        var options = new JsonSerializerOptions() { PropertyNameCaseInsensitive = true };
        var result = JsonSerializer.Deserialize<Root>(responseData, options);

        Console.WriteLine($"Response:[{result }]");
        return result;
    }
}
catch (Exception e)
{
    Console.WriteLine($"Exception:[{e.Message}] | Stack:[{e.StackTrace}] | InnerEx:[{e.InnerException}]");
    return false;
}

for convert your json to c# class use this site Json to c# class

  // Root myDeserializedClass = JsonConvert.DeserializeObject<Root>(myJsonResponse); 
        public class Version    {
            public int Major { get; set; } 
            public int Minor { get; set; } 
            public int Build { get; set; } 
            public int Revision { get; set; } 
            public int MajorRevision { get; set; } 
            public int MinorRevision { get; set; } 
        }
    
        public class Header    {
            public string Key { get; set; } 
            public List<string> Value { get; set; } 
        }
    
        public class Content    {
            public List<Header> Headers { get; set; } 
        }
    
        public class Method    {
            public string Method { get; set; } 
        }
    
        public class Properties    {
        }
    
        public class RequestMessage    {
            public Version Version { get; set; } 
            public object Content { get; set; } 
            public Method Method { get; set; } 
            public string RequestUri { get; set; } 
            public List<Header> Headers { get; set; } 
            public Properties Properties { get; set; } 
        }
    
        public class Root    {
            public Version Version { get; set; } 
            public Content Content { get; set; } 
            public int StatusCode { get; set; } 
            public string ReasonPhrase { get; set; } 
            public List<Header> Headers { get; set; } 
            public RequestMessage RequestMessage { get; set; } 
            public bool IsSuccessStatusCode { get; set; } 
        }

or in visual studio in Edit-->Paste Special-->Paste JSON As Classes