How to migrate HttpWebRequest for Multipart file to HttpClient - httprequest

Question

I am working on an ASP.Net Core 2.0 API and one of the services I need to create is to upload files to a 3rd party site via their API. The examples for their API uses HttpWebRequest and I need to migrate this to use HttpClient.
Below is the relevant portion of their example code for a file upload.
var url = "https://localhost:44636/api/uploads";
var request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "POST";
var credentialCache = new CredentialCache();
var username = "APIUser";
var password = "APIUserPassword";
credentialCache.Add(new Uri(url), "Basic", new NetworkCredential(username, password));
request.Credentials = credentialCache;
request.PreAuthenticate = true;
request.Accept = "application/json";
request.AllowWriteStreamBuffering = true;
var uploadFileRequest = new UploadFileRequest();
uploadFileRequest.environment = "DEV";
uploadFileRequest.filename = filename;
uploadFileRequest.multipartFile = File.ReadAllText(filepath + #"\" + filename, UTF8Encoding.UTF8);
var boundaryText = "--ACI-XFER";
var bodyText = new StringBuilder();
bodyText.Append("--" + boundaryText + "\r\n");
bodyText.Append("Content-Disposition: form-data; name=\"filename\"" + "\r\n\r\n");
bodyText.Append(uploadFileRequest.filename + "\r\n");
bodyText.Append("--" + boundaryText + "\r\n");
bodyText.Append("Content-Disposition: form-data; name=\"environment\"" + "\r\n\r\n");
bodyText.Append(uploadFileRequest.environment + "\r\n");
bodyText.Append("--" + boundaryText + "\r\n");
bodyText.Append("Content-Disposition: form-data; name=\"multipartFile\"; filename=\"" +
uploadFileRequest.filename + "\"" + "\r\n");
bodyText.Append("Content-Type: text/plain" + "\r\n\r\n");
bodyText.Append(uploadFileRequest.multipartFile + "\r\n");
bodyText.Append("--" + boundaryText + "--");
var bodyBytes = UTF8Encoding.UTF8.GetBytes(bodyText.ToString());
request.ContentType = "multipart/form-data; boundary=" + boundaryText;
request.ContentLength = bodyBytes.Length;
var requestStream = request.GetRequestStream();
requestStream.Write(bodyBytes, 0, bodyBytes.Length);
requestStream.Close();
using (var webResponse = (HttpWebResponse)request.GetResponse())
{
if (webResponse.StatusCode == HttpStatusCode.OK)
{
using (var responseReader = new StreamReader(webResponse.GetResponseStream()))
{
var responseText = responseReader.ReadToEnd();
if (logger.IsDebugEnabled)
{
logger.Debug("HttpWebResponse: \r\n" + responseText + "\r\n");
}
}
return true;
}
else
{
if (logger.IsErrorEnabled)
{
logger.Error("HttpWebResponse Error UploadProcessFile(), Server: " +
webResponse.Server + ", StatusCode: " + webResponse.StatusCode + ", StatusDescription: " +
webResponse.StatusDescription);
}
return false;
}
}
}
In ASP.NET Core 2.0 using the HttpClient, I have come up with this code, but when I try to upload the file, I get a 400 error stating "Please select a file to upload"
boundryText = "ACI-XFER"
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("https://localhost:44636");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
string relativeUrl = "api/uploads";
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, relativeUrl);
var byteArray = new UTF8Encoding().GetBytes("APIUser:APIUserPassword");
request.Headers.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(byteArray));
using (var content = new MultipartFormDataContent(boundryText))
{
content.Add(new StringContent(uploadFileRequestDto.FileName + "\r\n"), "filename");
content.Add(new StringContent(uploadFileRequestDto.PdxEnvironment + "\r\n"), "environment");
Encoding encNoBoM = new UTF8Encoding(false);
content.Add(new StringContent(uploadFileRequestDto.TextFile + "\"" + "\r\n", encNoBoM, "text/plain"), "multipartfile", uploadFileRequestDto.FileName);
request.Content = content;
response = await client.SendAsync(request);
}
}
if (response.IsSuccessStatusCode)
{
string jsonResult = response.Content.ReadAsStringAsync().Result;
uploadFileResponseDto = (uploadFileResponseDto)JsonConvert.DeserializeObject(jsonResult);
uploadFileResponseDto.Success = true;
uploadFileResponseDto.StatusCode = 200;
return uploadFileResponseDto;
}
_logger.LogError("File upload for Id [{ID}] failed. Reason: {ReasonPhrase}", uploadFileRequestDto.Id, response.ReasonPhrase);
uploadFileResponseDto.Success = false;
uploadFileResponseDto.Reason = string.Format($"Status Code: [{response.StatusCode}], Reason: [{response.ReasonPhrase}]");
uploadFileResponseDto.StatusCode = 500;
return uploadFileResponseDto;
Here is the request as it looks in Fiddler;
**Headers**
POST /api/uploads HTTP/1.1
Connection: Keep-Alive
Content-Type: multipart/form-data; boundary="--ACI-XFER"
Accept: application/json
Authorization: Basic XXXXXXXXXXXXXXXXXXXXXX
x-ms-request-root-id: 4f112b3-4c33c20cb1d76dec
x-ms-request-id: |4f112b3-4c33c20cb1d76dec.1.
Request-Id: |4f112b3-4c33c20cb1d76dec.1.1.
Content-Length: 325354
Host: localhost:44636
Content
----ACI-XFER
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=filename
test1upload.txt
----ACI-XFER
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=environment
DEV
----ACI-XFER
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=multipartfile; filename=test1upload.txt; filename*=utf-8''test1upload.txt
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I feel that the problem is coming from how I am doing this line in my code, which sets up the text file content to upload;
content.Add(new StringContent(uploadFileRequestDto.TextFile + "\"" + "\r\n", encNoBoM, "text/plain"), "multipartfile", uploadFileRequestDto.FileName);
I had first tried it like this, without the added and slashes and carriage return line feed, but got the same error.
content.Add(new StringContent(uploadFileRequestDto.TextFile, encNoBoM, "text/plain"), "multipartfile", uploadFileRequestDto.FileName);
But I am having difficulty finding a good example of how to do this.
Any ideas?