Sending Multipart form data from windows phone to web api - asp.net-mvc-4

Question

Hi I want to send(post/put) some data(containing string, int and Stream) from windows phone 8.1 using HttpClient to web api. what is the best way to do that.
public async void Put(string uri)
{
var httpClient = new System.Net.Http.HttpClient();
MultipartFormDataContent content = new MultipartFormDataContent();
var stringContent = new StringContent("FirstName=MUH&LastName=Test", Encoding.UTF8, "multipart/form-data");
var test = new StreamContent(new MemoryStream());
content.Add(test);
content.Add(stringContent);
var message = await httpClient.PutAsync(url+"/UpdateTest", content);
message.EnsureSuccessStatusCode();
string content1 = await message.Content.ReadAsStringAsync();
}
api method in my mvc app
[AllowAnonymous]
[Route("~/api/account/UpdateTest")]
[HttpPut]
public async Task<object> UpdateTest()
{
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}
try
{
var requestParts = await Request.Content.ReadAsMultipartAsync();
foreach (var part in requestParts.Contents)
{
//part is always StreamContent
var test = await part.ReadAsStreamAsync();
var test1 = await part.ReadAsStringAsync();
}
}
catch (Exception ex)
{ }
}
In my windows phone project I have passed 2 HttpContent, one is StreamContent where as other is StringContent. but in my web api put method both are StreamContent I do't know why.
and other problem is I have to parse the string key value in StingContnet. My question is what is the best way of sending/receiving multipart form data from windows phone 8.1 to web api,
Thanks

Answer 1

Following is an example(change this accordingly to your scenario):
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(baseAddress);
HttpRequestMessage request = new HttpRequestMessage();
MultipartFormDataContent mfdc = new MultipartFormDataContent();
mfdc.Add(new StringContent("Michael"), name: "FirstName");
mfdc.Add(new StringContent("Jordan"), name: "LastName");
mfdc.Add(new StreamContent(content: new MemoryStream(Encoding.UTF8.GetBytes("This is from a file"))),
name: "Data",
fileName: "File1.txt");
HttpResponseMessage response = await client.PostAsync(baseAddress + "/api/values", mfdc);
public async Task Post()
{
if (!Request.Content.IsMimeMultipartContent())
{
throw new HttpResponseException(HttpStatusCode.BadRequest);
}
MultipartFormDataStreamProvider prov = await Request.Content.ReadAsMultipartAsync<MultipartFormDataStreamProvider>(new MultipartFormDataStreamProvider(#"C:\uploadedfiles"));
// example of how you can read the form data
string firstName = prov.FormData["FirstName"];
// Get list of all files that have been uploaded and stored in the above provided root folder
Collection<MultipartFileData> files = prov.FileData;
}
Following is how request looks like in Fiddler tool:
POST http://localhost:9095/api/values HTTP/1.1
Content-Type: multipart/form-data; boundary="7560a854-a71a-4e55-9571-5c2de520f45f"
Host: kirandesktop:9095
Content-Length: 474
Expect: 100-continue
Connection: Keep-Alive
--7560a854-a71a-4e55-9571-5c2de520f45f
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=FirstName
Michael
--7560a854-a71a-4e55-9571-5c2de520f45f
Content-Type: text/plain; charset=utf-8
Content-Disposition: form-data; name=LastName
Jordan
--7560a854-a71a-4e55-9571-5c2de520f45f
Content-Disposition: form-data; name=Data; filename=File1.txt; filename*=utf-8''File1.txt
This is from a file
--7560a854-a71a-4e55-9571-5c2de520f45f--
Also note that you can read the StreamContent anyway you want...in the following examples, I am simulating a request's body stream and reading it as a simple string or deserializing into an object of type Person.
StreamContent requestStream = new StreamContent(new MemoryStream(Encoding.UTF8.GetBytes("Hello World!")));
string data = await requestStream.ReadAsStringAsync();
//---------------------
StreamContent requestStream = new StreamContent(new MemoryStream(Encoding.UTF8.GetBytes("{ \"FirstName\" : \"Michael\" }")));
requestStream.Headers.ContentType = new MediaTypeHeaderValue("application/json");
Person person = await requestStream.ReadAsAsync<Person>();

Answer 2

I use a custom media type formatter that's based on the code in this article.
ASP.NET WebApi: MultipartDataMediaFormatter
One of the advantages over the MultipartFormDataStreamProvider is that I don't need to specify a folder to save the file data, so I can inspect the contents in memory. You might not want to do this with huge files though. There's alot a github repo for it too if you want to look at the code. Also, I get strongly typed objects for file and form data