How to upload image to server (using POST) which return json in Windows Phone 8.1 RT? - json

Question

I am making an app which can upload image to a server (the server works well), and I use this method to upload my image to it, but when I get the respond from the result, it return a null string, can you explain for me what did I do wrong.
I followed this method: How to upload file to server with HTTP POST multipart/form-data
HttpClient httpClient = new HttpClient();
MultipartFormDataContent form = new MultipartFormDataContent();
form.Headers.ContentType = new MediaTypeHeaderValue("multipart/form-data");
byte[] bytes = await Converter.GetBytesAsync(storageFile);
form.Add(new ByteArrayContent(bytes, 0, bytes.Count()), "\"upload-file\"", "\"test.jpg\"");
HttpResponseMessage response = await httpClient.PostAsync("my-url", form);
response.EnsureSuccessStatusCode();
httpClient.Dispose();
string sd = response.Content.ReadAsStringAsync().Result;
Debug.WriteLine("res: " + sd); // this return a null string
The request return like this:
--a81d2efe-5f2e-4f84-83b9-261329bee20b
Content-Disposition: form-data; name="upload-file"; filename="test.jpg"; filename*=utf-8''%22test.jpg%22
����Ivg?�aEQ�.�����(��9%�=��>�C�~/�QG$�֨������(�`������QE��Z��
Can you help me please!
P/s: Here is my convert method
public static async Task<byte[]> GetBytesAsync(StorageFile file)
{
byte[] fileBytes = null;
if (file == null) return null;
using (var stream = await file.OpenReadAsync())
{
fileBytes = new byte[stream.Size];
using (var reader = new DataReader(stream))
{
await reader.LoadAsync((uint)stream.Size);
reader.ReadBytes(fileBytes);
}
}
return fileBytes;
}

Answer 1

This might help
private async Task<string> UploadImage(StorageFile file)
{
HttpClient client = new HttpClient();
MultipartFormDataContent form = new MultipartFormDataContent();
HttpContent content = new StringContent("fileToUpload");
form.Add(content, "fileToUpload");
var stream = await file.OpenStreamForReadAsync();
content = new StreamContent(stream);
content.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
{
Name = "fileToUpload",
FileName = file.Name
};
form.Add(content);
var response = await client.PostAsync("my-url", form);
return response.Content.ReadAsStringAsync().Result;
}

Answer 2

Use ByteArrayContent instead of StringContent. That Should work.
And if you are expecting a stream-response you should use ReadAsStreamAsync instaed of ReadAsStringAsync.