Why is the response of REST API not in JSON format in my code, but is in the correct format with Google extension "restman"?

Question

Why is the response of REST API is not in JSON format in my code? But with Google extension "RestMan" it is in correct format. My code is like this:

using (WebClient client = new WebClient())
{
  byte[] response = client.UploadValues("http://personnel.fasau.ac.ir:8085/PersonApi/api/Token/Login", new NameValueCollection()
  {
    {"Username", "name"},
    {"Password", "pass"}
  });
string result = System.Text.Encoding.UTF8.GetString(response);
}

The response I get is like this:

\u001f�\b\0\0\0\0\0\u0004\05��n�P\u0010�_�b�D\\�#�3�`��1\u001c\u000e\aÎ�[.\a�\b\u000e6Q\u0017ݴY�=��*+}\u0018��Lq��f4��#���0$�i�<6�a7f�>ߕ�#�;�I���M�kN�q0՞�\u0012��\\�jy�%s]�\u001fD\\X�c�Oa�6�=,\v�À(\u000e�ׁbՖ[�إ+ª�K�銕*�A\u001b�t�/��+Z�pPe\u0003\t�\u0005h �w\u0006�:TX��I�e��a��JR;\u000e�C%Yc\"/\u0093T�*�\u0002Jr��ҥ2@%��lv2�X�\u0001R1�8䴓��Ǎ�8\u0001�]�ru�hD��\u000fv�`ċ.��f�Gm�� �u=����\u001f�\u0004#N��\f�!�z\u001b\u0017�\u0001�uCa��\\\a�\u0016��B\u0015���it�\u001f��K7\u0019�\r%\u0017�\u0012�\u0006����Ln�\r}��\u0011\a��G��iબ��0����\u0004C\u0001�p��\u0004�\u0016�<Z�.�}v]���\u001e \u0014*������\u0012>��u�x��J��6$�������ML�m��T�7�S�3\u0019��>�\u001a`<��\u00193�R\u0018\u0014�������_���2���o����\\_����\a���=�X\u000e�1\u0003�z_㴡7[��?_���?n����u�/\u007f\u0001b�Q�S\u0002\0\0

The response body of "RestMan" is like this (in correct format):

{
    "Valid": true,
    "Token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1bmlxdWVfbmFtZSI6Im56RDhteWJaUkVkV2Fsdmppa2hCM0Y5RHdnQWMyRm5UczZja3ZMUjNiUkxFaTUwUGNrYUt3VTdoZHpKbS9KM1FlYkR0ZDhkZUlSZjBFMHdHcUJJRE01VVRld1JDS3pZOWU0akxKMzhBSmY3MVBQaU9RdG50YXNzYlV0Q0pRK2dCUlJ1a01oQTBUKzhFWnkvenNkQ0NUbTYzR01GTFR2S2NwOGtLUVh0ZmJ1WT0iLCJEaXNwbGF5TmFtZSI6IlciLCJuYmYiOjE2MDk2ODI3NDksImV4cCI6MTYwOTY5MzU0OSwiaWF0IjoxNjA5NjgyNzQ5LCJpc3MiOiJCcHRzb2Z0LmNvbSIsImF1ZCI6IkJwdHNvZnQuY29tIn0.4J0h30Gd1RzWl3tBulGWEQwcQW_PnTV0VTDFAb8S-vg",
    "FullName": "کاربر وب سرویس",
    "Photo": null,
    "ErrorTitle": "دانشگاه فسا"
}

Answer 1

Try setting an accept header,

client.Headers.Add("Accept", "application/json");

Update: It is also possible that the response in compressed using Gzip compression. Use a helper function to decompress the string first and then use a JSON serializer to serialize it.

A helper function I use to decompress Gzip in my code,

using System;
using System.IO;
using System.IO.Compression;
using System.Text;

public string DecompressString(string s, Encoding encoding)
{
  // obtaining bytes from the string in the below step
  // In my case, it was a base 64 string
  // If not use encoding.GetBytes() function
  var bytes = Convert.FromBase64String(s); 

  using (var msi = new MemoryStream(bytes))
  using (var mso = new MemoryStream())
  {
    using (var gs = new GZipStream(msi, CompressionMode.Decompress))
    {
      gs.CopyTo(mso);
    }
    return encoding.GetString(mso.ToArray());
  }
}

var originalRes = // call your function here
var decompressedRes = helper.DecompressGzipString(originalRes, Encoding.UTF8);