Send Web request working with rest client app, but not working with c#

Question

I am sending a post request to an api with c# webrequest and httpClient but always i get an error message from the api which says you posted invalid data in the header , but the point is when i send same data with chrome extension advanced rest client it works fine and i compared both request there is nothing different i have attached both request and my code , can anybody help to figure out what is the problem ,

this is the request from rest client app:

and here is the request from c#

and here is my c# code

 string item = "<?xml version=\"1.0\" encoding=\"UTF - 8\"?>" +
  "<request>" +
  "<Username>admin</Username>" +
  "<Password>" + password + "</Password>" +
  "<password_type>4</password_type>" +
  "</request> ";
var request = (HttpWebRequest)WebRequest.Create("http://192.168.8.1/api/user/login");
request.Method = "POST";
request.Headers["_RequestVerificationToken"]= Token;
request.Headers["Cookie"] = Sess;
byte[] bytes = Encoding.UTF8.GetBytes(item);
request.ContentType = "application/xml;charset=UTF-8";
request.ContentLength = bytes.Length;
Stream streamreq = request.GetRequestStream();
streamreq.Write(bytes, 0, bytes.Length);
streamreq.Close();
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
    var result = reader.ReadToEnd();
}

`and i compared both request there is nothing different` Looking at the screenshots there are multiple things that are different. `SessionID` is different. `_RequestVerificationToken` is different. — mjwills, Aug 21 '17 at 08:33
Which API are you calling (is it https://github.com/arska/e3372/issues/1)? Do they document what `125002` code means? — mjwills, Aug 21 '17 at 08:36
@mjwills sessinid and token is changed per each request, the problem is i am sending a valid session and token id that i get from api , but in c# not returning ok, and the error code says invalid session , it is an api from huawei LTE modems — Younis Qadir, Aug 21 '17 at 08:38
the value of password is a hashed password each time changed due to token ,and this link is what exactly i am using sessInfo to get session and token for each request — Younis Qadir, Aug 21 '17 at 08:41
this is one example of password ZTJkZGZhZGZjZmZlMjk0OGQ4MGZmZTk3NGRjMDE4MWY4NmIyMzcwZjRjNzg0ZjMyNmFjNGE4NmRmZmE4MGI0MA== and generated from Base64Encode(Sha256(username + Base64Encode(Sha256(password)) + Token)); username=admin ,pass=admin — Younis Qadir, Aug 21 '17 at 09:08
Instead of WebRequest etc, you should use something like RestSharp or ReFit etc. — Akash Kava, Aug 28 '17 at 08:10
i used restsharp and got same result, also tried in java also the same, but tested in postman and arc it works . — Younis Qadir, Aug 28 '17 at 08:24
Try __requestverificationtoken? Small caps and two underscores. — Ulf Kristiansen, Aug 28 '17 at 17:24
@ Ulf Kristiansen you saved my life many thanks , i did not expect the problem was that . :) can you post an answer so i can make it correct answer ? — Younis Qadir, Aug 29 '17 at 06:15

score 4 · Accepted Answer · answered Aug 29 '17 at 07:01

4

It looks like __RequestVerificationToken contains two underscores in the left picture, so try this:

request.Headers["__RequestVerificationToken"]= Token;

answered Aug 29 '17 at 07:01

Ulf Kristiansen

1,471
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Ps. In the comments I suggested using small caps as well, but [field names in HTTP headers are case-insensitive](https://stackoverflow.com/a/5259004/1576119), so the extra underscore should do the trick. – Ulf Kristiansen Aug 29 '17 at 07:08

score 1 · Answer 2 · answered Aug 29 '17 at 04:54

The main difference it Saw here was that at the API you are sending

application/xml

but at the C# code you are sending

application/xml;charset=UTF-8;

In your API, the content length is 230 and in the C# the content length is 227, 3 chars less.

Now, It may be a long shot but charsets work differently with every browser and with every language so there might be an issue when you add charset=UTF-8 in your code.

Send your request as follows:

 string item = "<?xml version=\"1.0\" encoding=\"UTF - 8\"?>" +
  "<request>" +
  "<Username>admin</Username>" +
  "<Password>" + password + "</Password>" +
  "<password_type>4</password_type>" +
  "</request> ";
var request = (HttpWebRequest)WebRequest.Create("http://192.168.8.1/api/user/login");
request.Method = "POST";
request.Headers["_RequestVerificationToken"]= Token;
request.Headers["Cookie"] = Sess;
byte[] bytes = Encoding.UTF8.GetBytes(item);
request.ContentType = "application/xml";
request.ContentLength = bytes.Length;
Stream streamreq = request.GetRequestStream();
streamreq.Write(bytes, 0, bytes.Length);
streamreq.Close();
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
    var result = reader.ReadToEnd();
}

thanks a lot the problem was using request verification token with two underscore . — Younis Qadir, Aug 29 '17 at 06:16

Send Web request working with rest client app, but not working with c#

2 Answers2