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Getting 400 exception in HttpWebRequest Call

I am using Postman to get the response from rest end point, and if I pass wrong data I am getting 400 exception which is very correct as per the logic.
But if I try to call the same web request from C# code(with same wrong parameter), I am getting exception but not the same as I am getting in Postman tool.
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
var httpWebRequest = (HttpWebRequest)WebRequest.Create("https://apiurl");
httpWebRequest.ContentType = "application/json";
httpWebRequest.Headers.Add("Authorization", "Bearer " + token);
httpWebRequest.Method = "POST";
httpWebRequest.UserAgent = ".Net application";
using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
string json = JsonConvert.SerializeObject(obj);//obj is parameter
streamWriter.Write(json);
}
try
{
HttpWebResponse httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var result = streamReader.ReadToEnd();
}
}
catch (WebException e)
{
}
Can I know why I am getting errors differently from postman and C# code
Regards
Anand

Added below code in the exception block and it gave me the same response as Postman
catch(WebException ex)
{
string message = ex.Message;
WebResponse errorResponse = ex.Response;
if (errorResponse != null)
{
using (Stream responseStream = errorResponse.GetResponseStream())
{
StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("utf-8"));
message = reader.ReadToEnd();
}
}
}

C# WebRequest - HTTP: 403 Forbidden ('_xsrf' argument missing from POST)

I'm stucked here at getting a WebResponse from HTTPWebRequest.
The WebRequest.GetResponse() Method throws a WebException
("500 Internal Server Error"). When i read the returned HTML it says:
HTTP 403: Forbidden ('_xsrf' argument missing from POST)
Anyone knows this Error or knows what Im doing wrong?
(Im trying to log in to a Website using POST)
EDIT:
My sourcecode:
private String GetLoginCookies(String pHTTPurl, String pUserIDwithFormID, String pPasswordWithFormID)
{
String loginPageUrl = pHTTPurl;
CookieContainer cookieContainer = new CookieContainer();
var Request = (HttpWebRequest)WebRequest.Create(loginPageUrl);
Request.CookieContainer = cookieContainer;
Request.Method = "GET";
WebResponse Response = Request.GetResponse();
HttpWebResponse HttpResponse = Response as HttpWebResponse;
CookieCollection cookies = null;
if (HttpResponse != null)
{
//Cookies die benötigt werden um den Loginvorgang abzuschließen
cookies = HttpResponse.Cookies;
}
string formParams = string.Format(pUserIDwithFormID + "&" + pPasswordWithFormID);
Request = (HttpWebRequest)WebRequest.Create(loginPageUrl);
Request.CookieContainer = cookieContainer;
Request.UserAgent = "I am not a Bot! Ok maybe..";
WebResponse resp = null;
Request.ContentType = "application/x-www-form-urlencoded";
Request.Method = "POST";
byte[] bytes = Encoding.ASCII.GetBytes(formParams);
Request.ContentLength = bytes.Length;
using (Stream os = Request.GetRequestStream())
{
os.Write(bytes, 0, bytes.Length);
}
try
{
resp = Request.GetResponse();
using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
{
String TestResponse = sr.ReadToEnd();
}
}
catch (WebException WE)
{
DebugConsole.AppendText("HTTP Error:" + WE.Message + Environment.NewLine);
String HTML = new StreamReader(WE.Response.GetResponseStream()).ReadToEnd();
DebugConsole.AppendText(HTML);
return null;
}
String cookieHeader = resp.Headers["Set-cookie"];
if (String.IsNullOrEmpty(cookieHeader))
return null;
else
return cookieHeader;
}

This is actually because the web method requires anti csrf (cross site request forgery, more info here: https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)) validation parameter. What you can do, is to append the csrf value to the request header:
postHeaders.Add("X-CSRFToken", CSRF);
Maybe you can paste your source code here if you need any help with that, so we can look after it

OK! Solution found!
After getting the response of the Log-In site, search in the "Set-cookie" Header for _xsrf. This is the Token you have to put in the header of the next POST request.

Getting content from httpwebresponse exception

My remote server is throwing a web exception as bad request. But I know there is more information included in the error than what I get. If I look at the details from the exception it does not list the actual content of the response. I can see the content-type, content-length and content-encoding only. If I run this same message through another library (such as restsharp) I will see detailed exception information from the remote server. How can I get more details from the response since I know the remote server is sending them?
static string getXMLString(string xmlContent, string url)
{
//string Url;
string sResult;
//Url = ConfigurationManager.AppSettings["UserURl"] + url;
var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);
httpWebRequest.ContentType = "application/xml";
httpWebRequest.Method = "POST";
using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
streamWriter.Write(xmlContent);
streamWriter.Flush();
streamWriter.Close();
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var result = streamReader.ReadToEnd();
sResult = result;
}
}
return sResult;
}

EDIT : Have you tried with a simple try-catch to see if you can get more details ?
try
{
var response = (HttpWebResponse)(request.GetResponse());
}
catch(Exception ex)
{
var response = (HttpWebResponse)ex.Response;
}
In my recherches in an answer for you, I noticed that in code there was something about encoding, that you didn't specified. Look here for exemple with such code.
var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(response.GetResponseStream(), encoding))
{
string responseText = reader.ReadToEnd();
}
Or here, in the doc, also.
// Creates an HttpWebRequest with the specified URL.
HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(url);
// Sends the HttpWebRequest and waits for the response.
HttpWebResponse myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse();
// Gets the stream associated with the response.
Stream receiveStream = myHttpWebResponse.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
// Pipes the stream to a higher level stream reader with the required encoding format.
StreamReader readStream = new StreamReader( receiveStream, encode );
Console.WriteLine("\r\nResponse stream received.");
Have you tried with such ?

Testing multiple parameters web api c# - fiddler

I need help.
I have a method: PostCustomer
HttpResponseMessage PostCustomer([FromBody] CustomerRec Logs, [FromBody] Customer customer)
Now my problem is how will I able to test this through fiddler
I know I need to call for example:
"//api/customer/PostCustomer"
But how will I pass parameters on this?
I'm testing this using fiddler.

I'm not sure if you are asking how to build the url request (passing the parameters for your method through url)
If that's it, it should be like this
api/customer/PostCustomer/?FirstParameter=Example&SecondParemeter=Example2
If you mean the request itself
string postData = string.Format("?FirstParameter=" + txt_First.Text + "&SecondParemeter=" + txt_Last.Text);
byte[] data = Encoding.UTF8.GetBytes(postData);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("..../api/customer/PostCustomer"/" + postData);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.Accept = "application/json";
request.ContentLength = data.Length;
using (Stream requestStream = request.GetRequestStream())
{
requestStream.Write(data, 0, data.Length);
}
try
{
using (WebResponse response = request.GetResponse())
{
var responseValue = string.Empty;
// grab the response
using (var responseStream = response.GetResponseStream())
{
using (var reader = new StreamReader(responseStream))
{
responseValue = reader.ReadToEnd(); // read the full response
}
}
if (responseValue != "")
{
//Do something here if response is not empty
}
}
}
catch (WebException ex)
{
// Handle error
}
PS: Can't comment on post because it asks for 50+ reputation...

HttpWebRequest get 404 page only when using POST mode

First of all: I know this has been asked over 100 times, but most of these questions were eigher caused by timeout problems, by incorrect Url or by foregetting to close a stream (and belive me, I tried ALL the samples and none of them worked).
So, now to my question: in my Windows Phone app I'm using the HttpWebRequest to POST some data to a php web service. That service should then save the data in some directories, but to simplify it, at the moment, it only echos "hello".
But when I use the following code, I always get a 404 complete with an apache 404 html document. Therefor I think I can exclude the possibility of a timeout. It seems like the request reaches the server, but for some reason, a 404 is returned. But what really makes me be surprised is, if I use a get request, everything works fine. So here is my code:
HttpWebRequest webRequest = (HttpWebRequest)HttpWebRequest.CreateHttp(server + "getfeaturedpicture.php?randomparameter="+ Environment.TickCount);
webRequest.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0";
webRequest.Method = "POST";
webRequest.ContentType = "text/plain; charset=utf-8";
StreamWriter writer = new StreamWriter(await Task.Factory.FromAsync<Stream>(webRequest.BeginGetRequestStream, webRequest.EndGetRequestStream, null));
writer.Write(Encoding.UTF8.GetBytes("filter=" + Uri.EscapeDataString(filterML)));
writer.Close();
webRequest.BeginGetResponse(new AsyncCallback((res) =>
{
string strg = getResponseString(res);
Stator.mainPage.Dispatcher.BeginInvoke(() => { MessageBox.Show(strg); });
}), webRequest);
Although I don't think this is the reason, here's the source of getResponseString:
public static string getResponseString(IAsyncResult asyncResult)
{
HttpWebRequest webRequest = (HttpWebRequest)asyncResult.AsyncState;
HttpWebResponse webResponse;
try
{
webResponse = (HttpWebResponse)webRequest.EndGetResponse(asyncResult);
}
catch (WebException ex)
{
webResponse = ex.Response as HttpWebResponse;
}
MemoryStream tempStream = new MemoryStream();
webResponse.GetResponseStream().CopyTo(tempStream);
tempStream.Position = 0;
webResponse.Close();
return new StreamReader(tempStream).ReadToEnd();
}

This is tested code work fine in Post method with some body. May this gives you an idea.
public void testSend()
{
try
{
string url = "abc.com";
string str = "test";
HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
req.Method = "POST";
req.ContentType = "text/plain; charset=utf-8";
req.BeginGetRequestStream(SendRequest, req);
}
catch (WebException)
{
}
}
//Get Response and write body
private void SendRequest(IAsyncResult asyncResult)
{
string str = "test";
string Data = "data=" + str;
HttpWebRequest req= (HttpWebRequest)asyncResult.AsyncState;
byte[] postBytes = Encoding.UTF8.GetBytes(Data);
req.ContentType = "application/x-www-form-urlencoded";
req.ContentLength = postBytes.Length;
Stream requestStream = req.GetRequestStream();
requestStream.Write(postBytes, 0, postBytes.Length);
requestStream.Close();
request.BeginGetResponse(SendResponse, req);
}
//Get Response string
private void SendResponse(IAsyncResult asyncResult)
{
try
{
MemoryStream ms;
HttpWebRequest request = (HttpWebRequest)asyncResult.AsyncState;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asyncResult);
HttpWebResponse httpResponse = (HttpWebResponse)response;
string _responestring = string.Empty;
using (Stream data = response.GetResponseStream())
using (var reader = new StreamReader(data))
{
_responestring = reader.ReadToEnd();
}
}
catch (WebException)
{
}
}

I would suggest you to use RestSharp for your POST requests in windows phone. I am making an app for a startup and i faced lots of problems while using a similar code as yours. heres an example of a post request using RestSharp. You see, instead of using 3 functions it can be done in a more concise form. Also the response can be handled efficiently. You can get RestSharp from Nuget.
RestRequest request = new RestRequest("your url", Method.POST);
request.AddParameter("key", value);
RestClient restClient = new RestClient();
restClient.ExecuteAsync(request, (response) =>
{
if (response.StatusCode == HttpStatusCode.OK)
{
StoryBoard2.Begin();
string result = response.Content;
if (result.Equals("success"))
message.Text = "Review submitted successfully!";
else
message.Text = "Review could not be submitted.";
indicator.IsRunning = false;
}
else
{
StoryBoard2.Begin();
message.Text = "Review could not be submitted.";
}
});

It turned out the problem was on the server-side: it tried it on the server of a friend and it worked fine, there. I'll contact the support of the hoster and provide details as soon as I get a response.