Can not Access a URL using Webrequest

Question

I am trying to get access a URL using .Net but when I run my Program I get the Error The remote server returned an error: (403) Forbidden. Now, the issue is if I click the link http://thisIsMyUR, and enter the user name and password as in the below code. It totally works. I am not able to understand why this exception is coming? Please refer the code below.

Side Note: I am using this sample function below to fire Build of my project in Jenkins Server.

string url = "http://thisIsMyURL";
WebRequest webRequest = WebRequest.Create(url);
webRequest.Credentials = new NetworkCredential("admin", "pass");
WebResponse response = webRequest.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string responseText = reader.ReadToEnd();

Your code has some errors that would prevent it from even compiling. — Bradley Uffner
– Bradley Uffner, Commented Jan 3, 2018 at 16:18
Try setting Request.UseDefaultCredentials to false, and Request.PreAuthenticate to true before making the request. — Bradley Uffner
– Bradley Uffner, Commented Jan 3, 2018 at 16:23

HaroldH · Accepted Answer · 2018-01-03 16:39:20Z

1

Other than what was recommended by Bradley Uffner in the comments, you can try to provide an actual user agent during the request. I have seen certain servers which would not respond to requests without that header for some odd perceived security reason.

EDIT: as requested, i'll update with some more information.

Some servers may choose to ignore requests, giving some error code (or closing connection) when certain conditions are not met. A good way of checking if that is the case, is to actually send all the standard headers sent by your average web browser in the request. The "User agent" is one of those headers, and this example adds it to your request:

string url = "http://thisIsMyURL";
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);
webRequest.UserAgent = "USER AGENT VALUE";
HttpWebRequest.Credentials = new NetworkCredential("admin", "pass");
WebResponse response = webRequest.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string responseText = reader.ReadToEnd();

The cast to HttpWebRequest is required so you have access to the UserAgent header field. Other standard HTTP fields can be accessed this way.

You can check which headers are sent by your browser of choice by inspecting its requests using the browser developer tools (usually Right click on webpage -> Inspect elements -> Network).

edited Jan 3, 2018 at 16:39

answered Jan 3, 2018 at 16:25

HaroldH

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5 Comments

Abhishek Kumar Over a year ago

Could you please elaborate your answer.

HaroldH Over a year ago

I added some extra information which may clarify what I talked about.

Abhishek Kumar Over a year ago

Still does not work, i used Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Win64; x64; Trident/4.0) as useragent string

HaroldH Over a year ago

You can try using other parameters. It is a possibility it's requesting any of them.

Abhishek Kumar Over a year ago

It is so ridiculous, I tried with powershell and it works amazingly, I even gave Admin rights to the executable. I can not understand.

Abhishek Kumar · Accepted Answer · 2018-01-04 10:00:41Z

0

I figured it out with the help of some articles. A basic authentication needs to be added. Below is a sample.

 var userName = "admin;"
 var password = "password";
 var encodedAuthentication = Convert.ToBase64String(Encoding.GetEncoding("ISO-8859-1").GetBytes(userName + ":" + password));
 webRequest.Headers.Add("Authorization", "Basic " + encodedAuthentication);

answered Jan 4, 2018 at 10:00

Abhishek Kumar

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