Decoding a response c#

Question

I'm developing some API for testing, and I have a problem when I make a webrequest and especially when i retrieve the webresponse. I use this code:

string request = HttpPost("http://iunlocker.net/check_imei.php", "ime_i=013270000134001");

  public static string HttpPost(string URI, string Parameters)
        {
            try
            {
            System.Net.WebRequest req = System.Net.WebRequest.Create(URI);
            req.ContentType = "application/x-www-form-urlencoded";
            req.Method = "POST"; 
            byte[] bytes = System.Text.Encoding.ASCII.GetBytes(Parameters);
            req.ContentLength = bytes.Length;
            System.IO.Stream os = req.GetRequestStream();
            os.Write(bytes, 0, bytes.Length);
            os.Close();

            System.Net.WebResponse resp= req.GetResponse();

            if (resp == null) return null;
            System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
            return sr.ReadToEnd().Trim();
            }
            catch (Exception ex) { }
            return null;    
        }

The website in the call is an example, because with this and with other websites I can't retrieve the result correctly. I receive an exception "Error 403"

Can anyone maybe help me by telling what I may be doing wrong?

I thought the problem was on encoding/decoding -- in fact using Fiddler it asks me if I want to decode before see the text -- but with another website, used for examples, I receive the same message from Fiddler but I can retrieve the response without a problem.

Thanks in advance.

http://stackoverflow.com/questions/10860732/http-response-filter-cant-decode-the-response-bytes-the-second-time — , Jul 03 '13 at 03:49

Ross Presser · Answer 1 · 2013-07-03T04:04:01.547

HTTP 403 error means "access forbidden". The destination website is refusing to fulfill your request, for reasons of its own.

Given this particular website http://iunlocker.net/, I'm going to hazard a guess that it may be checking the HTTP_REFERER. In other words it's refusing to fulfill your request because it knows it didn't come from a browser that was viewing the form.

[EDIT] After viewing the response from

curl --form ime_i=013270000134001 -i http://iunlocker.net/check_imei.php

I can see that the immediate response is setting a cookie and a redirect.

HTTP/1.1 307 Temporary Redirect
Server: nginx
Date: Wed, 03 Jul 2013 04:00:27 GMT
Content-Type: text/html
Content-Length: 180
Connection: keep-alive
Set-Cookie: PMBC=35e9e4cd3a7f9d50e7f3bb39d43750d1; path=/
Location: http://iunlocker.net/check_imei.php?pmtry=1

<html>
<head><title>307 Temporary Redirect</title></head>
<body bgcolor="white">
<center><h1>307 Temporary Redirect</h1></center>
<hr><center>nginx</center>
</body>
</html>

This site does not want you scraping it; if you wish to defeat this you will have to make use of its cookies.

Thanks for your help,this website is only an example because i often found website with this type of pretection and i m really interested to know how this method works and how retrive data correctly,maybe for increase the security level in my website. — user2544906, Jul 03 '13 at 04:32
Thanks for your help,this website is only an example because i often found website with this type of pretection and i m really interested to know how this method works and how retrive data correctly,maybe for increase the security level in my website.So do i need strictly use cookies?I can learn myself how tu use this but can you maybe help me better?How can i found the value of this cooking without using a browser? — user2544906, Jul 03 '13 at 04:40

score 0 · Answer 2 · answered Jul 03 '13 at 04:40

0

http://en.wikipedia.org/wiki/HTTP_403 - The web server is denying you access to that URL.

Perhaps the IP address you are using, is not allowed to access that resource. Check web server.

answered Jul 03 '13 at 04:40

Shafiq Abbas

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No problem with my Ip because making an httrequest with a browser i receive the response without problems.It s not the first i see this type of protection and i would understand better how it works – user2544906 Jul 03 '13 at 04:45

Decoding a response c#

2 Answers2