?
Solved

internal server error 500 when using http post containing %0A%3C

Posted on 2008-06-19
2
Medium Priority
?
1,185 Views
Last Modified: 2013-12-16
Hi

I am trying to perform an HTTP POST to a website. Every time i do the POST i get a response of 500. Internal server error.

I have found out that the reason i am getting the error is because the POST contains the string:

%0A%3C

This is a line feed and a < sign.

For some reason i am unable to post this data when it is a requirement for me. If i use %0A%3E (which is line feed and > sign) it works.

Does anyone know why this would happen?

Any help would be appreciated. I have attached the code that i am using.

I am running Microsoft Visual Studio 2005. .Net 2.0 Service Pack 1, Windows XP and IIS 5.1

(i tried it on server 2003 with iis 6.0 and had the same error)

Apyreal
static void Main(string[] args)
        {
           string query = "?%0A%3Chey";
            string a = HTTPCallback("url", query, "POST");
            Console.WriteLine(a);
            Console.ReadLine();
        }
 
        // simple generic http get/post request function
        static string HTTPCallback(string uri, string query, string method)
        {
            string output = string.Empty;
            try
            {
                // request
                WebRequest request;
                // do a POST if requested, otherwise default to a GET
                if (method.ToUpper() == "POST")
                {
                    request = WebRequest.Create(uri);
                    request.Method = "POST";
                    byte[] buffer = Encoding.UTF8.GetBytes(query);
                    request.ContentType = "application/x-www-form-urlencoded";
                    request.ContentLength = buffer.Length;
                    // add form data to request stream
                    System.IO.Stream requestStream = request.GetRequestStream();
                    requestStream.Write(buffer, 0, buffer.Length);
                    requestStream.Flush();
                    requestStream.Close();
                }
                else
                {
                    request = WebRequest.Create(uri + query);
                    request.Method = "GET";
                }
                // response
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                System.IO.Stream responseStream = response.GetResponseStream();
                StreamReader responseReader = new StreamReader(responseStream);
                // output
                output = responseReader.ReadToEnd();
                // clean-up
                responseReader.Close();
                responseStream.Close();
                response.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
 
            return output;
        }

Open in new window

0
Comment
Question by:Apyreal
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 25

Expert Comment

by:SStory
ID: 21821725
I'm not sure, but wouldn't you need to encode that like &lt; for <
like in html, to keep the page from thinking "<" is the beginning of a tag..that it subsequently won't find?
0
 
LVL 1

Accepted Solution

by:
Apyreal earned 0 total points
ID: 21821787
nope, actually. the it is already encoded. I found the problem about 5 minutes ago. IIS was treating %0A%3C as a possible dangerous request, so it would always fail it.

Fix was to place ValidateRequest="false" in the page to where i am posting. Not a perfect fix but it is the only one that works
0

Featured Post

The Eight Noble Truths of Backup and Recovery

How can IT departments tackle the challenges of a Big Data world? This white paper provides a roadmap to success and helps companies ensure that all their data is safe and secure, no matter if it resides on-premise with physical or virtual machines or in the cloud.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This document covers how to connect to SQL Server and browse its contents.  It is meant for those new to Visual Studio and/or working with Microsoft SQL Server.  It is not a guide to building SQL Server database connections in your code.  This is mo…
Lync server 2013 or Skype for business Backup Service Error ID 4049 – After File Share Migration
Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized …
Visualize your data even better in Access queries. Given a date and a value, this lesson shows how to compare that value with the previous value, calculate the difference, and display a circle if the value is the same, an up triangle if it increased…
Suggested Courses

764 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question