CODEWITHSUNDEEP
asp.net
Laxmilal Menaria
Laxmilal Menaria

Reputation:

HttpWebRequestError: The server committed a protocol violation. Section=ResponseHeader Detail=CR must be followed by LF

I have created a sample asp.net application and try to scrape data from my server using httpwebrequest. But some times I got this above error. I have done some searches on google but all are saying that you should add the property "<httpWebRequest useUnsafeHeaderParsing="true" />" in web.config.

This property have 'UNSAFE" word, so I am too worried about this. I can't add this is in my site configuration. Is there any other option to read the response of my scrape URL. Please let me know how can it be possible without "<httpWebRequest useUnsafeHeaderParsing="true" />"

Thanks in advance, Laxmilal Menaria

Upvotes: 19

Views: 33660

Answers (4)

Todd Myhre
Todd Myhre

Reputation: 1310

You may want to check the content of your headers. Try adding the following, as suggested by this link:

Accept: text/html, application/xhtml+xml, */*

Upvotes: 0

marq
marq

Reputation: 828

Another possibility: when doing a POST, the server responds with a 100 continue in an incorrect way.

This solved the problem for me:

request.ServicePoint.Expect100Continue = false;

Upvotes: 2

Dinis Cruz
Dinis Cruz

Reputation: 4269

One way to debug this (and to make sure it is the protocol violation that is causing the problem), is to use Fiddler (Http Web Proxy) and see if the same error occurs. If it doesn't (i.e. Fiddler handled the issue for you) then you should be able to fix it using the UseUnsafeHeaderParsing flag.

If you are looking for a way to set this value programatically see the examples here: http://o2platform.wordpress.com/2010/10/20/dealing-with-the-server-committed-a-protocol-violation-sectionresponsestatusline/

Upvotes: 2

Justin Grant
Justin Grant

Reputation: 46683

This is certainly a server problem-- the server is not following the HTTP specification and the .NET client is flagging this as a potential problem. "Unsafe" is I think somewhat of a misnomer. There's not really a big security issue here, only non-compliance with the RFC which is bad but unfortunately not rare.

So, as you found in Google, the way to get around the problem is to apply the following configuration change:

<configuration> 
 <system.net> 
  <settings> 
   <httpWebRequest useUnsafeHeaderParsing="true" /> 
  </settings> 
 </system.net> 
</configuration>

Upvotes: 27

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