Re: [jetty-users] ProxyServlet hang with 304 and Content-Length header

[Greg Wilkins <gregw@xxxxxxxxxxx>]

Mike,

I think that it is the downstream server that is primarily at fault.

I guess we could update the client to ignore content-length on 304, but my concern is that is only 1 way that a server could be bad.  What if it actually sent a body with that response?    I guess we need to close that connection after such and error.

Can you open a JIRA/bugzilla for this and we will consider.

cheers

On 3 March 2011 00:48, Mike Pilone <MPilone@xxxxxxx> wrote:

I'm trying to use the ProxyServlet to create a simple frontend SSL proxy and I'm seeing it hang on 304 responses from my backend. After about 30 seconds the proxy returns with a gateway timeout error for the request.

 

I did discover that the backend is setting a Content-Length header for the 304 response so I'm assuming the problem is that the ProxyServlet is waiting for the content, even though it will never be returned. I filed an issue against Spring (the backend servlet) for setting the Content-Length header, but I'm not convinced that it is all their fault. Based on my reading of RFC 2616, both ends seem to behave incorrectly.

 

RFC 2616 section 10.3.5 says,

 

"If the conditional GET used a strong cache validator (see section 13.3.3), the response SHOULD NOT include other entity-headers. Otherwise (i.e., the conditional GET used a weak validator), the response MUST NOT include other entity-headers; this prevents inconsistencies between cached entity-bodies and updated headers."

 

of course, RFC 2616 section 4.4 says,

 

"Any response message which "MUST NOT" include a message-body (such as the 1xx, 204, and 304 responses and any response to a HEAD request) is always terminated by the first empty line after the header fields, regardless of the entity-header fields present in the message."

 

So, in either case (strong or weak validators), it seems like the backend servlet should not be setting a Content-Length header because clients could hang waiting for the content. However, clients should be smart enough to ignore content-length header on a 304 by looking for the first empty line.

 

From my googling, it looks like this is a reappearance of Jetty issue 283: http://jira.codehaus.org/browse/JETTY-283. Looking at the code, the ProxyServlet appears to have been rewritten and the bug reintroduced.

 

Thoughts?

 

-mike

 

 

 

 | Mike Pilone | Software Architect, Distribution | mpilone@xxxxxxx | o: 202-513-2679  m: 703-969-7493

 

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