[Zope] Re: Problem with keep-alive timeout

[Andrew Langmead]

On Jun 22, 2005, at 1:25 PM, Jonathan wrote:

> Set up your web page so that it has two frames: the main frame  
> (visable) invokes the long running zope script;  and a secondary  
> (hidden) frame uses a javascript routine (running on a timer) which  
> queries a no-op zope script. This should stop your browser from  
> timing out.
>
> Ugly, but it should work.

I don't think it would. Those two frames would or could be two  
separate requests. Starting the no-op script is going to have no  
effect on the entirely separate long running script.

When I said "would or could", it is because the exact behavior may  
depend on circumstances but the end result is the same. If Ralph is  
truly seeing HTTP 1.0 requests, then of course each connection would  
be independent and the completion of one request isn't going to reset  
the timeout for the other. In HTTP 1.1, you can combine multiple  
requests into a single socket connection, but I still don't think it  
would help. The way I've seen most browsers implement HTTP 1.1  
persistent connections, A connection opened for an initial user  
request (when the user clicks  a link or types a new address into the  
menu bar.) it send requests for the subordinate elements (the "src="  
attributes on the returned page) over the persistent connection. Once  
the initial request (including its subordinate components) is  
complete the connection is closed. Requests from different windows or  
different frames tend not to be intermingled within a socket  
connection. (and even then, do you want to depend on it? The spec  
says that the browser can send more than one request over a  
connection, not that it must.) Finally, The HTTP spec doesn't have  
facilities for out of order execution. You send a request, you get  
back the result. You send another request, you get back the next  
result. As soon as the long running request is sent, the "no-op"  
request will not be responded to.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.zope.org/pipermail/zope/attachments/20050622/40a8fab2/attachment.htm