[Klone-users] Klone using server push

[Stefano Barbato]

Hi Andre,

KLone buffers the first 4096 bytes to give users the opportunity to  
modify header fields even after a few bytes have been written out with  
io_printf or io_write. You can for example use the response_redirect  
even after io_prints:

<%
	io_printf(out, "result 1");
	io_printf(out, "result 2");
	io_printf(out, "result 3");
	
	/* then if an error occurred you can still modify http header */
     	if(error_condition)
		response_redirect(response, "/error.kl1");
%>

The buffer is implemented as a filter attached to the response_t I/O  
object so you can avoid such buffer removing such filter and  
explicitly call the response_print_header() function (if you want an  
HTTP header at least). Here's the code:


<%
	...
	response_set_field(response, "Expires:","Mon, 26 Jul 1997 05:00:00  
GMT");

	io_codecs_remove(response_io(rs));
	response_print_header(response);

	io_printf(out, "---ThisRandomString---\n");
	...
%>

Take a look to the "Message Channel" KLone demo application that opens  
and keep opened a bidirectional channel between client and server:

http://koanlogic.com/download/klapp-msgchan-1.2.2.tar.gz

It's built on Flash XmlSocket component and a custom easy library we  
wrote (see msgchan.h).

bye!

s




On 08/lug/08, at 19:32, Andre Puschmann wrote:

> Hi all,
>
> I am trying to use a server push technique to avoid client side  
> polling
> for data.
> I am not sure if I am doing something wrong. For some reason Klone  
> sends
> all 4 "packets" in one single bunch. Well, at least wireshark  
> reports this!
> Seems like io_flush doesn't work?!
>
> Here is my sample code:
>
> <code>
> <%!
>   #include <stdio.h>
> %><%
>   int i;
>
>   response_set_content_type(response,
> "multipart/x-mixed-replace;boundary=---ThisRandomString---");
>   response_set_field(response, "Pragma:", "no-cache");
>   response_set_field(response, "Cache-Control", "no-cache, no-store,
> must-revalidate");
>   response_set_field(response, "Expires:", "Mon, 26 Jul 1997 05:00:00
> GMT");
>
>
>   io_printf(out, "---ThisRandomString---\n");
>
>   for (i = 1; i < 5; i++)
>   {
>      io_printf(out, "Content-type: text/html\n\n");
>      io_printf(out, "<h2>part %d</h2>\n", i);
>      io_printf(out, "---ThisRandomString---\n");
>      io_flush(out);
>      sleep(1);
>   }
> %>
> </code>
>
> Using the built-in cgi works for a shell script. Also here's the code
> for that one:
>
> <code>
> #!/bin/sh
> echo "HTTP/1.0 200"
> echo "Content-type:
> multipart/x-mixed-replace;boundary=---ThisRandomString---"
> echo ""
> echo "---ThisRandomString---"
> while true
> do
> echo "Content-type: text/html"
> echo ""
> echo "time: "
> date
> echo "---ThisRandomString---"
> sleep 5
> done
> </code>
>
>
> Comments are welcome!
>
> Best regards,
> Andre
>
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