[Klone-users] Klone using server push

[Stefano Barbato]

Hi Andre,

the method to use really depends on what you need to accomplish.

If you need to share per-client data you can use sessions (url [1]).

If you want to share data between server processes you can use any  
facility the operating system offer (which one do you use btw?) like  
shared memory objects ([2]), memory mapped file [3], external file- 
based database like sqlite [4], etc.

If you want more then bare data sharing you can use an external daemon  
that centralizes klone daemons calls and that accept requests on tcp/ 
ip or unix sockets. Even a shell script called by inetd may be enough  
for example. It really depends on your requiremets.

The "iterative" model you tried allow just one connection at a time so  
may not be suitable for your particular need. If you need multiple  
concurrent access to the same KLone application you need to use the  
"fork" or "prefork" model type.

So there are many options but I need more info to point you to the  
right direction :)

bye,
s


[1] sessions: http://www.koanlogic.com/klone/api/html/group__session.html
[2] man shm_open
[3] mmap
[4] www.sqlite.org


On 16/lug/08, at 23:10, Andre Puschmann wrote:

> Hi Stefano,
>
> thanks for your quick reply.
> It worked as you described, thank you very much. However, I now got
> another problem/question.
>
> I've read that klone runs multiple processes to serve client  
> connections
> (prefork pattern).
>
> Is it possible to have shared resources for all processes?
>
> Lets say I want to have just _one_ socket descriptor (singleton) that
> I want to use.
> I tried to use the iterative model to do so. But if that single
> descriptor does a blocking read, the server hangs. So this is no
> solution. Would you recommend using pthread for this?
>
> I am not sure if I get something wrong :-)
>
> Regards,
> Andre
>
>
>
>
>
>
> Stefano Barbato wrote:
>> 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
>>>
>>> _______________________________________________
>>> Klone-users mailing list
>>> Klone-users at koanlogic.com
>>> http://koanlogic.com/cgi-bin/mailman/listinfo/klone-users
>>>
>>
>>
>> _______________________________________________
>> Klone-users mailing list
>> Klone-users at koanlogic.com
>> http://koanlogic.com/cgi-bin/mailman/listinfo/klone-users
>>
>>
>
>
> _______________________________________________
> Klone-users mailing list
> Klone-users at koanlogic.com
> http://koanlogic.com/cgi-bin/mailman/listinfo/klone-users
>