Best method for inter process communications

[JamesHoward]

I am looking for a way of performing inter process communication over
XML between a python program and something else creating XML data.

What is the best way of performing this communication? I could bind a
socket to localhost and perform the data transfer that way, but that
seems inefficient due to the addition of TCP/IP or UDP/IP overhead.
Is there a way to stream data via a custom datastream (I.E. not STDIO,
STDERR, etc)?

Thanks in advance,
Jim Howard

[marduk]

On Mon, 2007-07-16 at 17:22 +0000, JamesHoward wrote:

I am looking for a way of performing inter process communication over
XML between a python program and something else creating XML data.

What is the best way of performing this communication? I could bind a
socket to localhost and perform the data transfer that way, but that
seems inefficient due to the addition of TCP/IP or UDP/IP overhead.
Is there a way to stream data via a custom datastream (I.E. not STDIO,
STDERR, etc)?

In *nix, you could also use a named pipe for cheap RPC (os.mkfifo()).

-a

[Steve Holden]

JamesHoward wrote:

I am looking for a way of performing inter process communication over
XML between a python program and something else creating XML data.

What is the best way of performing this communication? I could bind a
socket to localhost and perform the data transfer that way, but that
seems inefficient due to the addition of TCP/IP or UDP/IP overhead.
Is there a way to stream data via a custom datastream (I.E. not STDIO,
STDERR, etc)?

Nothing that portable across different platforms, I suspect.

However I see no reason why you can't use pipelines in Unix (in other
words what's wrong with using stdin/stdout?), and Windows offers
something called a named pipe. You could even use shared memory if you
wanted.

Given the radically inefficient representations that XML typically
requires, however, I think that worrying about localhost socket overhead
is unnecessary: if your application was *that* critical you wouldn't be
using XML in the first place.

regards
Steve
--
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Holden Web LLC/Ltd http://www.holdenweb.com
Skype: holdenweb http://del.icio.us/steve.holden
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[Grant Edwards]

On 2007-07-16, JamesHoward <Ja************@gmail.comwrote:

I am looking for a way of performing inter process communication over
XML between a python program and something else creating XML data.

What is the best way of performing this communication? I could bind a
socket to localhost and perform the data transfer that way, but that
seems inefficient due to the addition of TCP/IP or UDP/IP overhead.
Is there a way to stream data via a custom datastream (I.E. not STDIO,
STDERR, etc)?

You could use a named pipe or a Unix domain socket. The nice
thing about an IP socket is that you get network transparancy:
the two programs can be moved to two different machines.

--
Grant Edwards grante Yow! It's the RINSE CYCLE!!
at They've ALL IGNORED the
visi.com RINSE CYCLE!!

[JamesHoward]

Thanks for the updates. I think I will try named processes first, but
may just end up using local sockets in the end and not worry about the
overhead.

Jim Howard

[Hendrik van Rooyen]

"Steve Holden" <st***@holdenweb.comwrote:

Given the radically inefficient representations that XML typically
requires, however, I think that worrying about localhost socket overhead
is unnecessary: if your application was *that* critical you wouldn't be
using XML in the first place.

I heard a rumour once that a "hello world" string takes something like
10k bytes in XMLRPC - have never bothered to find out if its BS...

- Hendrik

[Marc 'BlackJack' Rintsch]

On Tue, 17 Jul 2007 08:08:45 +0200, Hendrik van Rooyen wrote:

I heard a rumour once that a "hello world" string takes something like
10k bytes in XMLRPC - have never bothered to find out if its BS...

Just try it out:

In [8]: import xmlrpclib

In [9]: a = xmlrpclib.dumps(('hello world',))

In [10]: len(a)
Out[10]: 80

In [11]: print a
<params>
<param>
<value><string>hello world</string></value>
</param>
</params>

Even with some additional boilerplate like XML declaration etc. there is
still a little bit room until 10Â*kB are reached. :-)

Ciao,
Marc 'BlackJack' Rintsch

[Irmen de Jong]

JamesHoward wrote:

I am looking for a way of performing inter process communication over
XML between a python program and something else creating XML data.

What is that "something else"?
--irmen

[Hendrik van Rooyen]

"Marc 'BlackJack' Rintsch" <bj_666@....netwrote:
On Tue, 17 Jul 2007 08:08:45 +0200, Hendrik van Rooyen wrote:

I heard a rumour once that a "hello world" string takes something like
10k bytes in XMLRPC - have never bothered to find out if its BS...

Just try it out:

In [8]: import xmlrpclib

In [9]: a = xmlrpclib.dumps(('hello world',))

In [10]: len(a)
Out[10]: 80

In [11]: print a
<params>
<param>
<value><string>hello world</string></value>
</param>
</params>

Even with some additional boilerplate like XML declaration etc. there is
still a little bit room until 10 kB are reached. :-)

LOL - so one could say it was a bit of an exaggeration...

Thanks - Hendrik