Re: get the size of a dynamically changing file fast ?
Gabriel Genellina wrote: En Wed, 23 Jan 2008 16:16:58 -0200, Stef Mientki [EMAIL PROTECTED] escribió: Yes, that's a small disadavantage of using a high-level language, where there's no flush available, and you assume it'll done automatically ;-) Uhm, there is a flush method for Python's files. From http:// I was talking about a high-level language, in which the sending program was written, (Delphi, not about Python ;-) In Delphi, flush(filevar) does work. flush is only valid for textfiles, not for binary files (at least in D7) anyway thanks, cheers, Stef -- http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
On Jan 22, 3:22 pm, Stef Mientki [EMAIL PROTECTED] wrote:
Mike Driscoll wrote:
On Jan 22, 3:35 pm, Stef Mientki [EMAIL PROTECTED] wrote:
Mike Driscoll wrote:
On Jan 17, 3:56 pm, Stef Mientki [EMAIL PROTECTED] wrote:
hello,
I've a program (not written in Python) that generates a few thousands
bytes per second,
these files are dumped in 2 buffers (files), at in interval time of 50
msec,
the files can be read by another program, to do further processing.
A program written in VB or delphi can handle the data in the 2 buffers
perfectly.
Sometimes Python is also able to process the data correctly,
but often it can't :-(
I keep one of the files open en test the size of the open datafile each
50 msec.
I have tried
os.stat ( ) [ ST_SIZE]
os.path.getsize ( ... )
but they both have the same behaviour, sometimes it works, and the data
is collected each 50 .. 100 msec,
sometimes 1 .. 1.5 seconds is needed to detect a change in filesize.
I'm using python 2.4 on winXP.
Is there a solution for this problem ?
thanks,
Stef Mientki
Tim Golden has a method to watch for changes in a directory on his
website:
http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_fo...
This old post also mentions something similar:
http://mail.python.org/pipermail/python-list/2007-October/463065.html
And here's a cookbook recipe that claims to do it as well using
decorators:
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/426620
Hopefully that will get you going.
Mike
thanks Mike,
sorry for the late reaction.
I've it working perfect now.
After all, os.stat works perfectly well,
the problem was in the program that generated the file with increasing
size,
by truncating it after each block write, it apperently garantees that
the file is flushed to disk and all problems are solved.
cheers,
Stef Mientki
I almost asked if you were making sure you had flushed the data to the
file...oh well.
Yes, that's a small disadavantage of using a high-level language,
where there's no flush available, and you assume it'll done
automatically ;-)
cheers,
Stef
Uhm, there is a flush method for Python's files. From http://
docs.python.org/lib/bltin-file-objects.html:
flush()
Flush the internal buffer, like stdio's fflush(). This may
be a no-op on some file-like objects.
As for an example:
import os
f = open('vikings.txt', 'wb')
os.stat('vikings.txt').st_size
0L
f.write('Spam, spam, spam, spam! ' * 1000) # Bloody vikings...
os.stat('vikings.txt').st_size
24576L
f.flush()
os.stat('vikings.txt').st_size
25000L
Is there something that I'm missing here?
--Jason
--
http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
thanks Mike,
sorry for the late reaction.
I've it working perfect now.
After all, os.stat works perfectly well,
the problem was in the program that generated the file with increasing
size,
by truncating it after each block write, it apperently garantees that
the file is flushed to disk and all problems are solved.
cheers,
Stef Mientki
I almost asked if you were making sure you had flushed the data to the
file...oh well.
Yes, that's a small disadavantage of using a high-level language,
where there's no flush available, and you assume it'll done
automatically ;-)
cheers,
Stef
Uhm, there is a flush method for Python's files. From http://
docs.python.org/lib/bltin-file-objects.html:
flush()
Flush the internal buffer, like stdio's fflush(). This may
be a no-op on some file-like objects.
As for an example:
import os
f = open('vikings.txt', 'wb')
os.stat('vikings.txt').st_size
0L
f.write('Spam, spam, spam, spam! ' * 1000) # Bloody vikings...
os.stat('vikings.txt').st_size
24576L
f.flush()
os.stat('vikings.txt').st_size
25000L
Is there something that I'm missing here?
hi Jason,
I was talking about a high-level language, in which the sending
program was written,
(Delphi, not about Python ;-)
cheers,
Stef
--
http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
En Wed, 23 Jan 2008 16:16:58 -0200, Stef Mientki [EMAIL PROTECTED] escribió: Yes, that's a small disadavantage of using a high-level language, where there's no flush available, and you assume it'll done automatically ;-) Uhm, there is a flush method for Python's files. From http:// I was talking about a high-level language, in which the sending program was written, (Delphi, not about Python ;-) In Delphi, flush(filevar) does work. Or are you using a TFileStream or similar? -- Gabriel Genellina -- http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
Mike Driscoll wrote: On Jan 17, 3:56 pm, Stef Mientki [EMAIL PROTECTED] wrote: hello, I've a program (not written in Python) that generates a few thousands bytes per second, these files are dumped in 2 buffers (files), at in interval time of 50 msec, the files can be read by another program, to do further processing. A program written in VB or delphi can handle the data in the 2 buffers perfectly. Sometimes Python is also able to process the data correctly, but often it can't :-( I keep one of the files open en test the size of the open datafile each 50 msec. I have tried os.stat ( ) [ ST_SIZE] os.path.getsize ( ... ) but they both have the same behaviour, sometimes it works, and the data is collected each 50 .. 100 msec, sometimes 1 .. 1.5 seconds is needed to detect a change in filesize. I'm using python 2.4 on winXP. Is there a solution for this problem ? thanks, Stef Mientki Tim Golden has a method to watch for changes in a directory on his website: http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_for_changes.html This old post also mentions something similar: http://mail.python.org/pipermail/python-list/2007-October/463065.html And here's a cookbook recipe that claims to do it as well using decorators: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/426620 Hopefully that will get you going. Mike thanks Mike, sorry for the late reaction. I've it working perfect now. After all, os.stat works perfectly well, the problem was in the program that generated the file with increasing size, by truncating it after each block write, it apperently garantees that the file is flushed to disk and all problems are solved. cheers, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
On Jan 22, 3:35 pm, Stef Mientki [EMAIL PROTECTED] wrote: Mike Driscoll wrote: On Jan 17, 3:56 pm, Stef Mientki [EMAIL PROTECTED] wrote: hello, I've a program (not written in Python) that generates a few thousands bytes per second, these files are dumped in 2 buffers (files), at in interval time of 50 msec, the files can be read by another program, to do further processing. A program written in VB or delphi can handle the data in the 2 buffers perfectly. Sometimes Python is also able to process the data correctly, but often it can't :-( I keep one of the files open en test the size of the open datafile each 50 msec. I have tried os.stat ( ) [ ST_SIZE] os.path.getsize ( ... ) but they both have the same behaviour, sometimes it works, and the data is collected each 50 .. 100 msec, sometimes 1 .. 1.5 seconds is needed to detect a change in filesize. I'm using python 2.4 on winXP. Is there a solution for this problem ? thanks, Stef Mientki Tim Golden has a method to watch for changes in a directory on his website: http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_fo... This old post also mentions something similar: http://mail.python.org/pipermail/python-list/2007-October/463065.html And here's a cookbook recipe that claims to do it as well using decorators: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/426620 Hopefully that will get you going. Mike thanks Mike, sorry for the late reaction. I've it working perfect now. After all, os.stat works perfectly well, the problem was in the program that generated the file with increasing size, by truncating it after each block write, it apperently garantees that the file is flushed to disk and all problems are solved. cheers, Stef Mientki I almost asked if you were making sure you had flushed the data to the file...oh well. Mike -- http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
Mike Driscoll wrote: On Jan 22, 3:35 pm, Stef Mientki [EMAIL PROTECTED] wrote: Mike Driscoll wrote: On Jan 17, 3:56 pm, Stef Mientki [EMAIL PROTECTED] wrote: hello, I've a program (not written in Python) that generates a few thousands bytes per second, these files are dumped in 2 buffers (files), at in interval time of 50 msec, the files can be read by another program, to do further processing. A program written in VB or delphi can handle the data in the 2 buffers perfectly. Sometimes Python is also able to process the data correctly, but often it can't :-( I keep one of the files open en test the size of the open datafile each 50 msec. I have tried os.stat ( ) [ ST_SIZE] os.path.getsize ( ... ) but they both have the same behaviour, sometimes it works, and the data is collected each 50 .. 100 msec, sometimes 1 .. 1.5 seconds is needed to detect a change in filesize. I'm using python 2.4 on winXP. Is there a solution for this problem ? thanks, Stef Mientki Tim Golden has a method to watch for changes in a directory on his website: http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_fo... This old post also mentions something similar: http://mail.python.org/pipermail/python-list/2007-October/463065.html And here's a cookbook recipe that claims to do it as well using decorators: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/426620 Hopefully that will get you going. Mike thanks Mike, sorry for the late reaction. I've it working perfect now. After all, os.stat works perfectly well, the problem was in the program that generated the file with increasing size, by truncating it after each block write, it apperently garantees that the file is flushed to disk and all problems are solved. cheers, Stef Mientki I almost asked if you were making sure you had flushed the data to the file...oh well. Yes, that's a small disadavantage of using a high-level language, where there's no flush available, and you assume it'll done automatically ;-) cheers, Stef -- http://mail.python.org/mailman/listinfo/python-list
Re: get the size of a dynamically changing file fast ?
On Jan 17, 3:56 pm, Stef Mientki [EMAIL PROTECTED] wrote: hello, I've a program (not written in Python) that generates a few thousands bytes per second, these files are dumped in 2 buffers (files), at in interval time of 50 msec, the files can be read by another program, to do further processing. A program written in VB or delphi can handle the data in the 2 buffers perfectly. Sometimes Python is also able to process the data correctly, but often it can't :-( I keep one of the files open en test the size of the open datafile each 50 msec. I have tried os.stat ( ) [ ST_SIZE] os.path.getsize ( ... ) but they both have the same behaviour, sometimes it works, and the data is collected each 50 .. 100 msec, sometimes 1 .. 1.5 seconds is needed to detect a change in filesize. I'm using python 2.4 on winXP. Is there a solution for this problem ? thanks, Stef Mientki Tim Golden has a method to watch for changes in a directory on his website: http://tgolden.sc.sabren.com/python/win32_how_do_i/watch_directory_for_changes.html This old post also mentions something similar: http://mail.python.org/pipermail/python-list/2007-October/463065.html And here's a cookbook recipe that claims to do it as well using decorators: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/426620 Hopefully that will get you going. Mike -- http://mail.python.org/mailman/listinfo/python-list
