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Posted to modperl@perl.apache.org by pradeep kumar <pr...@gmail.com> on 2005/09/01 14:52:52 UTC
$| doesn't work with mod_perl
Hi,
I have a perl script which uses $| to set autoflush on. Basically, it
flushes after every print. This script is working fine from the command line
when run using standalone perl interpreter. But when the same script is
accessed via mod_perl/apache setup, mod_perl is not flushing after every
print, instead buffering and printing all output at one shot.
Any idea why $| is not working with mod_perl.
Here is my sample script:
#!/usr/bin/perl -w
use CGI qw/:standard/;
use strict;
select(STDOUT);
$| = 1;
print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
<head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print STDOUT
'Testing'; print STDOUT "</body></html>";
Thanks in advance,
Pradeep
Re: $| doesn't work with mod_perl
Posted by Alexander Charbonnet <al...@charbonnet.com>.
Also, as long as you're using CGI.pm, you should use it to generate your HTML
output. Your script should probably look like this:
#!/usr/bin/perl -w
use strict;
use CGI qw/:standard/;
print
header(),
p('hello world'),
;
sleep 2;
print
p('testing'),
end_html(),
;
That'll generate XHTML Transitional compliant code, without having keep up
with it yourself (too much).
On Thursday 01 September 2005 07:56 am, Alexander Charbonnet wrote:
> Do you have mod_deflate active in your output chain? mod_deflate slurps up
> all its input and only prints when its buffer gets full.
>
> On Thursday 01 September 2005 07:52 am, pradeep kumar wrote:
> > Hi,
> >
> > I have a perl script which uses $| to set autoflush on. Basically, it
> > flushes after every print. This script is working fine from the command
> > line when run using standalone perl interpreter. But when the same script
> > is accessed via mod_perl/apache setup, mod_perl is not flushing after
> > every print, instead buffering and printing all output at one shot.
> > Any idea why $| is not working with mod_perl.
> >
> > Here is my sample script:
> >
> > #!/usr/bin/perl -w
> >
> > use CGI qw/:standard/;
> > use strict;
> > select(STDOUT);
> > $| = 1;
> > print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
> > <head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
> > sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print
> > STDOUT 'Testing'; print STDOUT "</body></html>";
> >
> >
> > Thanks in advance,
> > Pradeep
Re: $| doesn't work with mod_perl
Posted by Alexander Charbonnet <al...@charbonnet.com>.
Do you have mod_deflate active in your output chain? mod_deflate slurps up
all its input and only prints when its buffer gets full.
On Thursday 01 September 2005 07:52 am, pradeep kumar wrote:
> Hi,
>
> I have a perl script which uses $| to set autoflush on. Basically, it
> flushes after every print. This script is working fine from the command
> line when run using standalone perl interpreter. But when the same script
> is accessed via mod_perl/apache setup, mod_perl is not flushing after every
> print, instead buffering and printing all output at one shot.
> Any idea why $| is not working with mod_perl.
>
> Here is my sample script:
>
> #!/usr/bin/perl -w
>
> use CGI qw/:standard/;
> use strict;
> select(STDOUT);
> $| = 1;
> print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
> <head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
> sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print STDOUT
> 'Testing'; print STDOUT "</body></html>";
>
>
> Thanks in advance,
> Pradeep
Re: [mp2] $| doesn't work with mod_perl
Posted by "Philip M. Gollucci" <pg...@p6m7g8.com>.
Alexander Charbonnet wrote:
> Are you sure mod_deflate isn't one of your active Apache filters? mod_deflate
> will not output until its buffer is full, $| notwithstanding. I tore my hair
> out trying to work around it, and ended up writing my own compression filter.
> But if you don't need compression, try disabling mod_deflate.
You might try Apache2::DebugFilter to look at the bucket contents. Its pretty well documented.
Its in my CPAN dir, previously by Stas.
--
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Re: [mp2] $| doesn't work with mod_perl
Posted by Alexander Charbonnet <al...@charbonnet.com>.
Are you sure mod_deflate isn't one of your active Apache filters? mod_deflate
will not output until its buffer is full, $| notwithstanding. I tore my hair
out trying to work around it, and ended up writing my own compression filter.
But if you don't need compression, try disabling mod_deflate.
-Alex
On Friday 16 September 2005 05:36 am, pradeep kumar wrote:
> Can you please elaborate on why apache filters can be an issue with the
> autoflush problem that I noticed ?
>
> Also, I noticed that the autoflush work properly when I flush it to a
> regular file. Its only when I choose STDOUT that the flushing gets delayed.
> Is there some buffering that happens with STDOUT alone ? I am confused if
> this is a modperl problem or an Apache problem.
>
> On 9/12/05, pradeep kumar <pr...@gmail.com> wrote:
> > Hi Tom,
> > I am using mp2.
> > Thanks and Regards,
> > Pradeep
> >
> > On 9/12/05, Tom Schindl <to...@gmx.at> wrote:
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > >
> > > What version of mp are you using if you are running mp2 i think the
> > > apache-filter-system is the problem.
> > >
> > > Tom
> > >
> > > pradeep kumar wrote:
> > > > Hi,
> > > >
> > > > I have a perl script which uses $| to set autoflush on. Basically, it
> > > > flushes after every print. This script is working fine from the
> > >
> > > command
> > >
> > > > line when run using standalone perl interpreter. But when the same
> > > > script is accessed via mod_perl/apache setup, mod_perl is not
> > > > flushing after every print, instead buffering and printing all output
> > > > at one
> > >
> > > shot.
> > >
> > > > Any idea why $| is not working with mod_perl.
> > > >
> > > > Here is my sample script:
> > > >
> > > > #!/usr/bin/perl -w
> > > >
> > > > use CGI qw/:standard/;
> > > > use strict;
> > > > select(STDOUT);
> > > > $| = 1;
> > > > print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END;
> > > > <html> <head> </head> <body> END print STDOUT 'hello'; print STDOUT
> > > > '<br>'; sleep(2); print STDOUT 'World'; print STDOUT '<br>';
> > > > sleep(2); print STDOUT 'Testing'; print STDOUT "</body></html>";
> > > >
> > > >
> > > > Thanks in advance,
> > > > Pradeep
> > >
> > > -----BEGIN PGP SIGNATURE-----
> > > Version: GnuPG v1.4.0 (GNU/Linux)
> > > Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org
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Re: [mp2] $| doesn't work with mod_perl
Posted by Tom Schindl <to...@gmx.at>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi pradeep,
is $r->flush(); working, or not?
Tom
pradeep kumar wrote:
> mod_deflate is not loaded on my system and I can still see this problem.
>
> I instrumented some portion of the code to understand the flow and I
> have some questions. The modperl_filter.c has a function
> modperl_wbucket_flush(). Now the add_flush_bucket variable that is
> passed to this function is not set even when $| is enabled. If I
> manually set it, the autoflush happens as expected. I wanted to know
> when this variable is set and why setting it manually seems to solve the
> problem.
>
> Thanks in advance for any help on this.
>
>
> On 9/23/05, *Tom Schindl* <tomAtLinux@gmx.at <ma...@gmx.at>>
> wrote:
>
> Does $r->rflush(); help? Although it should do the same then seting $|
> to undef.
>
> Tom
>
> Tom Schindl wrote:
>> pradeep kumar wrote:
>
>>>>Can you please elaborate on why apache filters can be an issue
> with the
>>>>autoflush problem that I noticed ?
>>>>
>>>>Also, I noticed that the autoflush work properly when I flush it to a
>>>>regular file. Its only when I choose STDOUT that the flushing gets
>>>>delayed. Is there some buffering that happens with STDOUT alone ?
> I am
>>>>confused if this is a modperl problem or an Apache problem.
>>>>
>
>
>> Well I guess that I read it a while ago but I'm not sure of. As
> far as I
>> understand the Apache2-Filter-System because a bucket is only sent to
>> the filter system after the BUFFER is full. But I really have no idea
>> what happens behind the scences after the print-call.
>
>> Maybe Stas, Geoff or someone else can look at this and tell you more.
>
>> Tom
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Re: [mp2] $| doesn't work with mod_perl
Posted by pradeep kumar <pr...@gmail.com>.
mod_deflate is not loaded on my system and I can still see this problem.
I instrumented some portion of the code to understand the flow and I have
some questions. The modperl_filter.c has a function modperl_wbucket_flush().
Now the add_flush_bucket variable that is passed to this function is not set
even when $| is enabled. If I manually set it, the autoflush happens as
expected. I wanted to know when this variable is set and why setting it
manually seems to solve the problem.
Thanks in advance for any help on this.
On 9/23/05, Tom Schindl <to...@gmx.at> wrote:
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Does $r->rflush(); help? Although it should do the same then seting $|
> to undef.
>
> Tom
>
> Tom Schindl wrote:
> > pradeep kumar wrote:
> >
> >>>Can you please elaborate on why apache filters can be an issue with the
> >>>autoflush problem that I noticed ?
> >>>
> >>>Also, I noticed that the autoflush work properly when I flush it to a
> >>>regular file. Its only when I choose STDOUT that the flushing gets
> >>>delayed. Is there some buffering that happens with STDOUT alone ? I am
> >>>confused if this is a modperl problem or an Apache problem.
> >>>
> >
> >
> > Well I guess that I read it a while ago but I'm not sure of. As far as I
> > understand the Apache2-Filter-System because a bucket is only sent to
> > the filter system after the BUFFER is full. But I really have no idea
> > what happens behind the scences after the print-call.
> >
> > Maybe Stas, Geoff or someone else can look at this and tell you more.
> >
> > Tom
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> Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org
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>
Re: [mp2] $| doesn't work with mod_perl
Posted by Tom Schindl <to...@gmx.at>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Does $r->rflush(); help? Although it should do the same then seting $|
to undef.
Tom
Tom Schindl wrote:
> pradeep kumar wrote:
>
>>>Can you please elaborate on why apache filters can be an issue with the
>>>autoflush problem that I noticed ?
>>>
>>>Also, I noticed that the autoflush work properly when I flush it to a
>>>regular file. Its only when I choose STDOUT that the flushing gets
>>>delayed. Is there some buffering that happens with STDOUT alone ? I am
>>>confused if this is a modperl problem or an Apache problem.
>>>
>
>
> Well I guess that I read it a while ago but I'm not sure of. As far as I
> understand the Apache2-Filter-System because a bucket is only sent to
> the filter system after the BUFFER is full. But I really have no idea
> what happens behind the scences after the print-call.
>
> Maybe Stas, Geoff or someone else can look at this and tell you more.
>
> Tom
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Re: [mp2] $| doesn't work with mod_perl
Posted by Tom Schindl <to...@gmx.at>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
pradeep kumar wrote:
> Can you please elaborate on why apache filters can be an issue with the
> autoflush problem that I noticed ?
>
> Also, I noticed that the autoflush work properly when I flush it to a
> regular file. Its only when I choose STDOUT that the flushing gets
> delayed. Is there some buffering that happens with STDOUT alone ? I am
> confused if this is a modperl problem or an Apache problem.
>
Well I guess that I read it a while ago but I'm not sure of. As far as I
understand the Apache2-Filter-System because a bucket is only sent to
the filter system after the BUFFER is full. But I really have no idea
what happens behind the scences after the print-call.
Maybe Stas, Geoff or someone else can look at this and tell you more.
Tom
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Re: [mp2] $| doesn't work with mod_perl
Posted by pradeep kumar <pr...@gmail.com>.
Can you please elaborate on why apache filters can be an issue with the
autoflush problem that I noticed ?
Also, I noticed that the autoflush work properly when I flush it to a
regular file. Its only when I choose STDOUT that the flushing gets delayed.
Is there some buffering that happens with STDOUT alone ? I am confused if
this is a modperl problem or an Apache problem.
On 9/12/05, pradeep kumar <pr...@gmail.com> wrote:
>
> Hi Tom,
> I am using mp2.
> Thanks and Regards,
> Pradeep
>
> On 9/12/05, Tom Schindl <to...@gmx.at> wrote:
> >
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > What version of mp are you using if you are running mp2 i think the
> > apache-filter-system is the problem.
> >
> > Tom
> >
> > pradeep kumar wrote:
> > > Hi,
> > >
> > > I have a perl script which uses $| to set autoflush on. Basically, it
> > > flushes after every print. This script is working fine from the
> > command
> > > line when run using standalone perl interpreter. But when the same
> > > script is accessed via mod_perl/apache setup, mod_perl is not flushing
> > > after every print, instead buffering and printing all output at one
> > shot.
> > > Any idea why $| is not working with mod_perl.
> > >
> > > Here is my sample script:
> > >
> > > #!/usr/bin/perl -w
> > >
> > > use CGI qw/:standard/;
> > > use strict;
> > > select(STDOUT);
> > > $| = 1;
> > > print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
> > > <head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
> > > sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print
> > > STDOUT 'Testing'; print STDOUT "</body></html>";
> > >
> > >
> > > Thanks in advance,
> > > Pradeep
> >
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v1.4.0 (GNU/Linux)
> > Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org
> >
> > iD8DBQFDJTzSkVPeOFLgZFIRApj0AKCMTBdxV+2QHD3A09oXuZH86Qv1/wCgoSuu
> > 8w1b1u2xYzy6lZF9XJA3GD8=
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> >
>
>
Re:[mp2] $| doesn't work with mod_perl
Posted by pradeep kumar <pr...@gmail.com>.
Hi Tom,
I am using mp2.
Thanks and Regards,
Pradeep
On 9/12/05, Tom Schindl <to...@gmx.at> wrote:
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> What version of mp are you using if you are running mp2 i think the
> apache-filter-system is the problem.
>
> Tom
>
> pradeep kumar wrote:
> > Hi,
> >
> > I have a perl script which uses $| to set autoflush on. Basically, it
> > flushes after every print. This script is working fine from the command
> > line when run using standalone perl interpreter. But when the same
> > script is accessed via mod_perl/apache setup, mod_perl is not flushing
> > after every print, instead buffering and printing all output at one
> shot.
> > Any idea why $| is not working with mod_perl.
> >
> > Here is my sample script:
> >
> > #!/usr/bin/perl -w
> >
> > use CGI qw/:standard/;
> > use strict;
> > select(STDOUT);
> > $| = 1;
> > print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
> > <head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
> > sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print
> > STDOUT 'Testing'; print STDOUT "</body></html>";
> >
> >
> > Thanks in advance,
> > Pradeep
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.0 (GNU/Linux)
> Comment: Using GnuPG with Mandriva - http://enigmail.mozdev.org
>
> iD8DBQFDJTzSkVPeOFLgZFIRApj0AKCMTBdxV+2QHD3A09oXuZH86Qv1/wCgoSuu
> 8w1b1u2xYzy6lZF9XJA3GD8=
> =VjYy
> -----END PGP SIGNATURE-----
>
Re: $| doesn't work with mod_perl
Posted by Tom Schindl <to...@gmx.at>.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
What version of mp are you using if you are running mp2 i think the
apache-filter-system is the problem.
Tom
pradeep kumar wrote:
> Hi,
>
> I have a perl script which uses $| to set autoflush on. Basically, it
> flushes after every print. This script is working fine from the command
> line when run using standalone perl interpreter. But when the same
> script is accessed via mod_perl/apache setup, mod_perl is not flushing
> after every print, instead buffering and printing all output at one shot.
> Any idea why $| is not working with mod_perl.
>
> Here is my sample script:
>
> #!/usr/bin/perl -w
>
> use CGI qw/:standard/;
> use strict;
> select(STDOUT);
> $| = 1;
> print STDOUT "Content-type: text/html\n\n"; print STDOUT <<END; <html>
> <head> </head> <body> END print STDOUT 'hello'; print STDOUT '<br>';
> sleep(2); print STDOUT 'World'; print STDOUT '<br>'; sleep(2); print
> STDOUT 'Testing'; print STDOUT "</body></html>";
>
>
> Thanks in advance,
> Pradeep
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