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Posted to modperl@perl.apache.org by martin langhoff <ma...@scim.net> on 2000/10/02 22:37:54 UTC
$r->header_only question (feeling a newbie!)
hi,
I've been developing with mod_perl for a while, but, thanks to
Richter's Embperl module and the excellent backwards compatibility
(regarding CGI.pm) I had never got anywhere near Apache::Request -- for
production, that is.
Now I have this very silly question, that I've boiled down to this
little snippet of code (which carries a remakable resemblance to the
example found in page 146 of the Eagle Book):
----------------------
#!/usr/bin/perl -w
use strict;
use Apache::Constants qw(:common);
my $r = Apache->request;
$r->content_type('text/html');
$r->send_http_header;
return OK unless $r->header_only; # THIS is the line I'm wondering about
$r->print(<<END);
<html><body><h1> Hello ! </h1>
<address> martin</address></body></html>
END
1;
------------------------
The issue is that I don't understand clearly what is this line supposed
to do. As it is, it'll make my script return an empty body ('document
contains no data!' said Navigator). Commented out, the proper contents
are sent. Reading the Eagle and `man Apache::Request` led me to thing
that the line is there to stop processing if all the client wants are
the headers (maybe because of a 'If-Modified-Since' parameter?).
Now shouldn't it be an 'if' instead of an 'unless'?
Am I too dumb today? Or is it just that it's monday?
martin
Re: $r->header_only question (feeling a newbie!)
Posted by Vivek Khera <kh...@kciLink.com>.
>>>>> "DT" == Drew Taylor <dr...@openair.com> writes:
DT> after changing "unless" to "if". Can anyone check what Apache defaults
DT> to if no status code is returned? I'm guessing it's "OK".
In perl, if you have no explicit return statement, the last value
computed (or returned from another sub call) will be returned. You
must explicitly issue a return if you want specific behavior.
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Vivek Khera, Ph.D. Khera Communications, Inc.
Internet: khera@kciLink.com Rockville, MD +1-301-545-6996
GPG & MIME spoken here http://www.khera.org/~vivek/
Re: $r->header_only question (feeling a newbie!)
Posted by Drew Taylor <dr...@openair.com>.
martin langhoff wrote:
>
> ... it made no difference ... :(
>
> Drew Taylor wrote:
> > I believe all you need to add is "return OK;" after your print
> > statement. Without that, Apache doesn't know what the status of the
> > request should be.
Doh. I missed what Tim caught. I believe Apache will assume an "OK" if
you don't explicitly return a status code. Thus your code _should_ work
after changing "unless" to "if". Can anyone check what Apache defaults
to if no status code is returned? I'm guessing it's "OK".
However, I'd still add a return OK after the print. :-)
--
Drew Taylor
Software Engineer
Phone: 617.351.0245
Fax 617.350.3496
OpenAir.com - Making Business a Breeze!
Open a free account today at www.openair.com
Re: $r->header_only question (feeling a newbie!)
Posted by martin langhoff <ma...@scim.net>.
... it made no difference ... :(
Drew Taylor wrote:
> I believe all you need to add is "return OK;" after your print
> statement. Without that, Apache doesn't know what the status of the
> request should be.
Re: $r->header_only question (feeling a newbie!)
Posted by Drew Taylor <dr...@openair.com>.
martin langhoff wrote:
>
> hi,
>
> I've been developing with mod_perl for a while, but, thanks to
> Richter's Embperl module and the excellent backwards compatibility
> (regarding CGI.pm) I had never got anywhere near Apache::Request -- for
> production, that is.
>
> Now I have this very silly question, that I've boiled down to this
> little snippet of code (which carries a remakable resemblance to the
> example found in page 146 of the Eagle Book):
> ----------------------
> #!/usr/bin/perl -w
> use strict;
> use Apache::Constants qw(:common);
>
> my $r = Apache->request;
> $r->content_type('text/html');
> $r->send_http_header;
>
> return OK unless $r->header_only; # THIS is the line I'm wondering about
>
> $r->print(<<END);
> <html><body><h1> Hello ! </h1>
> <address> martin</address></body></html>
> END
> 1;
>
> ------------------------
>
> The issue is that I don't understand clearly what is this line supposed
> to do. As it is, it'll make my script return an empty body ('document
> contains no data!' said Navigator). Commented out, the proper contents
> are sent. Reading the Eagle and `man Apache::Request` led me to thing
> that the line is there to stop processing if all the client wants are
> the headers (maybe because of a 'If-Modified-Since' parameter?).
I believe all you need to add is "return OK;" after your print
statement. Without that, Apache doesn't know what the status of the
request should be.
--
Drew Taylor
Software Engineer
Phone: 617.351.0245
Fax 617.350.3496
OpenAir.com - Making Business a Breeze!
Open a free account today at www.openair.com
Re: $r->header_only question (feeling a newbie!)
Posted by martin langhoff <ma...@scim.net>.
> martin,
> check out:
> http://www.ora.com/catalog/wrapmod/errata/wrapmod.699
Well, I guess fair is fair, the correction for page 146 (unless <=> if)
was there, I should've done my research better ...
anyway I do seem to be needing 'use Apache::Constants qw(:common);' to
run under strict and ^W=1 ...
martin
Re: $r->header_only question (feeling a newbie!)
Posted by ___cliff rayman___ <cl...@genwax.com>.
doug, lincoln,
looks like www.modperl.com needs a link to errata.
martin,
check out:
http://www.ora.com/catalog/wrapmod/errata/wrapmod.699
martin langhoff wrote:
> Thanks Tim and all,
> for-the-record, I did check www.modperl.com looking for an
> errata.
>
> marks down for O'Reilly technical reviewers :p
>
> martin
>
> Tim Tompkins wrote:
> >
> > This should be an "if" instead of "unless"
> >
> > return OK if $r->header_only;
> >
> > header_only() will return true if the request method is HEAD. You'll want
> > to simply return OK once you've gathered all the necessary outgoing headers
> > for HEAD requests.
--
___cliff rayman___cliff@genwax.com___http://www.genwax.com/
Re: $r->header_only question (feeling a newbie!)
Posted by martin langhoff <ma...@scim.net>.
Thanks Tim and all,
my gathering is that the sample script on page 146 of the Eagle:
- needed a 'use Apache::Constants(:common);' line
- needed a 'return OK;' line at EOF
- had an 'unless' that should've been an 'if'.
for-the-record, I did check www.modperl.com looking for an
errata.
Doug? Lincoln? I mean, it's one of the *simple* scripts, I do LOVE the
book, but I guess I'll have to trust this list a hunderd times more than
the book.
And, unless it was all my mistake, for some unbeknownst reason,
a few
marks down for O'Reilly technical reviewers :p
martin
Tim Tompkins wrote:
>
> This should be an "if" instead of "unless"
>
> return OK if $r->header_only;
>
> header_only() will return true if the request method is HEAD. You'll want
> to simply return OK once you've gathered all the necessary outgoing headers
> for HEAD requests.
Re: $r->header_only question (feeling a newbie!)
Posted by Tim Tompkins <ti...@arttoday.com>.
This should be an "if" instead of "unless"
return OK if $r->header_only;
header_only() will return true if the request method is HEAD. You'll want
to simply return OK once you've gathered all the necessary outgoing headers
for HEAD requests.
Thanks,
Tim Tompkins
----------------------------------------------
Programmer / Staff Engineer
http://www.arttoday.com/
----------------------------------------------
----- Original Message -----
From: "martin langhoff" <ma...@scim.net>
To: <mo...@apache.org>
Sent: Monday, October 02, 2000 1:37 PM
Subject: $r->header_only question (feeling a newbie!)
> hi,
>
> I've been developing with mod_perl for a while, but, thanks to
> Richter's Embperl module and the excellent backwards compatibility
> (regarding CGI.pm) I had never got anywhere near Apache::Request -- for
> production, that is.
>
> Now I have this very silly question, that I've boiled down to this
> little snippet of code (which carries a remakable resemblance to the
> example found in page 146 of the Eagle Book):
> ----------------------
> #!/usr/bin/perl -w
> use strict;
> use Apache::Constants qw(:common);
>
> my $r = Apache->request;
> $r->content_type('text/html');
> $r->send_http_header;
>
> return OK unless $r->header_only; # THIS is the line I'm wondering about
>
> $r->print(<<END);
> <html><body><h1> Hello ! </h1>
> <address> martin</address></body></html>
> END
> 1;
>
> ------------------------
>
> The issue is that I don't understand clearly what is this line supposed
> to do. As it is, it'll make my script return an empty body ('document
> contains no data!' said Navigator). Commented out, the proper contents
> are sent. Reading the Eagle and `man Apache::Request` led me to thing
> that the line is there to stop processing if all the client wants are
> the headers (maybe because of a 'If-Modified-Since' parameter?).
>
> Now shouldn't it be an 'if' instead of an 'unless'?
>
> Am I too dumb today? Or is it just that it's monday?
>
>
>
> martin
>
Re: $r->header_only question (feeling a newbie!)
Posted by Doug MacEachern <do...@covalent.net>.
On Mon, 2 Oct 2000, martin langhoff wrote:
> Now shouldn't it be an 'if' instead of an 'unless'?
yes, it should be an `if'. your script works fine for me with that
change.