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Posted to modperl@perl.apache.org by Greg Cope <gj...@rubberplant.freeserve.co.uk> on 2000/06/08 21:24:03 UTC
Re: Template techniques [ newbie alert + long ]
Chris Winters wrote:
>
> * shane@isupportlive.com (shane@isupportlive.com) [000608 11:07]:
> > I'm curious Matt, as opposed to what?, reparsing the template each
> > run? Clearly reparsing would be a big loser in terms of performance.
> >
> > But what other technique could be used..., hrm.., without direct
> > control over the pipe, I really don't think it would get too much
> > better than this. I mean, you could yank out sections and stuff it
> > into an array that would be like: text, coderef, coderef, text, etc.
> > Like in an ASP template you would parse the file, grab sections
> > between <% %> and eval it as a code ref, and stuff it into your array.
> > But this would probably not work specifically in ASP's case, but you
> > might be able to pull it off in Embperl. (Unless the array itself
> > could also point to arrays, etc.) Overall..., I think compiling it
> > directly makes a lot more sense in 99.999% of template languages...,
> > otherwise you'd end up putting too many restrictions on the template
> > language itself.
> >
> > Hmm..., sort of an interesting question, what ways could be utilized
> > in order to maximize speed in template execution. I thought about
> > this a while ago, but after the fact I have to agree with Matt...,
> > just evaling each template as a package, or a code ref would be a
> > lot quicker, and if you could cook up another scheme, the resulting
> > code complexity might not pan out to be worth it.
>
> The newest version of Template Toolkit (currently in alpha) supports
> compiling templates to perl code. See about 2/3 of the way down the
> the README at www.template-toolkit.org. Why reinvent the wheel? :)
My original question was not related to templates (I'll use embperl for
that) - the area I was trying to explore was how to read a template (all
HTML with a few <!--TAGS--> in it) and the sub in the new content.
My pages usually have serveral templates - or one larger template with
comments arround iterative bits (tables) so that I end up with a main
template which may look something like:
<html>
<head>
<title>
<!--TITLE-->
</title>
</head>
<body <!-- BODY -->>
<table>
<!--TABLE-->
</table>
</body></html>
and a table template:
<tr><td valign='foo' color='bar'><!--CELL--></td></tr>
The Designers / HTML coders I work with can then chop and change these
templates - I have made a template loader that strips the iterative
table content out into a seperate template, so that they can code a fake
entry for design reasons - and I then strip it out (looking for some
special HTML comment tags).
In a startup.pl The code then looks somat like this forgive the probably
uncompliable perl etc ... this is for explaination purposes:
use vars (MAINTMP TABLETMP);
$MAINTMP = &load('main.tmp');
$TABLETMP = &load('table.tmp');
sub load {
my $file = shift;
my $html = '';
open (TEMPLATE, $file) || die ('Cant open : ', $file, $!);
while (<TEMPLATE>) {
chomp;
$_ =~ s/^\s+//;
$_ =~ s/\s+$//;
$html = $html . $_;
}
close (TEMPLATE) || die ('Cant close : ', $file, $!);
return $html;
}
then in a handler:
sub makeTableContents {
# assumes @_ is a nice list in order of values
# to insert into the table ..
my $template = $TABLETMP;
my $tablehtml;
foreach (@_) {
$template ~= s/<!--CELL-->/$_/;
$tableHTML .= $template;
}
return $tableHTML;
}
sub doStuff {
# assumes that it is passed in the return value from
# makeTableContents and a title
my $tableHTML = shift;
my $title = shift;
my $template = $MAINTMP;
$template =~ s/<!--TITLE-->/$title/;
$template =~ s/<!--TABLE-->/$tableHTML/;
return $template;
}
Then when I want to send it I just print the return value of doStuff
This may not be OO - but it is simplistic, and although not benchmarked,
should be fast. I have seen another OO ish implentation, that uses a
hash a bit like Mats example - this allows more flexibility as all you
need do is add the tag to the HTML, and then add the tag to the hash -
then when you do the regex it gets put in.
Has anyone any suggestions as to speeding this up - yet keeping it
simple - I have played with referances to avoid all the variable copying
etc . ?
Thinking about it Mat's example is far more scalable, and reusable.
I am enjoying this thread ;-)
Greg Cope
> Chris
>
> --
> Chris Winters
> Internet Developer INTES Networking
> cwinters@intes.net http://www.intes.net/
> Integrated hardware/software solutions to make the Internet work for you.
Re: Template techniques [ newbie alert + long ]
Posted by "Randal L. Schwartz" <me...@stonehenge.com>.
>>>>> "Perrin" == Perrin Harkins <pe...@primenet.com> writes:
Perrin> I think the world's record for most compact implementation
Perrin> goes to Randal for a small post you can find in the archive here:
Perrin> http://forum.swarthmore.edu/epigone/modperl/beldkhinfol/8ciuhsney0.fsf@gadget.cscaper.com
Ahh yes, Apache::Cachet (it's a cache, eh?), mostly proof of concept,
aborted when I started using HTML::Mason in a serious way.
--
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<me...@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
Perl/Unix/security consulting, Technical writing, Comedy, etc. etc.
See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training!
Re: Template techniques [ newbie alert + long ]
Posted by Ged Haywood <ge...@jubileegroup.co.uk>.
Hi there,
On Thu, 8 Jun 2000, Perrin Harkins wrote:
> use references for passing data.
But see "Advanced Perl Programming" pages 9 (Performance Efficiency)
and 44 (Using Typeglob Aliases).
73,
Ged.
Re: Template techniques [ newbie alert + long ]
Posted by Perrin Harkins <pe...@primenet.com>.
On Thu, 8 Jun 2000, Greg Cope wrote:
> > > - the area I was trying to explore was how to read a template (all
> > > HTML with a few <!--TAGS--> in it) and the sub in the new content.
> >
> > Embperl would work fine for that, but it's overkill. Your substitution
> > approach is slower than compiling to perl subs, especially since you have
> > to load the file, but saves lots of memory and is fine for something as
> > simple as this.
>
> Can you enlighten me into the compiling to perl subs ?
It's what Matt was talking about. Your program parses the template,
generates perl code that produces the correct output, evals the code, and
stores the results in a sub reference which you can call whenever you want
that template.
The first time I ever saw this done was with ePerl, but I don't know if
that was really the first. All the embedded perl systems popular around
here (Embperl, Apache::ASP, Mason, etc.) use some variation on this
technique. I think the world's record for most compact implementation
goes to Randal for a small post you can find in the archive here:
http://forum.swarthmore.edu/epigone/modperl/beldkhinfol/8ciuhsney0.fsf@gadget.cscaper.com
> The file gets loaded once into shared memory - most (stripped) HTML
> files are only a few 10's of K.
>
> Also the file gets loaded once at startup - not during the request
> stage.
You probably won't get much faster than that then, no matter what you do.
Just make sure your regexps are fast (maybe use "study"?) and use
references for passing data.
- Perrin
Re: Template techniques [ newbie alert + long ]
Posted by Greg Cope <gj...@rubberplant.freeserve.co.uk>.
Perrin Harkins wrote:
>
> On Thu, 8 Jun 2000, Greg Cope wrote:
> > My original question was not related to templates (I'll use embperl for
> > that)
>
> Well, I'm confused now. You'll use Embperl for templates but you're not
> using Embperl for templates?
I use Embperl when I want a templating system - but not when using HTML
templates (wrong use of names on my part) - I am refering to a template
in this case as an HTML file with a few special tags.
>
> > - the area I was trying to explore was how to read a template (all
> > HTML with a few <!--TAGS--> in it) and the sub in the new content.
>
> Embperl would work fine for that, but it's overkill. Your substitution
> approach is slower than compiling to perl subs, especially since you have
> to load the file, but saves lots of memory and is fine for something as
> simple as this.
Can you enlighten me into the compiling to perl subs ?
The file gets loaded once into shared memory - most (stripped) HTML
files are only a few 10's of K.
Also the file gets loaded once at startup - not during the request
stage.
> > Has anyone any suggestions as to speeding this up - yet keeping it
> > simple - I have played with referances to avoid all the variable copying
> > etc . ?
>
> Caching templates in memory would certainly help, but you'll eat up a
> chunk of RAM.
If the html is usually reasonable in size, and the code I C&P'ed strips
the template into one long strip with spaces / tabs (designers making
things all indented etc ..) at each end of the string - and chomp.
Also the templates are modular - in that one template covers main part
of the page, and other templates cover the rest. This helps contiunity
in HTML design etc .. (i.e only make one changen in one place)
Thanks for the input.
Greg
>
> - Perrin
Re: Template techniques [ newbie alert + long ]
Posted by Perrin Harkins <pe...@primenet.com>.
On Thu, 8 Jun 2000, Greg Cope wrote:
> My original question was not related to templates (I'll use embperl for
> that)
Well, I'm confused now. You'll use Embperl for templates but you're not
using Embperl for templates?
> - the area I was trying to explore was how to read a template (all
> HTML with a few <!--TAGS--> in it) and the sub in the new content.
Embperl would work fine for that, but it's overkill. Your substitution
approach is slower than compiling to perl subs, especially since you have
to load the file, but saves lots of memory and is fine for something as
simple as this.
> Has anyone any suggestions as to speeding this up - yet keeping it
> simple - I have played with referances to avoid all the variable copying
> etc . ?
Caching templates in memory would certainly help, but you'll eat up a
chunk of RAM.
- Perrin