Need advices, displaying files in directory with CGI..

doctor_moron has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, i have CGI script and i need your advices about my code, and here's the scenario (Sorry for my english) :

The only query string allowed is param('page'), i mean user can reach my site with something like :

http://www.mysite.com/sorting.pl?page=2
[download]

that's mean user want to see files in page 2. And if user write http://www.mysite.com/sorting.pl #(without param('page')) that's mean param('page') = 0

The directory's path is :/home/lenn287/public_html/diary and there are 21 files in that directory. So there are 5 pages for 21 articles (5 files per page).

all 21 files are saved with html format and html extension, example :

200607140809.html (yyyy-mm-dd-hh-mm),
[download]

why ? the reason is i can easily just use reverse and sort function when i need to display the latest file at the top of my page.

About my files, they all have same characteristic, i'll take 1 example to make it clearer (with what i mean with "same characteristic"), here's the contents of 200607140809.html

<!--topic:Metallic Coating-->
<!--title:Galvanizing for Corrosion Protection - A Specifier's Guide t
+o Reinforcing 
Steel-->
<!--lang:English-->
<p>
Galvanizing for Corrosion Protection - A Specifier's Guide to Reinforc
+ing Steel
</p>
<p>
Corrosion and repair of corrosion damage aremulti-billion dollar probl
+ems. Observations on numerous structures show that corrosion of reinf
+orcing steel is either a prime factor, or at least an important facto
+r, contributing to the staining, cracking and spalling of concrete st
+ructures. These effects of corrosion often require costly
repairs and continued maintenance during the life of the structure. 
</p>
[download]

Have a look at the comment tags, they're exist in all my files, comment tags help me when i need to show only topic, title and lang in my page (open the file and use regex to find topic,title and lang) and one thing, there is no <html>,<body></body></html> tags in every files.

But im rather in a doubt about my code , it's like.. well, i dont know what to say (after learning few chapters from Perl Intermediate, i think i cant make things simpler....:">) that's why i need advices from you all

here's my code

#!/usr/bin/perl -wT


use strict;
use CGI qw/:standard/;
$CGI::DISABLE_UPLOADS =1;

my $page=param('page') || 0;
unless ($page =~ m/^(\d+)$/) { die }
$page = $1;


opendir(DIRE, "/home/lenn287/public_html/diary")|| er_msg("cant open d
+irectory: $!"); #UPDATED
[download]

my @files_exist = reverse sort map { $_ =~ s/^(\d+)\.html$/$1/; $_} grep { /^\w+.\.html$/} readdir DIRE;
[download]

my @files_exist = reverse sort  map { $_ =~ s/^(\d+)\.html$/$1/; $_} 
     grep { /^\d+.\.html$/} readdir DIRE;


closedir DIRE;

my $how_many_page = sub { 
                      my ($how) = @_;
                      $how = $how/5;
                      $how =~ /(\d+?).?(\d+)?/;
                      if(!$2) { return $1 } else { return $1+1 }
                     };    

my $file = sub {
  my $file_name = shift;
  my($topic,$title,$lang);
  open my $FH,'<', '/home/lenn287/public_html/diary/'.$file_name.".htm
+l";
  while(<$FH>) {
    $topic = $1 if /<!--topic:(.+?)-->/;
    $title = $1 if /<!--title:(.+?)-->/;
    $lang = $1 if /<!--lang:(.+?)-->/;
  }
  close $FH;
  return ($topic,br(),$title,br(),$lang,p());
};
if($page !~ /^[0-$how_many_page->($#files_exist)]$/) {
  print header,start_html,"invalid $page",end_html;
  exit(0);
} 

my ($next,$previous);
if($page < $how_many_page->($#files_exist)) {
  my $next_page=$page+1;
  $next = a({href=>"/cgi-bin/author.pl?page=$next_page"},"next"); 
} else {
  $next='';
}

if($page > 0) {
  my $previous_page=$page-1;
  $previous = a({href=>"/cgi-bin/author.pl?page=$previous_page"},"prev
+ious"); 
} else {
  $previous='';
}

my $first_file = $page*5;
my $last_file = $page*5+4;
my @FILES;
[download]

for($first_file; $first_file<=$last_file;$first_file++) { push @FILES, $file->($files_exist[$first_file]); }
[download]

for my $f($first_file..$last_file) {
  push @FILES, $file->($files_exist[$f]);
} 


print header,start_html;
print table({width=>720},
       Tr(
         td({width=>720,colspan=>2},
          img({src=>"/images/logo.gif",alt=>"logo",
               height=>90,width=>710}))),
       Tr(
         td({width=>600},@FILES),
         td({width=>120,rowspan=>100},
          img({src=>"/images/banner.gif",
               height=>450,width=>120,alt=>"banner"}))
         ),
       Tr(
         td($next,$previous)
        ));
        undef $file;
      
print end_html;
#UPDATED, error message
sub er_msg {
  my $error ="@_";
  print header,start_html,p($error),end_html;
  die "$error";
}
[download]

Thank you, zak

Comment on Need advices, displaying files in directory with CGI.. Select or Download Code

Replies are listed 'Best First'.
Re: Need advices, displaying files in directory with CGI.. by Leviathan (Scribe) on Jul 22, 2006 at 13:05 UTC
Some comments: `opendir(DIRE, "/home/lenn287/public_html/diary"); my @files_exist = reverse sort map { $_ =~ s/^(\d+)\.html$/$1/; $_} grep { /^\w+.\.html$/} readdir DIRE; closedir DIRE;` [download] Here your first regexp checks for (\w) and the second matches digits, so if you have a file called "bleh.html" it will pass the first grep but it will produce an empty entry on the display. Change the \w+ into \d+. `open my $FH,'<', '/home/lenn287/public_html/diary/'.$file_name.".html" +;` [download] You don't check if your open succeeded or not. `for($first_file; $first_file<=$last_file;$first_file++) {` [download] Since you're coding Perl: `for my $f ($first_file .. $last_file) {` [download] On another note, since you want to search within the files, you should either create an index of some sorts, instead of opening each file and searching, or use a database to store the contents and then you can use fulltext search on them. just a couple of cents -- Leviathan.	[reply] [d/l] [select]
Re: Need advices, displaying files in directory with CGI.. by Ieronim (Friar) on Jul 22, 2006 at 11:51 UTC
If i have understood you correctly, your code works, but it looks too ugly for you? If so, i recommend you to study HTML::Template. This module allowas you to leave all HTML in a separate template file and fill it with your data. The time you will spend learning HTML::Template will save you hours in future :) And it's a pain in the butt to create complex HTML pages with functions of CGI module :) `s;;Just-me-not-h-Ni-m-P-Ni-lm-I-ar-O-Ni;;tr?IerONim-?HAcker ?d;print`	[reply] [d/l]
Re: Need advices, displaying files in directory with CGI.. by fmerges (Chaplain) on Jul 22, 2006 at 10:57 UTC
Hi, Don't know in which context this run, or which constraint you have, but have you thought about using a template module for the HTML output, a module for paginating, and putting the data on a Database? Regards, fmerges at irc.freenode.net	[reply]
Re: Need advices, displaying files in directory with CGI.. by pope (Friar) on Sep 13, 2006 at 09:25 UTC
this should be slightly faster: `my @files_exist = reverse sort grep { defined } map { my $f = $_; $f =~ s/^(\d+)\.html$/$1/ ? $f : undef } readdir DIRE;` [download]	[reply] [d/l]