How can I display DBM entries in an HTML table?

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

Hi ... it's been a while since I have frequented the monastery ^^; but I have finally had time to work on a new project. I am creating a simple news database program that saves to a DBM style database, and can add entries into it, using hashes. I am also using HTML::Template for the first real time to seperate the code from the HTML. My question is, how can I have this code snippet display all of the database entries in a table? Thanks for any help!
note:I have not added the file lock yet, but that will be added before I actually use this code in a bigger project later. I am sure that there is a lot of the program that could be much more efficient than it is, if so, please let me know, so I can learn and fix it! Thanks again.

Here is the first file, the actual code file (news.pl):

#!/usr/bin/perl -w
use HTML::Template;
use CGI qw (:standard);
use CGI::Carp qw(fatalsToBrowser);
use DB_File;

@fields = ("title","date","author","news");
$q = new CGI;
print $q->header;

my $template = HTML::Template->new(filename => 'news.tmpl');

$filename="database.db";
tie(%hash, "DB_File", $filename) or die "Can't open $filename: $!";

#add();

my @loop_data = ();  # initialize an array to hold your loop
my @keys = ();
my @values = ();

get_values();
sub get_values {
while (($key,$value) = each %hash) {
  push(@keys, $key);
  push(@values, $value);
}
}

while (@keys and @values) {
  my %row_data;  # get a fresh hash for the row data
  
# fill in this row
  $row_data{KEY} = shift @keys;
  $row_data{VALUE} = shift @values;

  # the crucial step - push a reference to this row into the loop!
  push(@loop_data, \%row_data);
}

my @newfields = ();
foreach $field (@fields){
  push(@newfields, $field);
}
while (@newfields) {
  get_values();
  my %nf_row_data;
  $nf_row_data{FIELD} = shift @newfields;
  push(@field_data, \%nf_row_data);
}

#delete();
untie %hash;

$template->param(
    SHOW_ALL_LOOP => \@loop_data,
    FIELD_LOOP => \@field_data);

print $template->output;

sub add {
  $key = time();
  $record = $key;
  foreach $field(@fields){
    $record  .= "\|$field";
  }
  $hash{$key}  = "$record";
}

sub delete {
  %hash = ();
}
[download]

And here is the HTML Template file for the code (news.tmpl):

<html>
<head><title>news.tmpl</title></head>
<body bgcolor=#eeeeee>
<center>

<TMPL_LOOP NAME="SHOW_ALL_LOOP">
  <table width=400 border=1 cellspacing=0 cellpadding=0>
  <tr><td valign=top bgcolor=#dddddd>
  <b>Key</b>:<TMPL_VAR NAME="KEY"><br>
  <b>Value</b>:<TMPL_VAR NAME="VALUE"><br><br>
  </td></tr>
  </table><br>
</TMPL_LOOP>

<table border=1 cellspacing=0 cellpadding=0>
<tr>
<TMPL_LOOP NAME="FIELD_LOOP">
  <td><TMPL_VAR NAME="FIELD"></td>
</TMPL_LOOP>
</tr>
</table>

</center>
</body>
</html>
[download]

That should be all you need to check this program. By the way, this is not a homework question, this is a question that I would like to figure out how to do this sort of program correctly, because last summer I created a web framework news type of thing, but it sucked, and I am hoping this will be better overall than my last project. The old project's site page is at www.hashes.f2s.com ... but it is terrible ^_- so don't see it.

Andy Summers

Edit Petruchio Sat Dec 29 03:17:53 UTC 2001 - Added READMORE tag.

Comment on How can I display DBM entries in an HTML table? Select or Download Code

Replies are listed 'Best First'.
Re: How can I display DBM entries in an HTML table? by jepri (Parson) on Dec 29, 2001 at 08:47 UTC
Aaah! Evil! Where's your use strict?! If you had one there you'd see that @field_data is being created in one while loop and then passed to a function from a different context. Bad! Doing things like that makes it hard for us to read, which may explain your lack of responses. I like they way I can recognise the comments from the HTML::Template examples ;) I spent a lot of time copying out that example and modifying it too. Without claiming I know much better, I would probably shorten this bit a little: `my @newfields = (); foreach $field (@fields){ push(@newfields, $field); } while (@newfields) { get_values(); my %nf_row_data; $nf_row_data{FIELD} = shift @newfields; push(@field_data, \%nf_row_data); }` [download] can be written as (untested): `my @newfields = (); foreach $field (@fields){ get_values(); my %nf_row_data; $nf_row_data{FIELD} = $_; push(@field_data, \%nf_row_data); }` [download] But why do you have get_values() there at all? You don't need it, because you have already used @keys and @values, right? Also it is bad practise to have get_values() modify a global variable. Pass @keys and @values out of the subroutine like this: `return \@keys, \@values` Put use strict; at the top of your program, fix all the errors, then post again. ____________________ Jeremy I didn't believe in evil until I dated it.	[reply] [d/l] [select]
Re: How can I display DBM entries in an HTML table? by chromatic (Archbishop) on Dec 30, 2001 at 08:17 UTC
This snippet: `while (($key,$value) = each %hash) { push(@keys, $key); push(@values, $value); }` [download] can be replaced with the built-in keys and values functions. I second the recommendation to enable strict and to get rid of your global variables. It's also my opinion that you're really overthinking things -- does HTML::Template provide a means to iterate over hash keys? If so, I'd just do that, rather than converting from hash to array of hashrefs.	[reply] [d/l]

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