Category: Software Development

Today I spent the rest of the day to fix one problem with Reports. It gave a JavaScript error (I hate JavaScript!) when some filter was built. The problem appeared only in Quote reports. I realized that it may happend because I added two new fields in the file vardefs.php. This file contains descriptions of all fields belonged to specific class:
'tax_usdollar' =>
array (
'name' => 'tax_usdollar',
'vname' => 'LBL_TAX_USDOLLAR',
'type' => 'decimal',
'len' => '20,2',
),

I commented out them but it didn’t resolve the problem. I observed that the error appeared when I chose “money” fields: Tax, Total Amount, Subtotal etc. I checked out their types in the vardefs.php and found the bug. The type was ‘decimal’ but when Report form was built it couldn’t find any operation for this data type. I replaced all decimal types by float and after that Quote report started work fine.
We still use SugarCRM-Pro-3.0.1. It’s difficult to switch to the latest version because we did some customization and fixed many bugs. Regarding the bug with building the list of operations for data type ‘decimal’ – it was fixed in the version 4.0. Cool! The developer team spent six months to fix this simple bug.

Once I found the solution how to create Perl SOAP server with SSL. Here is a path for a module SOAP::Transport::HTTP::Daemon:

392c392,399
- sub new { require HTTP::Daemon;
---
+ sub SSL {
+ my $self = shift->new;
+ @_ ? ($self->{_SSL} = shift, return $self) : return
$self->{_SSL};
+ }
+
+ sub http_daemon_class { shift->SSL ? 'HTTP::Daemon::SSL' : 'HTTP::Daemon' }
+
+ sub new {
401c408,415
- $self->{_daemon} = HTTP::Daemon->new(@params) or Carp::croak "Can't create daemon: $!";
---
+
+ # use SSL if there is any parameter with SSL_* in the name
+ $self->SSL(1) if !$self->SSL && grep /^SSL_/, @params;
+ my $http_daemon = $self->http_daemon_class;
+ eval "require $http_daemon" or Carp::croak $@ unless UNIVERSAL::can($http_daemon => 'new');
+ $self->{_daemon} = $http_daemon->new(@params) or Carp::croak "Can't create daemon: $!";

Now, the server can be created like that:

my $daemon = SOAP::Transport::HTTP::Daemon->new(
LocalPort => 81,
Listen => 1,
SSL_use_cert => 1,
SSL_key_file => 'soap_server.key',
SSL_cert_file => 'soap_server.cert');

and client should use https instead of HTTP.
Unfortunatelly, I didn’t have a necessity to use it but may be in the future it’ll help me.

Algorithm::CheckDigits is a Perl extension which provides a functionality to generate and test check digits. It implements many algorithms to work with ISBN, UPS, VAT number etc. The workflow is very simple. First, the appropriate algorithm should be choosen:

use Algorithm::CheckDigits;
$isbn = CheckDigits('ISBN');

Then it’s possible to check existing number:

$isbn->is_valid('3-930673-48-7');

Get from existing number the check digit or base number:

$cd = $isbn->checkdigit('3-930673-48-7'); # $CD = '7'
$bn = $isbn->basenumber('3-930673-48-7'); # $bn = '3-930673-48'

or generate the check digit for the base number:

$cn = $isbn->complete('3-930673-48'); # $cn = '3-930673-48-7'

The list of available algorithms can be retrieving by method method_list():
Algorithm::CheckDigits->method_list();
It isn’t exported. So, the module name should be used when this method is called.
Algorithm::CheckDigits is very useful module and it save a lot of your time if you need to implement of calculation of check digit.

Continue reading Perl Modules: Algorithm::CheckDigits

Recently I tried to use Class::DBI – one of the best Perl frameworks to create a persistent objects – with Postgresql and I faced with big problem. After the second or third request to the database it gave me an error:

Can't use an undefined value as an ARRAY reference at Class/DBI.pm line 1125

It was very strange for me because I used Class::DBI with Mysql in the three projects and I didn’t have any problems with Class::DBI. I made a search of this error and I was very surprised because I found just a couple of pages in Google. It seems that Class::DBI and Postgresql are used together rarely.
However, the suggestions of Perrin Harkins helped me to solve my problem. As I understand Class::DBI cannot work properly together with Apache::DBI in case transaction database.
To use Class::DBI into your classes you have to create a base class which inherits Class::DBI, inherited by all your classes and defined connection to the database:

__PACKAGE__->set_db('Main',
'dbi:' . $config->{'database'}->{'dbtype'} . ':database=' . $config->{'database'}->{'database'},
$config->{'database'}->{'username'},
$config->{'database'}->{'password'}, $attrs
);

Continue reading Class::DBI, Postgrsql and mod_perl

Let’s suppose you need to have only one copy of your Perl script running. An elegant and short way to do that is a lock the script by itself. Add this code at the begginig of your script and it’ll avoid to run more than one copy.

use Fcntl ':flock';
open SELF, "< $0" or exit(1); flock SELF, LOCK_EX | LOCK_NB or exit(0);

Recently I’ve found an interesting Perl web project – wikiCalc. Basically, it allows to build web pages which support limited functionality of spreadsheet. It might be interesting for developers who create various web-based user interfaces and want to expand them.