Extending the OTOBO Core System Internally

In this article, you will learn how to customize OTOBO directly in its core – via XML configuration, Perl modules, and templates. We'll show you step-by-step how to integrate your own "HelloWorld" module into the system.

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1. Directory Structure

All customizations are located within your OTOBO clone in the Kernel/ directory:

Kernel/
├─ Config/Files/           # XML registrations
│  └─ XML/
├─ System/                 # Business logic modules (Core)
├─ Modules/                # Frontend controllers (Agent/Customer)
├─ Output/HTML/Standard/   # Template Toolkit (TT) templates
└─ Language/               # Translations

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2. XML Configuration

New modules and routes are registered via XML. Create a file named HelloWorld.xml in Kernel/Config/Files/XML/:

<?xml version="1.0" encoding="UTF-8"?>
<otobo_config version="2.0" init="Application">

  <!-- 1. Register frontend module -->
  <Setting Name="Frontend::Module###AgentHelloWorld" Required="1" Valid="1">
    <Navigation>Frontend::Agent::ModuleRegistration</Navigation>
    <Value>
      <Item ValueType="FrontendRegistration">
        <Hash>
          <Item Key="Group"><Array><Item>users</Item></Array></Item>
          <Item Key="Description" Translatable="1">HelloWorld Module</Item>
          <Item Key="Title"       Translatable="1">HelloWorld</Item>
          <Item Key="NavBarName">HelloWorld</Item>
        </Hash>
      </Item>
    </Value>
  </Setting>

</otobo_config>

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3. Core Module (Business Logic)

Create your logic in Kernel/System/HelloWorld.pm:

package Kernel::System::HelloWorld;
use strict;
use warnings;
our @ObjectDependencies = ();  

sub new {
    my ($Type, %Param) = @_;
    return bless {}, $Type;
}

sub GetHelloWorldText {
    my ($Self, %Param) = @_;
    return $Self->_FormatText(String => 'Hello World');
}

sub _FormatText {
    my ($Self, %Param) = @_;
    return uc $Param{String};
}

1;

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4. Frontend Module (Controller)

In Kernel/Modules/AgentHelloWorld.pm, you integrate your logic into the agent frontend:

package Kernel::Modules::AgentHelloWorld;
use strict;
use warnings;

sub new { bless {}, shift }

sub Run {
    my ($Self, %Param) = @_;

    my $HelloObj    = $Kernel::OM->Get('Kernel::System::HelloWorld');
    my $LayoutObj   = $Kernel::OM->Get('Kernel::Output::HTML::Layout');
    my %Data;
    
    $Data{Text} = $HelloObj->GetHelloWorldText();

    return 
        $LayoutObj->Header(Title => 'HelloWorld')
      . $LayoutObj->NavigationBar()
      . $LayoutObj->Output(
          TemplateFile => 'AgentHelloWorld',
          Data         => \%Data,
        )
      . $LayoutObj->Footer();
}

1;

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5. Templates (TT)

Create the following template in Kernel/Output/HTML/Standard/AgentHelloWorld.tt:

[% Data.Text %]

<p>This is your self-created HelloWorld module!</p>

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6. Example Workflow

1. Reload:

   bin/otobo.Console.pl Maint::Config::Rebuild

2. Clear cache:

   bin/otobo.Console.pl Maint::Cache::Delete

3. Open browser: Agent interface → Menu → "HelloWorld"

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7. Tips & Best Practices

• Declare ObjectDependencies cleanly (e.g., DB, Layout).
• Don't forget POD documentation in Perl modules.
• Maintain translations under Kernel/Language/de_*.pm.
• Set up unit tests with Mojolicious (optional).
• After every change, rebuild config & delete cache.

With this, you have a solid template for implementing further core extensions in OTOBO. Happy coding