Write a custom plugin

Presentation

Portal plugins let you customize LemonLDAP::NG’s behavior.

Common use cases for plugins are:

  • Looking up session information in an additional backend
  • Implementing additional controls or steps during login
  • Adjusting the behavior of SAML, OIDC or CAS protocols to work around application bugs

Creating a plugin can be as simple as writing a short Perl module file and declaring it in your configuration. See below for an example.

Plugin API

Authentication entry points

You can now write a custom portal plugin that will hook in the authentication process:

  • beforeAuth: method called before authentication process
  • betweenAuthAndData: method called after authentication and before setting “sessionInfo” provisionning
  • afterData: method called after “sessionInfo” provisionning
  • endAuth: method called when session is validated (after cookie build)
  • authCancel: method called when user click on “cancel” during auth process
  • forAuthUser: method called for already authenticated users
  • beforeLogout: method called before logout

Generic entry points

If you need to call a method just after any standard method in authentication process, then use afterSub, for example:

use constant afterSub => {
    getUser => 'mysub',
};
sub mysub {
    my ( $self ,$req ) = @_;
    # Do something
    return PE_OK;
}

If you need to call a method instead any standard method in authentication process, then use aroundSub, for example:

use constant aroundSub => {
    getUser => 'mysub',
};
sub mysub {
    my ( $self, $sub, $req ) = @_;
    # Do something before
    my $ret = $sub->($req);
    # Do something after
    return $ret;
}

Hooks

New in version 2.0.10.

Your plugin can also register itself to be called at some points of interest within the main LemonLDAP::NG code.

Routes

The plugin can also define new routes and call actions on them.

See also Lemonldap::NG::Portal::Main::Plugin man page.

Configuration

The current LemonLDAP::NG configuration can be accessed in the $self->conf hash. This variable is only meant to be read. Don’t try changing its content, or Bad Things may happen.

You can set your own parameters in General Parameters » Plugins » Custom plugins » Additional parameters and reach them through customPluginsParams

sub my_function {
    my ($self, $req) = @_;

    # Get a standard LLNG option
    my $llng_logo = $self->conf->{portalMainLogo};

    # Get your custom LLNG option
    my $myvar = $self->conf->{customPluginsParams}->{myvar};
    }

Logs

You can use the $self->logger and $self->userLogger objects to log information during your plugin execution. Use logger for technical logs and userLogger for accounting and tracability events.

sub my_function {
    my ($self, $req) = @_;

    $self->logger->debug("Debug message");
    if (my_custom_test($req->user)) {
        $self->userLogger->debug("User ". $req->user .
            " is not allowed because XXX");

        return PE_ERROR;
    }
    return PE_OK;
}

Remembering data

In order to remember data between different steps, you can use the $req->data hash.

Data will not be remembered in between requests, only in between methods that process the same HTTP request.

History management

Plugins may declare additional session fields to be stored in the Login History.

sub init {
    my ($self) = @_;

    $self->addSessionDataToRemember({
        # This field will be hidden from the user
        _language => '__hidden__',

        # This field will be displayed on the portal. The column name
        # is treated like a message and can be internationalized
        authenticationLevel => "Human friendly column name",
    });
    return 1;
}

Column names can be translated by overriding the corresponding message

Example

Plugin Perl module

This example creates a Lemonldap::NG::Portal::MyPlugin plugin that showcases some features of the plugin system.

First, create a file to contain the plugin code

vi /usr/share/perl5/Lemonldap/NG/Portal/MyPlugin.pm

Tip

If you do not want to mix files from the distribution with your own work, put your own code in /usr/local/lib/site_perl/Lemonldap/NG/Portal/MyPlugin.pm. Or you can use your own namespace such as ACME::Corp::MyPlugin.

# The package name must match the file path
# This file must be in Lemonldap/NG/Portal/MyPlugin.pm
package Lemonldap::NG::Portal::MyPlugin;

use Mouse;
use Lemonldap::NG::Portal::Main::Constants;
extends 'Lemonldap::NG::Portal::Main::Plugin';

# Declare when LemonLDAP::NG must call your functions
use constant beforeAuth => 'verifyIP';
use constant hook => { passwordAfterChange  => 'logPasswordChange' };

# This function will be called at the "beforeAuth" login step
sub verifyIP {
          my ($self, $req) = @_;
          return PE_ERROR if($req->address !~ /^10/);
          return PE_OK;
}

# This function will be called when changing passwords
sub logPasswordChange {
    my ( $self, $req, $user, $password, $old ) = @_;
    $self->userLogger->info("Password changed for $user");
    return PE_OK;
}

# You can define your custom initialization in the
# init method.
# Before LemonLDAP::NG 2.0.14, this function was mandatory
sub init {
          my ($self) = @_;

          # This is how you declare HTTP routes
          $self->addUnauthRoute( mypath => 'hello', [ 'GET', 'PUT' ] );
          $self->addAuthRoute( mypath => 'welcome', [ 'GET', 'PUT' ] );

          # The function can return 0 to indicate failure
          return 1;
}

# This method will be called to handle unauthenticated requests to /mypath
sub hello {
          my ($self, $req) = @_;
          ...
          return $self->p->sendJSONresponse($req, { hello => 1 });
}

# This method will be called to handle authenticated requests to /mypath
sub welcome {
          my ($self, $req) = @_;

          my $userid = $req->user;
          $self->p->logger->debug("Call welcome for $userid");

          ...
          return $self->p->sendHtml($req, 'template', params => { WELCOME => 1 });
}

# Your file must return 1, or Perl will complain.
1;

Enabling your plugin

Declare the plugin in lemonldap-ng.ini:

vi /etc/lemonldap-ng/lemonldap-ng.ini
[portal]
customPlugins = Lemonldap::NG::Portal::MyPlugin
;customPlugins = Lemonldap::NG::Portal::MyPlugin1, Lemonldap::NG::Portal::MyPlugin2, ...

Since 2.0.7, it can also be configured in Manager, in General Parameters > Plugins > Custom Plugins.