system/handlers/adminimporthandler.php

<?php
namespace Habari;

class AdminImportHandler extends AdminHandler
{
  public function get_import()
  {
    // First check for plugins that provide troublseome features
    $features_present = Plugins::provided();
    $troublemakers = array();
    $bad_features = array(
        'ping',
        'pingback',
        'spamcheck',
    );
    $unwanted_features = array_intersect_key($features_present, array_flip($bad_features));
    array_walk( $unwanted_features, function($item, $key ) use(&$troublemakers) {
      foreach( $item as $current ) {
        if( !in_array( $current, $troublemakers ) ) {
          $troublemakers[] = $current;
        }
      }
    });

    if( count( $troublemakers ) ) {
      $troublemakers = implode( ', ', $troublemakers );
      $msg = _t( 'Plugins that conflict with importing are active. To prevent undesirable consequences, please de-activate the following plugins until the import is finished: ' ) . '<br>';
      $msg .= $troublemakers;
      $this->theme->conflicting_plugins = $msg;
      Session::error( $msg );
    }

    // Now get on with creating the page
    $importer = isset( $_POST['importer'] ) ? $_POST['importer'] : '';
    $stage = isset( $_POST['stage'] ) ? $_POST['stage'] : '1';
    $step = isset( $_POST['step'] ) ? $_POST['step'] : '1';

//    $this->theme->enctype = Plugins::filter( 'import_form_enctype', 'application/x-www-form-urlencoded', $importer, $stage, $step );

    // filter to get registered importers
    $importers = Plugins::filter( 'import_names', array() );

    // filter to get the output of the current importer, if one is running
    if ( $importer == '' ) {
      $output = $this->get_form( $importers, $importer );
    }
    else {
      $output = Plugins::filter( 'import_stage', '', $importer, $stage, $step );
    }

    $this->theme->importer = $importer;
    $this->theme->stage = $stage;
    $this->theme->step = $step;
    $this->theme->importers = $importers;
    $this->theme->output = $output;

    $this->display( 'import' );

  }

  public function post_import()
  {
    if ( !isset( $_POST['importer'] ) ) {
      Utils::redirect( URL::get( 'display_import' ) );
    }

    $this->get_import();
  }

  public function get_form( $importers, $importer )
  {
    $form = new FormUI( 'import' );

    if( count( $importers ) == 0 ) {
      $form->append( FormControlStatic(' <p>' . _t( 'You do not currently have any import plugins installed.' ) . '</p>' ) );
      $form->append( FormControlStatic(' <p>' . _t( 'Please <a href="%1$s">activate an import plugin</a> to enable importing.', array( URL::get( 'display_plugins' ) ) ) . '</p>' ) );
    }
    else {
      $form->append( FormControlLabel::wrap( _t( 'Please choose the type of import to perform:' ),
        FormControlSelect::create( 'importer' )->set_options( array_combine( $importers, $importers ) )
      ));
      $form->append( FormControlSubmit::create( 'import' )->set_caption(  _t( 'Select' ) ) );
    }

    return $form->get();
  }

}