How to access the APIv3 from wordpress plugin files

Question

I'm developing a little wordpress plugin which creates a custom post type with a custom field where I would like to store an ID of one of the active contribution page of CiviCRM in order to associate this content with the contribution page information.

This very same code works in theme files but fails when is used in plugin files, breaking the site.

   function get_contribution_info($f_type){
   $params = array(
       'version'    =>  3,
        'financial_type_id' => $f_type,
        'is_active' => '1'
    );
    try{
       $result = civicrm_api3('contribution_page', 'get', $params);
    } catch (CiviCRM_API3_Exception $e) {
        // handle error here
        $errorMessage = $e->getMessage();
        $errorCode = $e->getErrorCode();
        $errorData = $e->getExtraParams();
        return array('error' => $errorMessage, 'error_code' => $errorCode, 'error_data' => $errorData);
    }
    return $result[values];
    }

    $get_contrib = get_contribution_data( '1' );
    $contributions = array();
    $i = 0;
    foreach($get_contrib as $c) {
        $contributions[$i]['label'] = $c['title'];
        $contributions[$i]['value'] = $c['id'];
        $i++;
    }

I've tried to add a require_once the class.api.php without positive results.

Thanks in advance for your help!

Answer 1

Try prefixing your API call with:

civicrm_initialize();

The "class.api.php" is for when you want to use the REST API from an external site.

Answer 2

Solved!!!

   function get_contribution_info($f_type){

   $params = array(
       'version'    =>  3,
       'financial_type_id' => $f_type,
       'is_active' => '1'
   );
   try{
       if ( ! function_exists( 'civicrm_initialize' ) ) { return; }
       civicrm_initialize();
       $result = civicrm_api3('contribution_page', 'get', $params);
   } catch (CiviCRM_API3_Exception $e) {
       // handle error here
       $errorMessage = $e->getMessage();
       $errorCode = $e->getErrorCode();
       $errorData = $e->getExtraParams();
       return array('error' => $errorMessage, 'error_code' => $errorCode, 'error_data' => $errorData);
    }
   return $result[values];
}

The key was on adding civicrm_initialize();. Thanks to @bgm for the advice!