gistfile1.txt

Relevant URLS:

Full JSON dataset: option=com_gives&view=opportunities&format=json
Reduced JSON dataset: option=com_gives&view=opportunities&format=json&detail=short

json.php

<?php

class ComGivesViewOpportunitiesJson extends KViewJson
{
	
	public function display()
	{
		if(empty($this->output)) {
			$model = $this->getModel();
			$items = $model->getList()->toArray();
			$data = array();
			
			foreach ($items as $index=>$row) {
				$data[$index] = array_filter($row);
			}
            
			$this->output = json_encode($data);
                }

                return parent::display();
	}
}

opportunities.php

<?php

class ComGivesModelOpportunities extends ComDefaultModelDefault
{
	
	public function __construct(KConfig $config)
	{
		parent::__construct($config);
		
		$this->_state
			->insert('detail', 'cmd')
	}
	
	protected function _buildQueryColumns(KDatabaseQuery $query)
	{
		if (isset($this->_state->detail)) {
			if ($this->_state->detail === 'short') {
				$query->select(array(
					'tbl.gives_opportunity_id',
					'tbl.title',
				));
			}
		}
	}
	
}