Sending a function to library in Codeigniter - php

Question

This works in my controller.
$this->load->driver('cache');
//working
// $data['advisory']=$advisory = $this->cache->memcached->get('advisory');
// if(! $advisory)
// {
// $data['advisory']=$advisory = $this->Mhomework->getbyadvisory($this->teacherid);
// $this->cache->memcached->save('advisory' , $advisory);
// }
I made a library to make for this as following so that I can use it for others.
function cache($key, $data)
{
$this->CI->load->driver('cache');
$cache = $this->CI->cache->memcached->get($key);
if (!$cache) {
// There's been a miss, so run our data function and store it
$cache = $data($CI);
//$cache = $data;
$this->CI->cache->memcached->save($key, $cache);
}
return $cache;
}
And in controller I changed to the following which gives an error.
$data['advisory'] = $this->hwtracker->cache('advisory.'.$this->teacherid, function(&$CI){
return $CI->Mhomework->getbyadvisory($this->teacherid);
});
// error Call to a member function getbyadvisory() on a non-object in ... controller
// Message: Trying to get property of non-object
My question is how I can send function to my library in CodeIgniter? Or Can I?
Update:　　　　
function getbyadvisory($id){
　　$Q="SELECT *, studentid, COUNT(studentid),be_user_profiles.first_name, 　　
　　　　　　　be_user_profiles.last_name
FROM be_user_profiles
LEFT JOIN hw_homework
ON be_user_profiles.user_id= hw_homework.studentid
WHERE be_user_profiles.advisor = $id
GROUP BY be_user_profiles.user_id
ORDER BY COUNT(studentid) DESC";
$query = $this->db->query($Q);
if ($query->num_rows() > 0)
{
foreach ($query->result_array() as $row)
{
$data[] = $row;
}
}
else
{
$data = FALSE;
}
$query->free_result();
return $data;
}

Answer 1

Please change your library to be like this
function cache($key, $data)
{
$this->CI->load->driver('cache');
//bind your key here
$key_details = $data.$key;
$cache = $this->CI->cache->memcached->get($key_details);
if (!$cache) {
// There's been a miss, so run our data function and store it
$cache = $this->$data($key);
//$cache = $data;
$this->CI->cache->memcached->save($key, $cache);
}
return $cache;
}
//new advisory function in library
function advisory($teacherid){
return $this->CI->Mhomework->getbyadvisory($teacherid);
}
And in controller call like this
$data['advisory'] = $this->hwtracker->cache($this->teacherid,'advisory');