Codeigniter database check - codeigniter

Question

i am currently working on a project where users can save note snippets in there own little user area.
I was wondering how would i check if the id of an item exists for example if a user visits
http://mysite.com/view/1 and there is a note snippet of 1 it will display all the data relating to the id of one. Now if the user was to change the url to lets say 1000, that id doesnt exist and the view just errors.
i want to be able to redirect them back to a certain page with a error message "snippet does not exist" etc.
heres what i have so far ( i currently already have a conditional statement in here to check if the snippet is private, then if it is redirect back to /publicsnippets)
Controller:
class Publicsnippets extends CI_Controller {
function __construct()
{
parent::__construct();
if (!$this->tank_auth->is_logged_in()) {
redirect('/login/');
}
$this->load->model('dashboard_model');
$this->data['user_id'] = $this->tank_auth->get_user_id();
$this->data['username']= $this->tank_auth->get_username();
}
public function index()
{
$this->data['public_snippets'] = $this->dashboard_model->public_snippets();
$this->load->view('dashboard/public_snippets', $this->data);
}
public function view($snippet_id)
{
$snippet = $this->dashboard_model->get_snippet($snippet_id);
if ($snippet['state'] === 'private')
{
$this->session->set_flashdata('message', "<b style=\"color:red;\">You are not allowed to view this snippet!</b>");
redirect('/publicsnippets');
} else {
$this->data['snippet'] = $snippet;
}
$this->load->view('dashboard/view_public_snippet', $this->data);
}
}
Model:
class Dashboard_model extends CI_Model {
public function public_snippets()
{
$this->db->select('id, title, description, tags, author, date_submitted');
$query = $this->db->get_where('snippets', array('state' => 'public'));
return $query->result_array();
}
public function private_snippets()
{
$this->db->select('id, title, description, tags, author, date_submitted');
$query = $this->db->get_where('snippets', array('user_id' => $this->tank_auth->get_user_id()));
return $query->result_array();
}
public function add_snippet($data)
{
$this->db->insert('snippets', $data);
$id = $this->db->insert_id();
return (isset($id)) ? $id : FALSE;
}
public function get_snippet($snippet_id) {
$query = $this->db->get_where('snippets', array('id' => $snippet_id));
return $query->row_array();
}
public function update_snippet($snippet_id, $data)
{
$this->db->where('id', $snippet_id);
$this->db->update('snippets', $data);
}
public function delete_snippet($snippet_id)
{
$this->db->where('id', $snippet_id);
$this->db->delete('snippets');
}
}
View:
<h3>Description</h3>
<p><?php echo $snippet['description']; ?></p>
<h3>Tags</h3>
<p><?php echo $snippet['tags']; ?></p>
<h3>Date Submitted</h3>
<p><?php echo $snippet['date_submitted']; ?></p>
<h3>Snippet</h3></pre>
<pre class="prettyprint"><?php echo $snippet['code_snippet']; ?></pre>

Answer 1

You work is fine just add a check like this in your view method
Controller
public function view($snippet_id)
{
$snippet = $this->dashboard_model->get_snippet($snippet_id);
if($snippet){
if ($snippet['state'] === 'private')
{
$this->session->set_flashdata('message', "<b style=\"color:red;\">You are not allowed to view this snippet!</b>");
redirect('/publicsnippets');
} else {
$this->data['snippet'] = $snippet;
}
$this->load->view('dashboard/view_public_snippet', $this->data);
}else{
$this->session->set_flashdata('message', "<b style=\"color:red;\">snippet does not exist</b>");
redirect('/publicsnippets');
}
}
if no row is found in get_snippet method the $snippet will contain false or null
and the second block of condition will run.

Answer 2

In your model change get_snippet() to check for rows:
public function get_snippet($snippet_id) {
$query = $this->db->get_where('snippets', array('id' => $snippet_id));
if ($query->num_rows() > 0) {
return $query->row_array();
} else {
return false;
}
}
Then in your controller:
if ($snippet = $this->dashboard_model->get_snippet($snippet_id)) {
// code if snippet exists
} else {
// code if snippet doesn't exist
}
OR
$snippet = $this->dashboard_model->get_snippet($snippet_id);
if ($snippet) {
// etc...