problems with array in codeigniter - php

Question

I want to insert my notifications static , but I'm checking the variable type is not empty, but at the moment insert says Message: Illegal string offset 'notificationCount' and Undefined index: type. I'm trying to make my array dynamically, but it doesn't seem to work.
public function addNotification($message, $product_id, $type = ''){
$types = array('new' => 0, 'pending' => 1, 'low stock' => 3);
if (isset($types[$type]) === false) {
throw new \InvalidArgumentException('Value for third parameter must be one of new, pending, or low stock.');
}
$type = $types[$type];
$time = time();
$query = "SELECT COUNT(*) AS notificationCount FROM storelte_notifications WHERE product_id = ? AND type = ? ";
$previousNotification = $this->db->query($query, array($product_id, $type));
if ($previousNotification[0]['notificationCount'] == 0) {
$sql = "INSERT INTO storelte_notifications (message,type,product_id,created_at) VALUES(?, ?, ?, ?)";
$this->db->query($sql, array($message, $type, $product_id, $time));
try {
if ($this->db->query($sql)) {
return true;
}else{
return false;
}
} catch (Exception $e) {
}
}else{
return true;
}
}
controller
public function add(){
$this->notification->addNotification('low stock',4228,'type');
}

Answer 1

$sql_prev_notification is a string that you've created here:
$sql_prev_notification = "SELECT COUNT(*) AS notificationCount FROM storelte_notifications WHERE product_id = ? AND type = ? ";
You use it to execute a query with:
$this->db->query($sql_prev_notification, array($product_id, $type));
but you haven't assigned the returned results of the query to anything.
$sql_prev_notification is still a string, so when you do this:
if ($sql_prev_notification[0]['notificationCount'] == 0) {
$sql_prev_notification[0] is referring to the first letter in the string (S), which obviously isn't an array, hence the
Illegal string offset 'notificationCount'
You probably want something more like:
$sql = "SELECT COUNT(*) AS notificationCount FROM storelte_notifications WHERE product_id = ? AND type = ? ";
$sql_prev_notification = $this->db->query($sql, array($product_id, $type));
if ($sql_prev_notification[0]['notificationCount'] == 0) {
although you should also be checking if your query actually returns anything before referring to a specific item from its results.

Answer 2

Don't Panic's answer (https://stackoverflow.com/a/43529550/4132627) is the right one to fix the illegal string offset, go with that.
For the error Undefined index: type, it would appear that you are passing the string "type" as the value for the variable $type. It then uses that value as a key for the $types array, but the $types array doesn't have an index "type" - its indexes are "new", "pending", and "low stock".
To fix this, you have to pass either "new", "pending", or "low stock" as the third parameter to your addNotification function:
$this->notification->addNotification('low stock',4228,'new');
//or
$this->notification->addNotification('low stock',4228,'pending');
//of
$this->notification->addNotification('low stock',4228,'low stock');
You should also check that the key passed is valid, otherwise you will continue to get this notice. In fact, passing the wrong value probably causes your code to function irregularly, in which case throwing an exception is probably a good idea:
if (isset($types[$type]) === false) {
throw new \InvalidArgumentException('Value for third parameter must be one of new, pending, or low stock.');
}
$type = $types[$type];

Answer 3

You can try this:
public function addNotification( $message, $product_id, $type = '' ){
$types = array( 'new' => 0, 'pending' => 1, 'low stock' => 3);
if (isset($types[$type]) === false) {
throw new \InvalidArgumentException('Value for third parameter must be one of new, pending, or low stock.');
}
$type = $types[$type];
$time = time();
$this->db->select_sum('notificationCount');
$this->db->where(['product_id' => $product_id, 'type' => $type]);
$query = $this->db->get();
$previousNotification = $query->row_array()
if ( $previousNotification['notificationCount'] == 0 ) {
$this->db->trans_start();
$this->db->insert(storelte_notifications, ['message' => $message, 'type' => $type, 'product_id' => $product_id, 'created_at' => $time]);
$this->db->trans_complete();
return $this->db->trans_status();
} else {
return true;
}
}