php activerecord save does not work in codeigniter - php

Question

I use the latest code igniter (2.0.3) and php-active 0.0.1.
All are working fine except save();
Code:
if($_POST)
{
$entry= Customers::find_by_routeid('4');
$entry->routeid=5;
$entry->save();
}
Here's my problem: for some reason that I cannot understand the above code does not work, but if I take the code out of if ($_POST), it works fine.
What I am doing wrong?
EDIT:
Thanks Damien Pirsy $this->input->post() does the trick, but when I uncomment the comments in the code the problems returns.
The code now is:
if($this->input->post())
{
$id = $this->input->post('id');
$oldRoute = $this->input->post('oldRoute');
$newRoute = $this->input->post('newRoute');
$entry= Customers::find_by_routeid($this->input->post('oldRoute'));
$entry->routeid=$this->input->post('newRoute');
$entry->save();
/*
if($oldRoute<$newRoute)
{
for ($i=$newRoute; $i>$oldRoute; $i--)
{
$element = Customers::find_by_routeid($i);
echo $element->routeid -= 1;
$element->save();
}
}
*/
}
The elements new IDs ($element->routeid -= 1;) are echoing right, but I have the same problem as in the beginning and neither of two saves work.

Answer 1

You didn't provide much details or debug info, so I'll just guess: try using the CI's native post handler instead. You should have var_dump()ed the $_POST array, see if isset() or not, also, since you're using it as a condition
if($this->input->post())
{
//...
}
UPDATE:
Since we're talking about Post variables, don't assume they're exactly as you want them. Keep in mind that $this->input->post('field') returns FALSE when the index is not present; that might well brake your if condition.
Assuming you need numbers to do this, you can do a check like
if($this->input->post('newRoute') AND is_numeric($this->input->post('newRoute'))
{
$newRoute = $this->input->post('newRoute');
}
else
{
// give it a default value, or raise an error, for example. If you need this
// variables, and need them to be numbers, you cannot go on in case these
// conditions are not met, right?
}
And the same for $oldRoute.
And yeah, OK, maybe you can write a cleaner code than mine, but you get the picture ;)