当没有$ _REQUEST时，“if else声明”

Question

I am making a simple if and else statement to get value from a requested link my code is

if($_REQUEST['f_id']=='')
{
    $friend_id=0;
}
else
{
    $friend_id=$_REQUEST['f_id'];
}

and suppose the link is www.example.com/profile.php?f_id=3

now its simple as if the f_id is empty or with value either of the above if and else statement would run. but what is a user is just playing around with link and he removes the whole ?f_id=3 with link left to be opened with www.example.com/profile.php then how to detect that f_id dosen't exist and in that case redirect to a error page ?

Answer 1

you can use the isset() php function to test that:

if(!isset($_REQUEST) || $_REQUEST['f_id']=='')
{ 
   $friend_id=0; 
} 
else 
{ 
  $friend_id=$_REQUEST['f_id']; 
}