PHP警告：strpos（）：search.php中的空针

Question

I have a php search file that searches a directory for files with the submitted names and displays the results. I want to use the html form in the same file as the php code i.e., in search.php only like this:

<form action="search.php" method="get"><input name="q"
type="text"> <input type="submit"></form>

<?php
$dir = '/www/posts'; 
$exclude = array('.','..','.htaccess'); 
$q = (isset($_GET['q']))? strtolower($_GET['q']) : ''; 
$res = opendir($dir);

while(false!== ($file = readdir($res))) { 
    if(strpos(strtolower($file),$q)!== false &&!in_array($file,$exclude)) 
    { 
        $last_dot_index = strrpos($file, ".");
        $withoutExt = substr($file, 0, $last_dot_index);
        echo "<a href='$withoutExt'>$withoutExt</a>"; 
        echo "<br>"; 
    }
}  
closedir($res); 
?>

But the above code gives the error : Warning: strpos(): Empty needle in search.php on line 10

I tried using the !empty argument like this:

<?php
$dir = '/www/posts'; 
$exclude = array('.','..','.htaccess'); 
$q = (isset($_GET['q']))? strtolower($_GET['q']) : ''; 
$res = opendir($dir);

if (!empty($res)) {
    while(false!== ($file = readdir($res))) { 
         if(strpos(strtolower($file),$q)!== false &&!in_array($file,$exclude)) { 
             $last_dot_index = strrpos($file, ".");
             $withoutExt = substr($file, 0, $last_dot_index);
             echo "<a href='$withoutExt'>$withoutExt</a>"; 
             echo "<br>"; 
         }
         else {
             echo "";
         }
     }
}  
closedir($res); 
?>

But it still reflects the error.

Please help me get rid of this error.

Answer 1

You need to check $q for emptiness. If it's empty - what's the point to search. There's even no need to run opendir if $q is empty.

if (!empty($q)) {
    $res = opendir($dir);
    while(false!== ($file = readdir($res))) { 
        // more codes here