PHP代码在远程服务器上不起作用

Question

I am having some trouble with a few lines of PHP code when I upload it to my domain over ftp. The lines below work on my local server on XAMPP but when I upload it to the remote server through my hosting client, instead of echoing out what it is supposed to, I get a blank page with no error log or message displayed. Any help would be greatly appreciated and thank you for taking the time to answer my question.

Code that doesn't work:

<?php

function getDominantColour($image, $type='png')
{


    eval('$source = imagecreatefrom' . $type . '("' . $image . '");'); 
    $source_x = imagesx($source); 
    $source_y = imagesy($source); 
    $resized_x = 100; 
    $resized_y = 100; 
    $resized= imagecreatetruecolor($resized_x, $resized_y); 
    imagecopyresampled($resized, $source, 0, 0, 0, 0, $resized_x, $resized_y, $source_x, $source_y);


    $colours = array();
    $rgb = '';
    $index = array();
    for ($x=0; $x<100; $x++) 
    {
        for ($y=0; $y<100; $y++)
        {
            $rgb = imagecolorat($resized, $x, $y); 
            $index = imagecolorsforindex($resized, $rgb); 
            $key = 'R' . $index['red'] . 'G' . $index['green'] . 'B' . $index['blue']; 
            if (empty($colours[$key])) 
            {
                $colours[$key] = 1;
            } else { 
                $colours[$key]++;
            }
        }
    }
    arsort($colours, SORT_NUMERIC);
    return key($colours);
}


echo(getDominantColour("http://maps.googleapis.com/maps/api/staticmap?center=40.727404,-74.020862&zoom=50&size=600x300&maptype=roadmap&markers=color:blue&sensor=false"));

?>

Answer 1

eval is evil ( not always ) . But in your example i would try to avoid it.

In your code you could use call_user_func instead:

$source = call_user_func( 'imagecreatefrom' . $type, $image );

As if on this question explained:

1. Sometimes eval is the only/the right solution.
2. For most cases one should try something else.
3. If unsure, goto 2.
4. Else, be very, very careful.

Answer 2

eval is banned from lots of servers as a security precaution. Rewrite your code so that you don't use that function.