文件上传Deny动画GIF（使用PHP/Zend框架）

Question

我想我可能希望用户能够上传静态GIF但不是动画的。对于虚拟形象来说，因为他们可能看起来......不专业和分心。有没有在PHP或Zend框架的方式，我可以验证文件上传的方式？

Answer 1

您可以使用gd库来保存图像。使用gif类型的文件只保存来自gif文件的第一帧，如果它动画。有关如何使用它的更多信息，请参阅imagegif函数。

Answer 2

形式的PHP: imagecreatefromgif - Manual：

I wrote two alternate versions of ZeBadger's is_ani() function, for determining if a gif file is animated 

Original: 
http://us.php.net/manual/en/function.imagecreatefromgif.php#59787 

The first alternative version is just as memory intensive as the original, and more CPU intensive, but far simpler: 

<?php 
function is_ani($filename) { 
    return (bool)preg_match('#(\x00\x21\xF9\x04.{4}\x00\x2C.*){2,}#s', file_get_contents($filename)); 
} 
?> 

The second alternative is about as CPU intensive as the original function, but uses less memory (and may also result in less disk activity) 

<?php 
function is_ani($filename) { 
    if(!($fh = @fopen($filename, 'rb'))) 
     return false; 
    $count = 0; 
    //an animated gif contains multiple "frames", with each frame having a 
    //header made up of: 
    // * a static 4-byte sequence (\x00\x21\xF9\x04) 
    // * 4 variable bytes 
    // * a static 2-byte sequence (\x00\x2C) 

    // We read through the file til we reach the end of the file, or we've found 
    // at least 2 frame headers 
    while(!feof($fh) && $count < 2) 
     $chunk = fread($fh, 1024 * 100); //read 100kb at a time 
     $count += preg_match_all('#\x00\x21\xF9\x04.{4}\x00\x2C#s', $chunk, $matches); 

    fclose($fh); 
    return $count > 1; 
} 
?>