上传JPG，但不上传jpg

Question

我有一个代码块上传一个图像，并创建一个缩略图，只要扩展是小写jpg，但它不会上传一个图像，如果它是大写的JPG。当我重命名图像，例如example.jpg到example.JPG时，它就会上传。但是example.JPG不会上传，我也不会收到错误。这对我来说没有任何意义。有人对此有解释吗？这是我的代码：

<?php
function createThumbnail($filename) {
  require 'config.php';

  if(preg_match('/[.](jpg)$/', $filename)) {
    $im = imagecreatefromjpeg($filename.$path_to_image_directory);
  } else if (preg_match('/[.](gif)$/', $filename)) {
    $im = imagecreatefromgif($path_to_image_directory . $filename);
  } else if (preg_match('/[.](png)$/', $filename)) {
    $im = imagecreatefrompng($path_to_image_directory . $filename);
  }

  $ox = imagesx($im);
  $oy = imagesy($im);

  $nx = $final_width_of_image;
  $ny = $final_height_of_image;

  $nm = imagecreatetruecolor($nx, $ny);

  imagecopyresampled($nm, $im, 0,0,0,0,$nx,$ny,$ox,$oy);

  if(!file_exists($path_to_thumbs_directory)) {
    if(!mkdir($path_to_thumbs_directory)) {
       die("There was a problem. Please try again!");
    } 
  }

  imagejpeg($nm, $path_to_thumbs_directory . $filename);
  $tn = '<img src="' . $path_to_thumbs_directory . $filename . '" alt="image" />';
  $tn .= '<br />Congratulations. Your file has been successfully uploaded, and a      thumbnail has been created.';
  echo $tn;
}
?>

配置文件：

<?php  
$final_width_of_image = 300;
$final_height_of_image = 300;
$path_to_image_directory = '';
$path_to_thumbs_directory = '-tn';
?>     

Answer 1

在这个代码块中，您只允许小写文件扩展名：

if(preg_match('/[.](jpg)$/', $filename)) {
//--lowercase-only--^ 
    $im = imagecreatefromjpeg($filename.$path_to_image_directory);
}else if (preg_match('/[.](gif)$/', $filename)) {
    $im = imagecreatefromgif($path_to_image_directory . $filename);
} else if (preg_match('/[.](png)$/', $filename)) {
    $im = imagecreatefrompng($path_to_image_directory . $filename);
}

您可以通过在regex中放置一个或条件来修复：

if(preg_match('/[.](jpg|JPG)$/', $filename)) {
// -----uppercase-------^
    $im = imagecreatefromjpeg($filename.$path_to_image_directory);
}else if (preg_match('/[.](gif|GIF)$/', $filename)) {
    $im = imagecreatefromgif($path_to_image_directory . $filename);
} else if (preg_match('/[.](png|PNG)$/', $filename)) {
    $im = imagecreatefrompng($path_to_image_directory . $filename);
}

也可以使用i修饰符添加不区分大小写：

if(preg_match('/[.](jpg)$/i', $filename)) {
// -------modifier--------^ 
    $im = imagecreatefromjpeg($filename.$path_to_image_directory);
}else if (preg_match('/[.](gif)$/i', $filename)) {
    $im = imagecreatefromgif($path_to_image_directory . $filename);
} else if (preg_match('/[.](png)$/i', $filename)) {
    $im = imagecreatefrompng($path_to_image_directory . $filename);
}

Answer 2

更好的方法是检查文件本身，而不是扩展名，这可能总是错误的。

    $data = getimagesize($filename);
    switch($data['mime]){
        case('image/png):
            $im = imagecreatefrompng($filename);
            break;
        case('img/jpg'):
        case('image/jpeg'):
        case('image/pjpeg'):
        case('image/x-jps'):
            $im = imagecreatefromjpeg($filename);
            break;
        case(self::GIF):
            $im = imagecreatefromgif($filename);
            break;
    }