文件上传不检查现有图像

Posted 2023-02-23

【中文标题】文件上传不检查现有图像

【英文标题】：file upload doesn't check for existing image

【发布时间】：2013-01-25 11:29:34

【问题描述】：

我从 tidy-designs 获得了以下代码，它工作正常，只是它不检查现有图像。当我再次上传相同的图像时，它会毫无错误地接受。我发现脚本在上传到新的随机名称后重命名文件，并且它还试图查看新名称是否存在于保存图像的文件夹中。这意味着它为每个上传的图像提供新的随机名称，并尝试检查新名称是否存在。如何检查现有图像？我需要删除重命名上传图片的功能吗？

     <?php

function uploadFile ($file_field = null, $check_image = false, $random_name = false) 

//Config Section    
//Set file upload path
$path = 'productpic/'; //with trailing slash
//Set max file size in bytes
$max_size = 2097152;
//Set default file extension whitelist
$whitelist_ext = array('jpg','png','gif');
//Set default file type whitelist
$whitelist_type = array('image/jpeg', 'image/png','image/gif');

//The Validation
// Create an array to hold any output
$out = array('error'=>null);

if (!$file_field) 
$out['error'][] = "Please specify a valid form field name";           


if (!$path) 
$out['error'][] = "Please specify a valid upload path";               


if (count($out['error'])>0) 
return $out;


//Make sure that there is a file
if((!empty($_FILES[$file_field])) && ($_FILES[$file_field]['error'] == 0)) 

// Get filename
$file_info = pathinfo($_FILES[$file_field]['name']);
$name = $file_info['filename'];
$ext = $file_info['extension'];

//Check file has the right extension           
if (!in_array($ext, $whitelist_ext)) 
  $out['error'][] = "Invalid file Extension";


//Check that the file is of the right type
if (!in_array($_FILES[$file_field]["type"], $whitelist_type)) 
  $out['error'][] = "Invalid file Type";


//Check that the file is not too big
if ($_FILES[$file_field]["size"] > $max_size) 
  $out['error'][] = "We are sorry, the image must be less than 2MB";


//If $check image is set as true
if ($check_image) 
  if (!getimagesize($_FILES[$file_field]['tmp_name'])) 
    $out['error'][] = "The file you trying to upload is not an Image, we only accept images";
  


//Create full filename including path
if ($random_name) 
  // Generate random filename
  $tmp = str_replace(array('.',' '), array('',''), microtime());

  if (!$tmp || $tmp == '') 
    $out['error'][] = "File must have a name";
       
  $newname = $tmp.'.'.$ext;                                
 else 
    $newname = $name.'.'.$ext;


//Check if file already exists on server
if (file_exists($path.$newname)) 
  $out['error'][] = "the image you trying to upload already exists, please upload only once";


if (count($out['error'])>0) 
  //The file has not correctly validated
  return $out;
 

if (move_uploaded_file($_FILES[$file_field]['tmp_name'], $path.$newname)) 
  //Success
  $out['filepath'] = $path;
  $out['filename'] = $newname;
  return $out;
 else 
  $out['error'][] = "Server Error!";


 else 
$out['error'][] = "No image uploaded";
return $out;
      

?>

<?php
if (isset($_POST['submit'])) 
$file = uploadFile('file', true, true);
if (is_array($file['error'])) 
$message = '';
foreach ($file['error'] as $msg) 
  $message .= '<p>'.$msg.'</p>';    

 else 
$message = "File uploaded successfully";

echo $message;

?>
<form action="" method="post" enctype="multipart/form-data" name="form1" id="form1">
<input name="file" type="file" size="20" />
<input name="submit" type="submit" value="Upload" />
</form>

【参考方案1】：

您无需删除任何代码 - 只需更改调用函数的方式即可。

函数定义为：

function uploadFile ($file_field = null, $check_image = false, $random_name = false)

您可以看到$random_name 变量作为参数传递给函数。如果设置为true，它将为上传的图像设置一个随机文件名。

你是这样调用函数的：

$file = uploadFile('file', true, true);

所以你可以看到你传递的第三个参数（即对应$random_name参数是true。

尝试将其更改为

$file = uploadFile('file', true, false);

阻止函数强制文件具有随机文件名。

【讨论】：

我应该在哪里改变它？我所做的是将 null 和 false 更改为 file 和 true。你是这个意思吗？我有点困惑。即使这样做也不会检查。谢谢

不要更改函数定义，更改调用函数的位置 - 进行我在回答中建议的更改

具体在哪里？我仍然很困惑。 //创建完整的文件名，包括路径 if ($random_name) ... 那就是函数被调用的地方.. 那我应该改变什么？

不，这不是函数被调用的地方。将此行 $file = uploadFile('file', true, true); 更改为 $file = uploadFile('file', true, false);。它位于代码的底部。

为你澄清一下，“函数”是uploadFile