Php 文件上传不'；t检查现有图像

我从整洁的设计中得到了下面的代码，它运行良好，只是没有检查现有的图像。当我再次上传同一张图片时，它接受了，没有任何错误。我发现脚本在上传到新的随机名称后会重新命名文件，它还试图查看保存图像的文件夹中是否存在新名称。这意味着它将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？我是否需要删除重命名上传图像的功能

     <?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>

---

您不需要删除任何代码，只需更改调用函数的方式即可

该功能定义为：

函数上传文件（$file\u field=null，$check\u image=false，$random\u name=false）

您可以看到

$random\u name

变量作为参数传递给函数。如果设置为

true

，则为上载的图像设置随机文件名

您这样调用函数：

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

因此，您可以看到正在传递的第三个参数（即对应于

$random\u name

的参数是

true

）

试着把它改成

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

---

阻止函数强制文件具有随机文件名。

我应该在哪里更改它？我所做的是将null和false更改为file和true。这就是你的意思吗？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-在在我的回答中建议确切位置？我仍然很困惑。//创建完整的文件名，包括路径if（$random_name）…这就是调用函数的地方。那么我应该更改什么？不，那不是调用函数的地方。将此行更改为

$file=uploadFile（'file'，true，true）；

为

$file=uploadFile（'file'，true，false）；

。它位于代码的底部。为了给您澄清，“函数”是

uploadFile