PHP：当用户上传带有不允许的扩展名的图像时，文件扩展名为空

Pancake_M0nster 发表于 Dev

Pancake_M0nster

我的网站上有一个表格，除其他所有内容外，它还允许用户将图像上传到网站。HTML和PHP：

<html>
<body>
<?php  
if($_SERVER['REQUEST_METHOD'] == 'POST'){
  $error = '';

  // Checking other input fields...

  // If anything else is valid, try to upload file (to avoid uploading useless c**p)
  if(isset($_FILES['file']) && $error == '' && $_FILES['file']){
    $file = $_FILES['file'];
    $file_name = $file['name'];
    $file_tmp = $file['tmp_name'];
    $file_size = $file['size'];
    $file_error = '';
    echo $file . $file_name . $file_tmp . $file_size;
    $file_ext = pathinfo($file_name, PATHINFO_EXTENSION);
    if($file_ext != 'png' && $file_ext != 'jpg' && $file_ext != 'jpeg' && $file_ext != 'gif' && $file_ext != 'bmp'){
      $file_error .= "<br>Only png, jpg, jpeg, gif and bmp formats allowed!";
    }
    if($file_size > 1048576){ // << 1MB in bytes
      $file_error .= "<br>Maximum size is 1MB.";
    }
    if(empty($file_error)){
      $file_name_new = uniqid('', true) . '.' . $file_ext;
      $file_destination = 'img/usr/' . $file_name_new;
      if(rename($file_tmp, $file_destination)){
        // echo '<br>' . $file_destination;
      } else{$file_error .= '<br>Something went wrong while uploading file';}
    }
    echo $file_error;
  }
}
?>
  <form method="post" action="" enctype="multipart/form-data">
    <fieldset>
      <legend>Form</legend>
      <!-- Other input fields -->
      <div id="form_element">Upload image:</div>
      <input type="file" name="file"><span id="error"><small><?php echo $file_error;
  //echo $file . '<br>' .  $_FILES['file'] . '<br>' . $file_name . $file['name'];
  //echo '<br>' .  $file_tmp . '<br>' . $file['tmp_name'] . '<br>' . $file_size . '<br>' . $file['size'];
  ?></small></span>
      <div id="form_element">
        <input type="submit" value="Postita" id="submit">
      </div>
    </fieldset>
  </form>

有多个问题。当用户上传的文件不符合要求（大小，格式等）时，即使$ error！=”，它仍在上传。当用户根本不填写文件输入字段时，如果声明（是的，我知道，我不知道正确的术语...），则代码不应输入文件上传，但是，“上传文件时出错”仍然显示。提交格式不允许的图像时，它仍会上传，但路径类似于/ url / folder / img。-没有文件扩展名。

布赖恩

试试这个 ...

<?php
IF (isset($_POST['submit'])) {

    $err = "";
    $mimetypes = array('image/gif', 'image/jpeg', 'image/pjpeg', 'image/jpg', 'image/png', 'image/x-png'); 
    $imgexts = array('gif', 'jpeg', 'jpg', 'png'); 

    IF (!empty($_FILES['file']['name'])) {

        $img = $_FILES['file']['name'];
        $temp = $_FILES['file']['tmp_name'];
        $ext = strtolower(substr(strrchr($_FILES['file']['name'], '.'), 1));// file ext.
        $info = @getimagesize($_FILES['file']['tmp_name']); 
        $imgw = $info[0]; // width 
        $imgh = $info[1]; // height 
        $mime = image_type_to_mime_type($info[2]);

        IF (!in_array($ext, $imgexts)) { 
            $err .="<li>File type (".$ext.") is not supported. (Only ".implode(", ",$imgexts).")</li>"; // Non-supported file type 
        }ELSE{
            // 
            IF (!in_array($mime, $mimetypes)) { 
                $err .="<li>Mime type (".$mime.") is not supported. (Only ".implode(", ",$mimetypes).")</li>"; // Non-supported mime type 
            }

        }

    }ELSE{ 
        $err ="<li>Select a file to upload (".implode(", ",$imgexts).")</li>";
    }


    IF (!empty($err)) {

        echo '<p>Errors:</p><ul>'.$err.'</ul>';

    }ELSE{

        // good to go

    }

}ELSE{

    // form not sumbitted 


}
?>