如何在PHP中检查上传的文件类型

问题描述

我用这段代码来检查图像的类型，

I used this code to check for the type of images,

$f_type=$_FILES['fupload']['type'];

if ($f_type== "image/gif" OR $f_type== "image/png" OR $f_type== "image/jpeg" OR $f_type== "image/JPEG" OR $f_type== "image/PNG" OR $f_type== "image/GIF")
{
    $error=False;
}
else
{
    $error=True;
}

但有些用户抱怨他们在上传任何类型的图像时出错，而有些用户则没有出错！

but some users complain they get an error while uploading any type of images, while some others don't get any errors!

我想知道这是否能解决问题:

I was wondering if this fixes the problem:

if (mime_content_type($_FILES['fupload']['type']) == "image/gif"){...

有什么意见吗?

推荐答案

永远不要使用 $_FILES..['type'].其中包含的信息根本没有经过验证，它是用户定义的值.自己测试类型.对于图片，exif_imagetype 通常是一个不错的选择选择:

Never use $_FILES..['type']. The information contained in it is not verified at all, it's a user-defined value. Test the type yourself. For images, exif_imagetype is usually a good choice:

$allowedTypes = array(IMAGETYPE_PNG, IMAGETYPE_JPEG, IMAGETYPE_GIF);
$detectedType = exif_imagetype($_FILES['fupload']['tmp_name']);
$error = !in_array($detectedType, $allowedTypes);

或者，finfo 函数 也很棒，如果您的服务器支持它们.

Alternatively, the finfo functions are great, if your server supports them.

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