特定文件类型是否允许php上传 [英] Specific file type allowed? php upload

问题描述

我创建了一个图片上传器，我不知道如何做，只有文件类型可以是.jpg，所以我问你，你知道吗？到目前为止：

 <？php 
 session_start（）; 
 if（$ _ SESSION ['username']）{
 $ target_path =users / $ username /; 
 
 $ target_path = $ target_path。 basename（$ _FILES ['uploadedfile'] ['name']）; 
 
 if（move_uploaded_file（$ _ FILES ['uploadedfile'] ['tmp_name']，$ target_path））{
 echoThe file。 basename（$ _FILES ['uploadedfile'] ['name']）。 
已上传; 
 header（Location：user.php）; 
} else {
 echo上传文件时出错，请重试！; 
 
 
 else {
 echo只有会员才可以在这里注册< a href ='index.php'> here< / a>; 
} 
？> 
  

还有一件事，我如何将上传的文件重命名为：profile.jpg？

解决方案

这里有一些重要的事情需要考虑：

所有，从不依赖于提供的文件扩展名。如果需要，我可以上传一个扩展名为 .jpg 的php文件。诚然，我可能不得不做更多的事情来让它在你的服务器上作为一个php文件执行，但它肯定不是一个有效的图像。

如果上传成功， $ _ FILES ['uploadedfile'] ['type'] 将保存请求提供的MIME类型。然而，这也不应该被信任，因为这也可能被篡改。

一种更可靠的方法来确定上传的文件是否实际上是一个类型为jpeg的图像是使用函数 getimagesize 。 getimagesize（）如果它不是一个有效的图像，将返回false，并返回一个包含图像信息的数组，如果它将该文件识别为图像。数组的索引 2 将保存一个与其中一个常量，以 IMAGETYPE _ 开始。

  $ info = getimagesize（$ _FILES ['uploadedfile'] ['tmp_name']）; 
 if（$ info！== false）
 {
 //文件是一个以
 
开头的图像if（$ info [2] == IMAGETYPE_JPEG） 
 {
 //文件看起来是一张有效的jpeg图片
} 
} 
  

据我所知，这是一种老派的方法，尽管它是可靠的。我相信，依赖于平台Windows / * nix）和版本（< 5.3，> = 5.3），但有更可靠的方法来确定文件的实际MIME类型。

编辑：

我忘记了关于
$ b

target_path。 basename（$ _FILES ['uploadedfile'] ['name']）;

... with this：

  $ target_path = $ target_path。 profile.jpg; 
  

换句话说，当您使用 move_uploaded_file（） code>第二个参数将是新路径（包括新文件名）。


Im creating a image uploader, and i dont know how to do so only the filetype can be .jpg so im asking you, do you know it?

heres what i got so far:

    <?php
session_start();
if($_SESSION['username']) {
    $target_path = "users/$username/";

    $target_path = $target_path . basename( $_FILES['uploadedfile']['name']); 

    if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
        echo "The file ".  basename( $_FILES['uploadedfile']['name']). 
        "has been uploaded";
        header("Location: user.php");
    } else{
        echo "There was an error uploading the file, please try again!";
    }
}
    else {
            echo "Only members can be here. Register <a href='index.php'>here</a>";
  }
  ?>

And one more thing, how may i rename the uploaded file to : "profile.jpg" ?

解决方案

There are some important things to consider here:

First of all, never rely on the file extension that was provided. I could upload a php file with the extension .jpg if I wanted. Granted, I'd probably have to do some more to actually get it to execute as a php file on your server, but it certainly was not a valid image.

If the upload was successful, $_FILES[ 'uploadedfile' ][ 'type' ] will hold the mime-type that was provided by the request. However, this should also not be trusted, as this can be tampered with as well.

A more reliable way to determine whether the uploaded file is actually an image of type jpeg is to use the function getimagesize. getimagesize() will return false if it's not a valid image and will return an array with information about the image, if it recognized the file as an image. Index 2 of the array will hold a value that corresponds with one of these constants that begin with IMAGETYPE_.

$info = getimagesize( $_FILES[ 'uploadedfile' ]['tmp_name'] );
if( $info !== false )
{
    // file is an image to begin with

    if( $info[ 2 ] == IMAGETYPE_JPEG )
    {
        // file appears to be a valid jpeg image
    }
}

This is somewhat of an old school method which, as far as I know, is reliable though.

I believe, depending on platform (Windows/*nix) and version (< 5.3, >= 5.3) there are more reliable ways to determine the actual mime-type of a file though. I'll see what I can find for you about that later on.

edit:
I forgot about the renaming part.

Simply replace this:

$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);

... with this:

$target_path = $target_path . 'profile.jpg';

In other words, when you move the file with move_uploaded_file() the second argument will be the new path (including the new file name).

这篇关于特定文件类型是否允许php上传的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！