如何使上传的文件具有随机名称？答案

【问题标题】：How do I make the uploaded file have a random name?如何使上传的文件具有随机名称？
【发布时间】：2016-10-22 17:02:15
【问题描述】：

我想知道如何让我上传的图片有一个随机名称。使用它，我可以得到一个随机字符串：

    <?php
    function generateRandomString($length = 10) {
return substr(str_shuffle(str_repeat($x='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil($length/strlen($x)) )),1,$length);
    }

    echo  generateRandomString();  // OR: generateRandomString(24)

我用这个来上传它：

$target_dir = "uploads/";
$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);
$uploadOk = 1;
$imageFileType = pathinfo($target_file,PATHINFO_EXTENSION);
// Check if image file is a actual image or fake image
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
    if($check !== false) {
        $uploadOk = 1;
    } else {
        echo "File is not an image.";
        $uploadOk = 0;
    }
}
// Check if file already exists
if (file_exists($target_file)) {
    echo "Sorry, file already exists.";
    $uploadOk = 0;
}
// Check file size
if ($_FILES["fileToUpload"]["size"] > 500000) {
    echo "Sorry, your file is too large.";
    $uploadOk = 0;
}
// Allow certain file formats
if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg" && $imageFileType != "gif" && $imageFileType != "bmp" ) {
    echo "Sorry, only JPG, JPEG, PNG, BMP & GIF files are allowed.";
    $uploadOk = 0;
}
// Check if $uploadOk is set to 0 by an error
if ($uploadOk == 0) {
    echo "Sorry, your file was not uploaded.";
// if everything is ok, try to upload file
} else {
    if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
        echo '<br>The file <img src="http://upimg.comxa.com/uploads/'. basename( $_FILES["fileToUpload"]["name"]). '"> has been uploaded.';
        echo '<br>Direct URL: http://upimg.comxa.com/uploads/'. basename( $_FILES["fileToUpload"]["name"]);
    } else {
        echo "Sorry, there was an error uploading your file.";
    }
}
?>

问题是我不知道怎么做。我从 w3schools 复制了代码，所以我完全不知道它是如何工作的。谢谢。

【问题讨论】：

生成一些UUID，有很多解决办法。

标签： php image upload

【解决方案1】：

如果您使用您的函数更改变量 $target_file，因为这是保存文件的位置。

所以不是在第 2 行：

$target_file = $target_dir . basename($_FILES["fileToUpload"]["name"]);

用这个替换它：

$target_file = $target_dir . generateRandomString();

【讨论】：

这不起作用，它说它已上传但是当我查看 uploads/ 目录时，它不存在。
这可能是因为我忘记了现在没有添加文件扩展名。

【解决方案2】：

通过数组变量获取每个字符

<?php

function rndStr(){
$characters = array("A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","Z","Y","Z");

//generate 6 characters from it 
$charI = rand(0,25);
$charII = rand(0,25);
$charIII = rand(0,25);
$charIV = rand(0,25);
$charV = rand(0,25);
$charVI = rand(0,25);

//output as string
$rnd_name = $characters[$charI].$characters[$charII].$characters[$charIII].$characters[$charIV].$characters[$charV].$characters[$charVI] ; 
return $rnd_name;
}

用法

$target_file = $target_dir . rndStr();

【讨论】：