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Implementation principle of PHP upload and download

GuanhuiOriginal: 2020-05-13 14:26:532490browse

The implementation principle of PHP upload and download

First, the user submits the file to the PHP server, and PHP will automatically temporarily store the file; Then the business code saves the file to the server and returns the file access address; finally, the front end accesses and downloads the file based on the access address.

File upload example

HTML：

<html>
    <head>
        <title>简单文件上传</title>
    </head>
    <body>
        <form action="./upload_file.php" method="POST" enctype="multipart/form-data">
            <label for="file">文件:</label>
            <input type="file" name="myfile" id="file">
            <button type="submit">上传文件</button>
        </form>
    </body>
</html>

PHP：

<?php
header("content-type:text/html;charset=utf-8");
//获取文件配置信息
$myfile = $_FILES["myfile"]["name"];
//临时目录
$tmp = $_FILES[&#39;myfile&#39;][&#39;tmp_name&#39;];
//文件大小
$size = $_FILES[&#39;myfile&#39;][&#39;size&#39;];
//文件类型
$type = $_FILES[&#39;myfile&#39;][&#39;type&#39;];
//文件上传
$error = $_FILES[&#39;myfile&#39;][&#39;error&#39;];

if($_FILES["myfile"]["error"] > 0){
    echo "错误信息".$_FILES["myfile"]["error"];
} else {
    echo $myfile.&#39;<br>&#39;;
    echo $tmp.&#39;<br>&#39;;
    echo $size/1024 .&#39;KB<br>&#39;;
    echo $type.&#39;<br>&#39;;
    echo $error.&#39;<br>&#39;;
}

if(file_exists("./".$_FILES["myfile"]["name"])){
    echo $_FILES["myfile"]["name"] . "   文件存在";
} else {
    move_uploaded_file($_FILES[&#39;myfile&#39;][&#39;tmp_name&#39;],"./". $_FILES["myfile"]["name"]);
    echo "文件位置："."./". $_FILES["myfile"]["name"];
}

Implementation principle of PHP upload and download

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