Implementation principle of PHP upload and download

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：

    
        
    

    
        

            文件:
            
            上传文件
        
    

PHP：

 0){
    echo "错误信息".$_FILES["myfile"]["error"];
} else {
    echo $myfile.'
';
    echo $tmp.'
';
    echo $size/1024 .'KB
';
    echo $type.'
';
    echo $error.'
';
}

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

Recommended tutorial:《PHP Tutorial》

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