In-depth analysis of php upload files

This article mainly shares with you the in-depth analysis of PHP upload files. We have also shared many articles about PHP upload files with you before. I hope this article can help everyone.

1.phpUpload file configurationphp.iniConfiguration:

(1)file_uploads=on|off ： Determine PHP on the server Whether the script can accept file uploads.

（2）max_execution_time=integer ： PHP The maximum amount of time, in seconds, that a script can execute before registering a fatal error

.

（3）memory_limit=integer ： Settings The maximum memory that a script can allocate, in MB. This prevents runaway scripts from monopolizing server memory.

（

4

）upload_max_filesize=integer : Set the maximum size of the uploaded file to MB is the unit. This directive must be smaller than

post_max_size

. （

5

）upload_tmp_dir=string ： Settings Uploaded files must be stored in a temporary location on the server before being processed, until the file is moved to its final destination.

（

6

）post_max_size=integer : OK to pass POSTThe maximum size of the message that the method can accept, in MB as the unit

2.php

Upload related methods

（1）bool is_uploaded_file(string $filename)

Definition: is_uploaded_file() The function determines whether the specified file is uploaded through HTTP POST

Parameters $filename : $_FILES['file_img']['tmp_name'](Example)

Specifies the file to be checked: C:\Windows\Temp\php9632.tmp

(2)bool move_uploaded_file ( string $filename , string $destination )

Definition: move_uploaded_file () Function moves the uploaded file to a new location General and is_uploaded+_file()Method used together

Parameters $filename: $_FILES['file_img']['tmp_name'](example)

Specify the files to be moved : C:\Windows\Temp\php9632.tmp                                                                             ## $ DESTION

##:

DIRNAME (__file __). Ds.'uploads'.ds. $ _ Files ['file_img'] ['name'] (Example) Specify the location of the file to be moved:

D:\myWAP\myWeb \learn\php_upload\uploads\hm_g_img.jpg##3.phpUpload case: It is stipulated that only image files can be uploaded

##（

1
）

Necessary folder and file

（2）file_unload_select.php file is used for the HTMLBrowse selection, upload click:

##enctype = "multipart/form-data" Fixed Writing method, otherwise the file upload will fail

action = "url"

## method="post"

Generally upload is post

##（

3）upload.php File is used to process uploaded files Determine the type of uploaded file and Move the file to the specified directory on the server:

//接收上传文件
print_r($_FILES);
define('DS',DIRECTORY_SEPARATOR);


//判断当前上传的文件是否为图片
$img_type_arr = array('image/png','image/jpeg','image/jpeg');

//for循环遍历数组 -- 第一方法判断是否为数组中的子项
for($i=0;$i<count($img_type_arr);$i++)
{
       if($img_type_arr[$i] != $_FILES[&#39;file_img&#39;][&#39;type&#39;] && ($i == count($img_type_arr)-1) )
       {
                echo ""
                exit;
       }
}



//数组方法array_in() -- 第二方法判断是否为数组中的子项
if(!is_uploaded_file($_FILES[&#39;file_img&#39;][&#39;tmp_name&#39;]))
{
      //如果临时文件不存在,则说明没有上传到临时文件夹
      echo  &#39;上传到临时文件夹失败&#39;;
}
else
{

   //echo &#39;上传到临时文件夹成功&#39;;
   $img_path = dirname(__FILE__).DS.&#39;uploads&#39;.DS.$_FILES[&#39;file_img&#39;][&#39;name&#39;];

   //echo $img_path;

   //进行移动文件到服务器地址
   if(@move_uploaded_file($_FILES[&#39;file_img&#39;][&#39;tmp_name&#39;],$img_path))
   {
        //显示图片
        echo "<img src=".$img_path." />"
   }
   else
   {
        cho &#39;移动文件失败&#39;;

   }
}

（

4）show_image.php Used to receive the image file path and display the successfully uploaded image:

$img_path = $_GET['url'];

echo "";

(

5) The core of uploading is to use $_FILES sub-parameters, complete uploading and judgment :

Array ( [file_img] => Array ( [name] => news_001_01.jpg [type] => image/jpeg 
[tmp_name] => C:\Windows\Temp\php504D.tmp [error] => 0 [size] => 158360 ) )

Analysis:

$_FILES['file_img']['name'] : news_001_01.jpg

Upload file name$_FILES['file_img'][ 'type'] : image/jpeg

Type of uploaded file$_FILES['file_img'][' tmp_name '] : C:\Windows\Temp\ php504D.tmp

The storage path of the temporary file of the uploaded file$_FILES['file_img']['error '] : 0 , 1, 2, 3, 4

0 -& GT; ## Represents the file upload successfully

1 -& GT; The size of the file exceeds the agreed value (specified by PHP.ini) 2 ->

Indicates uploading the file The size exceeds the agreed value (HTMLspecified in the form) 3 ->

Indicates that the file is only partially Upload## 4 ->

means no files were uploaded

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