How to query the maximum size of uploaded files in php

How to query the maximum size of uploaded files in php: 1. Check the "php.ini" configuration file and query the maximum size of uploaded files by looking for the "post_max_size" and "upload_max_filesize" options; 2. Use "ini_get() " function to get the value of the option in the "php.ini" file.

Operating system for this tutorial: Windows 10 system, PHP version 8.1, Dell G3 computer.

How to query the maximum value of uploaded files in php

1. First, we need to check the php.ini configuration file. This file is usually located in the root directory of the server. After opening this file, we need to look for the two options post_max_size and upload_max_filesize. The post_max_size option specifies the maximum data size that can be submitted by POST, including uploaded files and other data in the form. The upload_max_filesize option specifies the maximum size of a single uploaded file. These two together specify the maximum size of the uploaded file.

2. In the php.ini file, we can query the maximum size of file upload by looking for the post_max_size and upload_max_filesize options. Both options have a default value. If these two options are not set, the default value is 2M. We can modify the values ​​of these two options to change the maximum size of uploaded files. For example, if we set the value of the upload_max_filesize option to 10M, the maximum size of the uploaded file will increase to 10M.

3. In addition to querying the maximum size of uploaded files by viewing the php.ini file, we can also use PHP code to query the maximum size of uploaded files. The following is a PHP code example:

<?php
  echo ini_get(&#39;post_max_size&#39;).&#39;<br>&#39;; //将打印出post_max_size的值
  echo ini_get(&#39;upload_max_filesize&#39;).&#39;<br>&#39;; //将打印出upload_max_filesize的值
?>

The ini_get() function in the code is used to get the value of the option in the php.ini file. Using this function, we can query the maximum size of the uploaded file and display it on the web page.

The meaning of ini_get

ini_get is to obtain the value of the environment variable in php.ini.

1. Syntax introduction

string ini_get (string varname)

If the return value is Boolean, it is 0 or 1

Example:

/*
我们的 php.ini 包含了以下的设置：
display_errors = On
register_globals = Off
post_max_size = 8M
*/
<?php
echo &#39;display_errors = &#39; . ini_get(&#39;display_errors&#39;) . "\n";
echo &#39;register_globals = &#39; . ini_get(&#39;register_globals&#39;) . "\n";
echo &#39;post_max_size = &#39; . ini_get(&#39;post_max_size&#39;) . "\n";
echo &#39;post_max_size+1 = &#39; . (ini_get(&#39;post_max_size&#39;)+1) . "\n";
echo &#39;post_max_size in bytes = &#39; . return_bytes(ini_get(&#39;post_max_size&#39;));
?>

If we want to get the variable value in the entire php.ini, we can use the enhanced function ini_getini_get_all()；

ini_get_all()The function returns the entire php environment variables in the form of an array;

The usage is also very simple, for example

<?php
$ini = ini_get_all();
print_r($ini);
?>

Of course, if you just want to see php It is more convenient to use phpinfo() for configuration information.

ini_set has the function of changing php.ini settings. This function receives two parameters: the name of the configuration variable that needs to be adjusted, and the new value of the variable.

For example, to increase the maximum execution time when a script appears:

<?php
ini_set(&#39;max_execution_time&#39;, 600)
// more code
?>

Such a setting will only affect the script being set. Once the script has finished executing, the variable will automatically be restored to its original value.

php framework

1. Laravel, Laravel is a free and open source PHP application framework.

2. Phalcon, Phalcon is the fastest running PHP framework.

3. Symfony, Symfony is a PHP framework prepared for Web projects.

4. Yii, Yii is a fast, safe and professional PHP framework.

5. CodeIgniter, CodeIgniter is a very agile open source PHP framework.

6. CakePHP, CakePHP is an old PHP framework.

7. Kohana, Kohana is an agile but powerful PHP framework.

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