PHP

Error warnings for PHP are helpful during development, where you can use them for debugging. Showing the same errors and warnings in a production environment could pose a security …
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PHP allows specific functions to be disabled to avoid misuse and for security reasons. It is used to harden a PHP deployment, especially in a shared hosting environment.

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The max_execution_time directive defines the maximum execution time for your PHP scripts and applications. If not configured, the default maximum execution time for a PHP script is 30 seconds. …
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Some PHP functions could be a security risk if allowed in a system. These functions include exec(), which could be used to execute shell commands in a system if …
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PHP scripts are only allocated a certain amount of memory that it can use, and whet it reaches the limit, it will produce the following error;

PHP Fatal error: Allowed memory size of xxxx bytes exhausted (tried to allocate yyyy) in yourscript.php

To fix this, you’ll need to increase the memory limit for PHP scripts using any of the following methods;

Maximum upload file size for PHP is bound to the lowest value of both post_max_size and upload_max_filesize directives in your configuration. post_max_size affects maximum file upload size as file upload is normally an HTTP POST operation.

You can update your PHP configuration file for these two directives to the values that fit your requirement and then restart your web server.

The following example allows for file upload of not more than 200MB.

post_max_size = 200M
upload_max_filesize = 250M

Alternatively, you can add the following lines in your .htaccess and the setting will apply to scripts from within the .htaccess‘ directory.

php_value upload_max_filesize 200M
php_value post_max_size 250M

Restart Apache for the changes to take effect.

Here are some ways that you can check the installed version of PHP in your system;

1. Run php -v from the command line.

   $ php -v
   PHP 7.0.19 (cli) (built: Jun 21 2017 07:13:57) ( NTS )
   Copyright (c) 1997-2017 The PHP Group
   Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies

2. Run php -i from the command line.

   $ php -i | grep "PHP Version"
   PHP Version => 7.0.19
   PHP Version => 7.0.19

3. Print PHP_VERSION_ID from PHP script.

   <?php 
   echo PHP_VERSION_ID;
   //Sample output: 70019
   ?>

4. Print phpversion() output from PHP script.

   <?php 
   echo phpversion();
   //Sample output: 7.0.19
   ?>

5. View from phpinfo() output

   <?php 
   phpinfo();
   ?>

   

6. Query your package manager where the PHP packages are installed from. Here’s a list of some common package managers and the corresponding commands;

You could get the following warning if timezone is not configured for PHP when using date related function such as date() or date_default_timezone_get().

You can configure timezone for PHP by setting up date.timezone in your configuration file to any of the supported timezones. You can view the list of supported timezones from PHP‘s official documentation.

The following example sets the timezone to America/Los_Angeles

[Date]
; Defines the default timezone used by the date functions
; http://php.net/date.timezone
date.timezone = America/Los_Angeles

If you’re using PHP 5.1.0 or later, you can you can independently set the timezone for each of your PHP script by calling the date_default_timezone_set function with the timezone as the parameter.

bool date_default_timezone_set ( string $timezone_identifier )

The example below sets the timezone for the rest of the script to America/Los_Angeles.

<?php
date_default_timezone_set('America/Los_Angeles');
?>

Don’t forget to restart your webserver after changing the PHO configuration file for the changes to take effect.

PHP will exit with the following error once it reaches the maximum allowed time for it to execute your scripts;

Fatal error: Maximum execution time of 30 seconds exceeded in yourscript.php

You can avoid this error by increasing the maximum execution time for PHP. This can be set globally or from within your PHP scripts from these options;

PHP‘s configuration file location might differ from one platform to another. Here’s an incomplete list of the possible location for PHP‘s configuration file;

If you’re on a Unix based operating system, you can run php -i from the terminal and look for Loaded Configuration File from the output to get the location for your exact system such as the following;

$ php -i | grep 'Loaded Configuration File'
Loaded Configuration File => /etc/php.ini