PHP Specific Constructs

Traversing Arrays

Use the foreach ($array as $name => $value) syntax instead of while (list($name, $value) = each($array)) syntax when traversing arrays. The former has been demonstrated to be more efficient and does not increment the internal pointer of the array. The foreach construct will error if the array is empty or is not an array, so you must check this first.

if ((is_array($array)) && (sizeof($array) > 0)) {
    foreach ($array as $name => $value) {
        // code
    }
}

It should be noted that with PHP 7.2 use of list() = each() syntax will result in warnings and/or errors. It should also be noted that 7.2 also introduced the need for the variable to implement ICountable which are arrays and objects. You should therefore check if variable !=== false before using sizeof() or count()

Error Return Values

When an a function needs to return a generic error, it is best to return boolean false in PHP. This makes it very straightforward to check for.

if (file_list() === false) {
    // there was an error
}

Regular Expressions Are Slow

Only use PHP's regular expression parsing functions (preg_match, preg_replace, preg_quote, etc) when absolutely needed. Often simpler functions such as strstr(), str_replace(), substr(), and explode() can be used, and are much faster.

$items = explode(':', $string));

It's much quicker than:

$items = split(':', $string));

Use preg Functions Instead of ereg

The POSIX based regular expressions in PHP tend to be slower than their Perl-based equivalents. Use Perl-based regular expression functions unless there is an explicit reason to do otherwise.

NOTE: Do not use any deprecated functions: eregi_replace, ereg, or eregi

Quotes

Single quotes are used instead of double where possible. Per string, it doesn't really make a huge difference, but when you have thousands upon thousands of them, every little bit helps.

include_once('./lib/api_tree.php');

However, there isn't any difference between

"This is a $test"

and

'This is a ' . $test

Don't bother trying to break out variables out of the string if you are just going to have to concatenate them.

Including other PHP files

When including other PHP files, you should use the $config['base_path'] to ensure that the base path is configured properly.

If the main file is a web-based page, it should include include/auth.php to ensure that the current user is authenticated.

If the main file is a CLI-based program to be run by end users, it should include lib/cli_check.php and support -h and -v parameters which run display_help() and display_version() respectively.

include($config['base_path'] . '/lib/database.php');

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