Common Functions

CodeIgniter ships global helper functions that cover the tasks you repeat in almost every application. This topic groups the ones you will use most.

URLs

echo base_url('assets/css/app.css');
echo site_url('products');
echo current_url();
echo route_to('product', 42);
echo url_to('Catalog::show', 42);

base_url() resolves assets and uploads. site_url() builds application URLs. route_to() and url_to() generate URLs from named routes or controller actions.

Output and forms

echo esc($title, 'html');
echo old('email');
echo csrf_token();
echo csrf_hash();

esc() prevents cross-site scripting. old() repopulates a form after validation fails. The CSRF functions produce the field name and value used in forms.

Application helpers

$value = env('app.timezone', 'UTC');
$mailer = service('email');
helper('text');
$config = config('App');

Diagnostics

log_message('info', 'Cache warmed for {count} items', ['count' => $count]);
$timer = \Config\Services::timer();
$timer->start('report');

Working with cache

$cache = service('cache');
$cache->save('home_stats', $stats, 300);

Command-line checks

if (is_cli()) {
    echo "Running from the command line\n";
}

These functions live in helpers that CodeIgniter loads for you. If a function is missing in a custom context, load its helper with helper('url') or the relevant helper name.