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Functional Mode

Functional Mode, as we call it is just a fancy name given to a bunch of predefined functions in your leaf app which allow you to create your entire app or API without relying on classes with lengthy initializers and namespaces. With functional mode, everything is handled for you under the hood and is given to you in one global function.

Functional mode is 100% optional as seen in the examples in the introduction section. It also requires zero setup or configuration since it's available right after installing Leaf.


require __DIR__ . '/vendor/autoload.php';

app()->get('/', function () {
  response()->json(['message' => 'Leaf is amazing!']);


How to configure leaf

Since leaf provides extra options which can be passed into leaf on init, how do you configure the leaf object if you have no direct access to it?

  • Use the config method

There is a configuration method on leaf which allows you to set extra configurations if needed. You might never have to use this, but depending on the complexities to tackle, you might want Leaf to behave a certain way. You can call the config method on app() to set these application config.


require __DIR__ . '/vendor/autoload.php';

app()->config('app.down', true);

app()->get('/', function () {
  response()->json(['name' => 'Leaf']);

  • Use the config class

Besides this, you can use the Leaf\Config class to pass in configuration options


require __DIR__ . '/vendor/autoload.php';

Leaf\Config::set('app.down', true);

app()->get('/', function () {
  response()->json(['name' => 'Leaf']);


The main difference here is that the second method sets the config before the Leaf app is initialized. This means that during initialization, Leaf will use the config that has been set, however, for the first method, the config is loaded only after Leaf is initialized and thus, not used in the initialization process.


This function returns the current instance of the Leaf application. If none exists, it creates and returns it.


$app = new Leaf\App;

$app->get("/", function () {
  app()->response()->json(["name" => "Leaf"]);

app() on line 4 will return the leaf instance $app defined on line 1. If however, no leaf instance is found, app() will create a new instance and return it.



require __DIR__ . "/vendor/autoload.php";

app()->get("/", function () {
  response()->json(["name" => "Leaf"]);


As seen on line 5, no app instance already exists and so one is created and returned. This gives you powerful tooling and lets you get rid of imports, namespaces...


In other frameworks like laravel which also ship an app method, calling app will return the laravel instance, not leaf's. In such situations, you can use the app instance config


This global function allows you to get environment variables set in your .env file. _env takes in 2 parameters:

  • The name of the env variable to get (required)
  • The default value of the env variable to get if it doesn't exist (optional)
// get value
$mode = _env("APP_MODE");

// get value with default
$mode = _env("APP_MODE", "production");


These are the globals provided by default with Leaf, however, some Leaf modules come in with their own globals, for instance, leafs/session has the session and flash globals. All globals are named carefully to avoid conflicts with other popular PHP packages.


Leaf and it's modules only set a global if a function with that name doesn't exist. This is to avoid unintentionally overwriting important functions in your code.

If you run into a challenge like this, you can rename your functions if you defined them yourself.


Modules which extend functional mode will have a section on their documentation with a functional mode tag. You can always look out for that


request is a global function which returns the leaf request object. The request global is provided from the leaf http module which comes with leaf 3 out of the box, so there's no need to install it.

$username = request()->get('username');


This global returns the leaf response object. The response global is provided from the leaf http module so there's no need to install it since it comes with leaf 3 out of the box.


This global allows you to set/get a cookie or return the leaf cookie object. The cookie global is provided from the leaf cookie module.

// set multiple cookies
cookie(["name" => "Mychi", "code" => "PHP"]);

// set single cookie
cookie("name", "Mychi");

// get cookie

If nothing is passed into cookie, it returns the leaf cookie object.

cookie()->set("name", "Mychi");


Leaf CSRF provides 2 globals which make working with the package a whole lot easier. To get started you will need to install the leaf csrf module.


This method returns a generated CSRF token.

$token = _token();


This method generates a CSRF field in a form for you.

  <?php _csrfField(); ?>

Leaf Form

Leaf form also provides a form method which returns the entire leaf form object.


You will however need to install the leaf form module to get started.

Leaf Db

After installing the leaf db module, you'll have access to the db global. This function returns an active instance of the database class.

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