Introduction

    In previous versions of UserFrosting, you had to directly modify the files that come with the default installation in order to add your own functionality. For example, if you wanted to add a field to the user registration page, you had to actually modify register.twig. Or, if you wanted to add a new relation on the User class, you had to modify the actual User.php class that comes with UserFrosting.

    Starting in version 4, this is no longer the case! UserFrosting 4 now introduces the Sprinkle system as a way to completely isolate the code and content that you and your team produce from the core UserFrosting installation, as well as third-party code.

    What is a "Sprinkle"?

    A Sprinkle is a functionally cohesive unit of code and content that fits neatly into its own separate directory. A Sprinkle could implement a core component, a third-party plugin or theme, or even an entire website! In fact, the first step in building your application with UserFrosting is to create a new sprinkle.

    Each Sprinkle can contain any or all of the following entities:

    • assets (JS, CSS, images, etc)
    • configuration files
    • translations (i18n)
    • route endpoints (URL definitions)
    • validation schema
    • PHP code (typically classes)
    • templates (Twig files)
    • installation scripts (migrations)

    Sprinkles are loaded in a specific order, and entities of each type in one sprinkle can extend entities of the same type in other sprinkles. We'll explain exactly what we mean by "extend" in a minute.

    Each Sprinkle is located in its own subdirectory under the main app/sprinkles/ directory. To create a new Sprinkle, simply create a new subdirectory in app/sprinkles/.

    Loading Sprinkles

    Sprinkles are automatically loaded via the sprinkles.json file in your app/sprinkles/ directory. During the installation process, we had you create a basic sprinkles.json file:

    {
        "base": [
            "account",
            "admin"
        ]
    }

    The base key contains an array of Sprinkles that UserFrosting will load after it loads the core Sprinkle (The core Sprinkle is automatically loaded for every project). To have UserFrosting load another Sprinkle, simply add it to this array. For example, if you have a site Sprinkle:

    {
        "base": [
            "account",
            "admin",
            "site"
        ]
    }

    By default, the UserFrosting repository is set to ignore the sprinkles.json file. You may wish to commit this to your own personal repository, though. In this case, simply remove it from your .gitignore file.

    The order in which we load our Sprinkles is important. Files in one Sprinkle may override files with the same name and path in previously loaded Sprinkles. For example, if we created site/templates/pages/about.html.twig, this would override core/templates/pages/about.html.twig because we load the site Sprinkle after the core Sprinkle.

    Default Sprinkles

    A basic UserFrosting installation comes with four sprinkles, each of which can be found in its own subdirectory in /app/sprinkles:

    app
    ├──sprinkles
       ├── account
       ├── admin
       ├── core
       └── root

    Of these, 3 comprise the bulk of UserFrosting's functionality: core, account, and admin.

    Core

    core contains most of the "heavy lifting" PHP code, and is required for every project. For example, it loads most of UserFrosting's Composer requirements, and contains classes for features like mail, request throttling, and the code that actually manages the Sprinkle system itself!

    Account

    The account sprinkle handles user modeling and authentication, user groups, roles, and access control, and contains the routes, templates, and controllers needed to implement pages for registration, password reset, login, and more.

    Admin

    The admin sprinkle contains the routes, templates, and controllers to implement the administrative user and group management interface, as well as the site settings and role and permission management interfaces.

    root is a special theme Sprinkle, used to provide some cosmetic styling for the root user account.

    Now that we're familiar with the basic concept, let's dig into the contents of a Sprinkle!