Modules#

Silverstripe CMS is designed to be a modular application system - even the CMS is simply a module that plugs into the core framework.

A module is a collection of classes, templates, and other resources that is loaded into a directory. Modules are Composer packages, and are placed in the vendor/ folder. These packages need to contain one of the following in its root directory to be recognised as a module by Silverstripe CMS:

• a _config directory
• a _config.php file
• a composer.json file with a type of either silverstripe-vendormodule or silverstripe-theme(example).

Like with any Composer package, we recommend declaring your PHP classes through PSR-4 autoloading. Silverstripe CMS will automatically discover templates and configuration settings within your module when you next flush your cache.

Finding modules#

• Packagist.org "Silverstripe" tag
• GitHub.com "Silverstripe" search

Installation#

Modules are installed through the Composer package manager. It enables you to install modules from specific versions, checking for compatibilities between modules and even allowing to track development branches of them. To install modules using this method, you will first need to setup Silverstripe CMS with Composer.

Each module has a unique identifier, consisting of a vendor prefix and name. For example, the "linkfield" module has the identifier silverstripe/linkfield as it is published by Silverstripe. To install, use the following command executed in the project root folder:

composer require silverstripe/linkfield

This will fetch the latest compatible stable version of the module.

Composer uses version constraints. You can declare a specific constraint to install if you want to, but typically if you leave the constraint blank Composer will correctly detect an appropriate constraint for you based on your project's stability configuration.

To lock down to a specific version, branch or commit, read up on "lock" files.

Creating a module#

Creating a module is a good way to re-use code and templates across multiple projects, or share your code with the community. Silverstripe CMS already has certain modules included, for example the cms module and various functionality such as commenting and spam protection are also abstracted into modules allowing developers the freedom to choose what they want.

Create a new repository#

The easiest way to get started is our Module Skeleton.

You can create a new repository based on the skeleton using the "Use this template" function on GitHub.

Allow your module to be importable by Composer#

You could import your project using Composer right away - but the name in your composer.json file is still "silverstripe-module/skeleton" instead of being the appropriate name for your module.

You can either edit the file directly in GitHub, or you can clone the repository to a temporary directory - but bare in mind you'll only be using this directory to update the composer.json file. Once that's updated in the repository, you'll use Composer to include your module in a Silverstripe CMS project and do your development from there.

Here is an example for a module that builds on the functionality provided by the silverstripe/linkfield module, so it has that module as a dependency:

{
    "name": "my_vendor/module_name",
    "description": "Short module description",
    "type": "silverstripe-vendormodule",
    "require": {
        "silverstripe/framework": "^6.0",
        "silverstripe/cms": "^6.0",
        "silverstripe/linkfield": "^5.0"
    }
}

Commit your change, and if you chose to make this change locally on your computer, push the changes back up to GitHub. You can delete the temporary directory now, if you created one.

Add the module to a project for development#

To develop the module, you'll want to include it in a Silverstripe CMS project. It's up to you whether you do this in a project you already have set up, or start a new one from scratch specifically for this purpose. In most cases we recommended using a new project, at least at first.

If this is a module you intend to be available publicly, it might make sense to submit the repository to Packagist at this stage.

Once you've done that, you can simply install it like you would any other dependency - just make sure you use the --prefer-source option, which will ensure Composer installs the module directly from GitHub and keeps the initialised local git repository.

composer require my_vendor/module_name:dev-main --prefer-source

Once Composer has installed the module, you can develop your module in the vendor/my_vendor/module_name directory, and commit/push changes from there to the remote repository in GitHub.

Including a private module in your project#

Including public or private repositories that are not indexed on Packagist is different from simply using the composer require command. We will need to point Composer to specific URLs. Background information can be found at Working with project forks and unreleased modules.

For our example module you can add the following lines to your composer.json file in the root directory of your main project.

{
    "repositories": [
        {
            "type": "vcs",
            "url": "git@github.com:my_vendor/module_name.git",
        }
    ]
}

This will add the repository to the list of URLs Composer checks when updating the project dependencies. You can now include the dependency as normal, e.g:

composer require my_vendor/module_name:dev-main --prefer-source

Open-sourcing your creation for the community to use#

In case you want to share your creation with the community, read more about publishing a module.

Module standard#

The Silverstripe CMS module standard defines a set of conventions that high-quality Silverstripe CMS modules should follow. It’s a bit like PSR for Silverstripe CMS. Suggested improvements can be raised as pull requests. This standard is also part of the more highlevel Supported Modules Definition which the Silverstripe CMS project applies to the modules it creates and maintains directly.

Coding guidelines#

• Complies to a well defined module directory structure and coding standards:

  • templates/ (for templates e.g. *.ss files)
  • src/ (for .php files)
  • tests/ (for *Test.php test files), and;
  • _config/ (for .yml config files)
• The module is a Composer package.
• All Composer dependencies are bound to a single major release (e.g. ^6.0 not >=6) unless there are obvious reasons not to for some specific dependency.
• There is a level of test coverage.
• Uses strong typing where appropriate.

• A clear public API documented in the docblock tags.

  • If parameters and return values don't need additional description and are strongly typed, these should be ommitted from the docblock.
• Code follows PSR-1 and PSR-2 style guidelines.
• .gitattributes will be used to exclude non-essential files from the distribution. At a minimum tests, docs, and IDE/dev-tool config should be excluded.
• Add a PSR-4 compatible autoload reference for your module.

Documentation guidelines#

Documentation will use the following format:

• README.md provides:

  • Links or badges to CI and code quality tools.
  • A short summary of the module, end-user.
  • Installation instructions.
• CONTRIBUTING.md explaining terms of contribution.
• Has a licence (LICENSE file) - for Silverstripe CMS supported this needs to be BSD.

• Detailed documentation in /docs/en as a nested set of GitHub-compatible Markdown files.

  • It is suggested to use a documentation page named userguide.md in docs/en/ that includes documentation of module features that have CMS user functionality (if applicable). For modules with large userguides, this should be in a directory named userguide with an index.md linking to any other userguide pages.
• Links and image references are relative, and are able to be followed in viewers such as GitHub.
• Markdown may include non-visible comments or meta-data.

Documentation will cover:

• Installation
• Configuration
• Usage guides for key features; screenshots are recommended.

Related#

• Module Skeleton
• Publishing a module