Simmer is a command line utility to generate scaffolding, migrations, and other boilerplate code for Vapor applications. It uses multiple commands to be able to generate models, controllers, views, protocols, and resources for Vapor backed servers. It follows a strict folder structure for your application, so the ability to generate the contents of the file is allowed without actually writing to your project. Simmer also relies on a few Swift packages for generating responses in controllers and managing migrations:
- AutoMigrator: pulls migrations automatically without explicitly telling the application to load it.
- FormattedResponse: Response handler to switch between formats without needing to define different routes.
The models folder is where the base file for each model lives. This includes the type definitions for the model, the schema name, and initialization code. The default migration is added when a model is created to the migrations folder as opposed to residing in the model itself, keeping resources separate.
Controllers are how the application interacts with clients. By default, both Web and API controllers are generated for simmer. The reasoning is that there are different attributes that may be exposed for an API versus the Web representation, especially with Leaf templates. However, if basic CRUD operations are all that are needed, Scaffold and Model both accept the --basic flag which will generate a single controller for the Model. If --skip-web or --skip-api is passed to scaffold, only the necessary representable and file will be generated.
The migrations folder holds all the migrations for models. They are generated using MTimestamp_MigrationName format, to ensure that all migrations are run in order. If the migration is generated for a model, that models resource folder is updated to include the migration. If the migration is not for a model, the migration is appended to the main routes file. To pass a model to an individual migration file, use --model ModelName or -m ModelName.
To be able to run in your own project without installing through homebrew, you can run swift run build --configuration release and then copy the output into your path.
The folder structure for adding new commands is as follows:
All code starts in the Commands folder. All commands should be named XxxCommand and should have a _commandName of xxx. The commands then call into the FileLoader folder. These use the files in DefaultFiles to find and replace information. Generators can be used to manage data to make the data easily repeatable should it need to be used in another FileLoader. The FileLoader should be the only file to actually write to the Sources folder.