(Taylor Swift on Rails. "Mean" Performance)

Swifton

A Ruby on Rails inspired Web Framework for Swift that runs on Linux and OS X.

Getting Started

• Install Development snapshot version from Swift.org or via swiftenv. If you are on OSX I highly recommend swiftenv - latest Swift will be able to coexist with system wide Swift that comes with Xcode.
• swift --version should show something like: Swift version 3.0-dev ...
• Checkout TodoApp example project.
• Run swift build inside app (most of dependencies throw deprecation warnings).
• Run ./.build/debug/Swifton-TodoApp.
• Open http://0.0.0.0:8000/todos in your browser.

Contributing

Contributions are more than welcome! The easiest way to start contributing to Swifton:

• Setup TodoApp
• Pick one issue from the issues list or propose enhancement.
• You can find Swifton source code in Swifton-TodoApp/Packages/Swifton-<version> directory. Packages inside Packages directory comes with Git repository so feel free to do you changes there.
• Compile and test TodoApp, this will help to check your changes and avoid regressions.
• Write tests and run it swift build && swift test (run rm -r Packages/*/Tests inside Swifton folder if tests crashes)
• Commit and push your changes, open pull request.
• Enjoy ;)

Routing

Swifton comes with ready to use Router, also you can use any router as long as it accepts Request and returns Response. Routes are defined in main.swift file. Configured Router is passed to S4 interface supporting server. Router allows to define resources and regular routes.

...
let router = Router.create { route in
  route.resources("todos", controller: TodosController())
}
...

Which is equivalent to:

let router = Router()
router.get("/todos/new", TodosController()["new"])
router.get("/todos/{id}", TodosController()["show"])
router.get("/todos/{id}/edit", TodosController()["edit"])
router.get("/todos", TodosController()["index"])
router.post("/todos", TodosController()["create"])
router.delete("/todos/{id}", TodosController()["destroy"])
router.patch("/todos/{id}", TodosController()["update"])

Configured routes then are passed to application server.

...
serve { request in
    router.respond(request) 
}
...

Controllers

A controller inherits from ApplicationController class, which inherits from Controller class. Action is a closure that accepts Request object and returns Response object.

class TodosController: ApplicationController { 
    // shared todo variable used to pass value between setTodo filter and actions
    var todo: Todo?    
    override func controller() {

    // sets before filter setTodo only for specified actions.
    beforeAction("setTodo", only: ["show", "edit", "update", "destroy"])

    // render all Todo instances with Index template (in Views/Todos/Index.html.stencil)
    action("index") { request in
        let todos = ["todos": Todo.allAttributes()]
        return render("Todos/Index", todos)
    }

    // render Todo instance that was set in before filter
    action("show") { request in
        return render("Todos/Show", self.todo)
    }

    // render static New template
    action("new") { request in
        return render("Todos/New")
    }

    // render Todo instance's edit form
    action("edit") { request in
        return render("Todos/Edit", self.todo)
    } 

    // create new Todo instance and redirect to list of Todos 
    action("create") { request in
        Todo.create(request.params)
        return redirectTo("/todos")
    }
    
    // update Todo instance and redirect to updated Todo instance
    action("update") { request in
        self.todo!.update(request.params)
        return redirectTo("/todos/\(self.todo!.id)")
    }

    // destroy Todo instance
    action("destroy") { request in
        Todo.destroy(self.todo)
        return redirectTo("/todos")
    }

    // set todo shared variable to actions can use it
    filter("setTodo") { request in
        // Redirect to "/todos" list if Todo instance is not found 
        guard let t = Todo.find(request.params["id"]) else { return self.redirectTo("/todos") } 
        self.todo = t as? Todo
        // Run next filter or action
        return self.next
    }

}}

Controller Responders

respondTo allows to define multiple responders based client Accept header:

...
action("show") { request in
    return respondTo(request, [
        "html": { render("Todos/Show", self.todo) },
        "json": { renderJSON(self.todo) }
    ])
}
...

Controller Filters

Swifton Controllers support beforeAction and afterAction filters, which run filters before or after action correspodingly. Filter is a closure that returns Response?. Controller proceeds execution only if filter returns self.next (which is actually nil), otherwise it returns Response object and doesn't proceed execution of other filters and action.

filter("setTodo") { request in
    // Redirect to "/todos" list if Todo instance is not found
    guard let t = Todo.find(request.params["id"]) else { return self.redirectTo("/todos") }
    self.todo = t as? Todo
    // Run next filter or action
    return self.next
}

Models

Swifton is ORM agnostic web framework. You can use any ORM of your choice. Swifton comes with simple in-memory MemoryModel class that you can inherit and use for your apps. Simple as this:

class User: MemoryModel {
}

...

User.all.count // 0
var user = User.create(["name": "Saulius", "surname": "Grigaitis"])
User.all.count // 1
user["name"] // "Saulius"
user["surname"] // "Grigaitis"
user.update(["name": "James", "surname": "Bond"])
user["surname"] // "Bond"
User.destroy(user)
User.all.count // 0

Few options if you need persistence:

• PostgreSQL adapter.
• MySQL adapter.
• Fluent simple SQLite ORM.

Views

Swifton supports Mustache like templates via Stencil template language. View is rendered with controller's method render(template_path, object). Object needs either to conform to HTMLRenderable protocol, either be [String: Any] type where Any allows to pass complex structures.

<tbody>
  {% for todo in todos %}
    <tr>
      <td>{{ todo.title }}</td>
      <td>{{ todo.completed }}</td>
      <td><a href="/todos/{{ todo.id }}">Show</a></td>
      <td><a href="/todos/{{ todo.id }}/edit">Edit</a></td>
      <td><a data-confirm="Are you sure?" rel="nofollow" data-method="delete" href="/todos/{{ todo.id }}">Destroy</a></td>
    </tr>
  {% endfor %}
</tbody>

Views are loaded from Views directory by default, you can also change this default setting by changing value of SwiftonConfig.viewsDirectory (preferable in main.swift file). Currently views are not cached, so you don't need to restart server or recompile after views are changed.

Static assets (JavaScript, CSS, images etc.) are loaded from Public directory by default, you can also change this default setting by changing value of SwiftonConfig.publicDirectory (preferable in main.swift file).

JSON support

renderJSON(object) generates and returns JSON of an object. Object must conform to JSONRenderable protocol.

action("show") { request in
    return respondTo(request, [
        "html": { render("Todos/Show", self.todo) },
        "json": { renderJSON(self.todo) }
    ])
}

Middleware

main.swift is probably best place to put middleware. Simply wrap Router instance with your middleware, you can even nest multiple middlewares.

...
serve { request in
    router.respond(request) 
}
...

Application Server

Swifton comes with VeniceX based HTTP server. Swifton supports S4 HTTP standards for Swift so you can easily use any S4 supporting server.

Building for production

Build release configuration for better performance:

$ swift build --configuration release

Deployment

Heroku

Example TodoApp can be deployed to Heroku using the heroku-buildpack-swift.

Click the button below to automatically set up this example to run on your own Heroku account.

Docker

Swifton can be deployed with Docker. Some examples how to deploy it with Docker:

• TodoApp on EC2 Container Services (ECS) example
• Docker Container for the Apple's Swift programming language - docker-swift.