Live 🐧 server running Demo 
Documentation 
<h5 align="right"><a href="http://demo.swiftexpress.io/">Live 🐧 server running Demo <img src="https://cdn0.iconfinder.com/data/icons/glyphpack/34/play-circle-32.png" height=16/></a></h5>
<h5 align="right"><a href="http://swiftexpress.io/">Eating our own dog food <img src="https://cdn0.iconfinder.com/data/icons/glyphpack/147/globe-full-32.png" height=16/></a></h5>
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</p>
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Being perfectionists, we took the best from what we think is the best: power of Play Framework and simplicity of Express.js
Express is an asynchronous, simple, powerful, yet unopinionated web application server written in Swift
Getting started
First make sure, please, you have followed the installation section steps.
Create a project:
swift-express init HelloExpress
cd HelloExpress
swift-express bootstrap
open HelloExpress.xcodeproj
Create new API:
app.get("/myecho") { request in
.ok(request.query["message"]?.first)
}
Run from xCode or command line with:
swift-express build
swift-express run
Test it in the browser: http://localhost:9999/myecho?message=Hello
A complete Swift Express command line documentation can be found here: https://github.com/crossroadlabs/ExpressCommandLine
Installation
OS X 
First install the following components (if you have not yet):
- XCode 7.2 or higher
- Homebrew the latest available version
- Command Line tools: run
xcode-select --installin terminal
Run the following in terminal:
brew tap crossroadlabs/tap
brew install swift-express
Linux 
For instructions on how to get Express installed on Linux, please, refer to the installation section in the ducumentation.
Examples
Create a project as it is described in the getting started section. Now you can start playing with examples.
All the examples can be found in Demo project inside the main repo.
Hello Express:
app.get("/hello") { request in
.ok(AnyContent(str: "<h1>Hello Express!!!</h1>", contentType: "text/html"))
}
Launch the app and follow the link: http://localhost:9999/hello?message=Hello
Synchronous vs Asynchronous
If you don't know what this is you might want to better skip it for now to the next section: URL params. To get more information see this first. We have our APIs based on Future pattern. Our implementation is based on BrightFutures, thanks @Thomvis!
Express can handle it both ways. All your syncronous code will be executed in a separate queue in a traditional way, so if you are a fan of this approach - it will work (like in "Hello Express" example above).
Still if you want to benefit from asynchronicity, we provide a very powerful API set that accepts futures as result of your handler.
Let's assume you have following function somewhere:
func calcFactorial(num:Double) -> Future<Double, AnyError>
it's a purely asyncronous function that returns future. It would be really nice if it could be handled asynchronously as well in a nice functional way. Here is an example of how it could be done.
// (request -> Future<Action<AnyContent>, AnyError> in) - this is required to tell swift you want to return a Future
// hopefully inference in swift will get better eventually and just "request in" will be enough
app.get("/factorial/:num(\\d+)") { request -> Future<Action<AnyContent>, AnyError> in
// get the number from the url
let num = request.params["num"].flatMap{Double($0)}.getOrElse(0)
// get the factorial Future. Returns immediately - non-blocking
let factorial = calcFactorial(num)
//map the result of future to Express Action
let future = factorial.map { fac in
Action.ok(String(fac))
}
//return the future
return future
}
URL params
Let's get our echo example from Getting Started a bit further. Our routing engine, which is largely based on NodeJS analog path-to-regex. You can read the complete documentation on how to use path patterns here. Now an example with URL param:
//:param - this is how you define a part of URL you want to receive through request object
app.get("/echo/:param") { request in
//here you get the param from request: request.params["param"]
.ok(request.params["param"])
}
Serving static files
app.get("/:file+", action: StaticAction(path: "public", param:"file"))
The code above tells Express to serve all static files from the public folder recursively. If you want to serve just the first level in folder, use:
app.get("/:file", action: StaticAction(path: "public", param:"file"))
The difference is just in the pattern: /:file versus /:file+. For more information see our routing section.
Serving JSON requests
First of all we need to register the JSON view in the system:
//now we can refer to this view by name
app.views.register(JsonView())
Let's say we want to build a simple API for users registration. We want our API consumers to POST to /api/user a JSON object and get a JSON response back.
app.post("/api/user") { request in
//check if JSON has arrived
guard let json = request.body?.asJSON() else {
return Action.ok("Invalid request")
}
//check if JSON object has username field
guard let username = json["username"].string else {
return Action.ok("Invalid request")
}
//compose the response as a simple dictionary
let response =
["status": "ok",
"description": "User with username '" + username + "' created succesfully"]
//render disctionary as json (remember the one we've registered above?)
return .render(JsonView.name, context: response)
}
Lines above will do the job. Post this JSON:
{
"username": "swiftexpress"
}
to our api URL: http://localhost:9999/api/user (don't forget application/json content type header) and you will get this response:
{
"status": "ok",
"description": "User with username 'swiftexpress' created succesfully"
}
Using template engine
First of all you need to switch the template engine on:
//we recommend mustache template engine
app.views.register(StencilViewEngine())
Now create a file called hello.stencil in the views directory:
<html>
<body>
<h1>Hello from Stencil: {{user}}</h1>
</body>
</html>
Add a new request handler:
//user as an url param
app.get("/hello/:user.html") { request in
//get user
let user = request.params["user"]
//if there is a user - create our context. If there is no user, context will remain nil
let context = user.map {["user": $0]}
//render our template named "hello"
return .render("hello", context: context)
}
Now follow the link to see the result: http://localhost:9999/hello/express.html
If you want more, please, visit our documentation page
Ideology behind
Taking the best of Swift
Swift essentially is a new generation programming language combining simplicity and all the modern stuff like functional programming.
We were inspired (and thus influenced) mainly by two modern web frameworks: Express.js and Play. So, we are trying to combine the best of both worlds taking simplicity from Express.js and modern robust approach of Play
Let us know if we are on the right path! Influence the project, create feature requests, API change requests and so on. While we are in our early stages, it's easy to change. We are open to suggestions!
Features
-
🐧 Linux support with and without Dispatch - 100% asynchronous (Future-based API)
- Flexible and extensible
- Full MVC support
- Swift 2.1 and 2.2 compatible
- Simple routing mechanism
- Request handlers chaining
- Typesafe Error Handlers
- Templates: Stencil and Mustache
- Built-in JSON support
- Easy creation of RESTful APIs
- Built-in static files serving
- Multiple contents types built-in support
And heah, the most important feature: Highly passionate development team
Roadmap
- v0.4: stable version with Swift 3.0
- v0.5: proper streaming
- v0.6: new core (based on Reactive Swift)
- v0.7: more content types available out of the box
- v0.8: Web Sockets
- v0.9: hot code reload
- v1.0: hit the production!
Changelog
-
v0.4: Swift 3.0
- Ported Express to Swift 3.0
- Moved to Reactive Swift foundation (Execution contexts, Futures, etc.)
- Wrapped libevent as an ExecutionContext
- Dropped Carthage support
-
v0.3: linux support
- Runs on linux with and without Dispatch support (see installation section and building in production)
- FormUrlEncoded ContentType support
- Merged Query (params from both query string and form-url-encoded body merged together)
- Utility methods (redirect, status, etc)
- Stencil Templete Engine Support
- Replaced SwiftyJSON with TidyJSON
- Typesafe Error Handlers
- Better Demo app
-
v0.2.1: minor changes
- Swift modules are installed via Carthage
- Enabled binary builds on OS X
-
v0.2: Solid OS X release
- Much better routing APIs
- Advanced routing path patterns
- Possibility to use Regex for routing
- Greately improved README
- Some bugfixes
-
v0.1: Initial Public Release
- basic routing
- views and view engines (supports Mustache)
- JSON rendering as a view
- query parsing
- static files serving
Contributing
To get started, sign the Contributor License Agreement.
by Crossroad Labs
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