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https://github.com/skylab-inc/Lightning

A Swift Multiplatform Single-threaded Non-blocking Web and Networking Framework
https://github.com/skylab-inc/Lightning

asynchronous asynchronous-events edge frp functional-reactive-programming libdispatch lightning nodejs non-blocking non-blocking-sockets nonblocking reactivecocoa single-thread swift swift-package-manager swift4 tcp thread-safe

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A Swift Multiplatform Single-threaded Non-blocking Web and Networking Framework

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README 

        


Edge


Serverside non-blocking IO in Swift


Ask questions in our Slack channel!





# Lightning

##### (formerly Edge)



![Swift](http://img.shields.io/badge/swift-4.0.2-brightgreen.svg)

[![Build Status](https://travis-ci.org/skylab-inc/Lightning.svg?branch=master)](https://travis-ci.org/skylab-inc/Lightning)

[![codecov](https://codecov.io/gh/skylab-inc/Lightning/branch/master/graph/badge.svg)](https://codecov.io/gh/skylab-inc/Lightning)

[![Slack Status](https://slackin-on-edge.herokuapp.com/badge.svg)](https://slackin-on-edge.herokuapp.com)



#### Node

Lightning is an HTTP Server and TCP Client/Server framework written in Swift and inspired by [Node.js](https://nodejs.org). It runs on both OS X and Linux. Like Node.js, Lightning uses an **event-driven, non-blocking I/O model**. In the same way that Node.js uses [libuv](http://libuv.org) to implement this model, Lightning uses [libdispatch](https://github.com/apple/swift-corelibs-libdispatch). 



This makes Lightning fast, efficient, and most crutially **single-threaded** by default. You simply do not need to worry about locks/mutexes/semaphores/etc if you have server-side state. Of course, Lightning applications can make use of libdispatch to easily offload heavy processing to a background thread if necessary.



#### Reactive Programming

Lightning's event API embraces Functional Reactive Programming by generalizing the familiar concept of promises. This API is called [StreamKit](https://github.com/skylab-inc/StreamKit).



> StreamKit's architecture is inspired by both [ReactiveCocoa](https://github.com/ReactiveCocoa/ReactiveCocoa) and [RxSwift](https://github.com/ReactiveX/RxSwift).



##### Why did we reimplement?

* Lightning should be easy to use out of the box.

* Lightning is optimized for maximum performance, which requires careful tuning of the internals.

* The modified API is meant to be more similar to the familiar concepts of Futures and Promises.

* We don't want to be opinionated about any one framework. We want it to be easy to integate Lightning with either ReactiveCocoa or RxSwift.



>FRP, greatly simplies management of asynchronous events. The general concept is that we can build a spout which pushes out asynchronous events as they happen. Then we hookup a pipeline of transformations that operate on events and pass the transformed values along. We can even do things like merge streams in interesting ways! Take a look at some of these [operations](http://rxmarbles.com) or watch [this talk](https://www.youtube.com/watch?v=XRYN2xt11Ek) about how FRP is used at Netflix. 



# Installation



Lightning is available as a Swift 3/4 package. Simply add Lightning as a dependency to your Swift Package.



Swift 3

```Swift

import PackageDescription



let package = Package(

    name: "MyProject",

    dependencies: [

        .Package(url: "https://github.com/skylab-inc/Lightning.git", majorVersion: 0, minor: 3)

    ]

)

```

Swift 4

```Swift

// swift-tools-version:4.0

// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription



let package = Package(

    name: "MyProject",

    dependencies: [

        .package(url: "https://github.com/skylab-inc/Lightning.git", from: "0.3.0"),

    ]

)

```



# Usage



### Routing

```swift

import Lightning

import Foundation



// Create an API router.

let api = Router()



// Add a GET "/users" endpoint.

api.get("/users") { request in

    return Response(status: .ok)

}



// NOTE: Equivalent to `api.post("/auth/login")`

let auth = api.subrouter("/auth")

auth.post("/login") { request in

    return Response(status: .ok)

}



// Middleware to log all requests

// NOTE: Middleware is a simple as a map function or closure!

let app = Router()

app.map { request in

    print(request)

    return request

}



// Mount the API router under "/v1.0".

app.add("/v1.0", api)



// NOTE: Warnings on all unhandled requests. No more hanging clients!

app.any { _ in

    return Response(status: .notFound)

}



// Start the application.

app.start(host: "0.0.0.0", port: 3000)

```



### Raw HTTP

```swift

import Lightning

import Foundation



func handleRequest(request: Request) -> Response {

    print(String(bytes: request.body, encoding: .utf8)!)

    return try! Response(json: ["message": "Message received!"])

}



let server = HTTP.Server()

server.listen(host: "0.0.0.0", port: 3000).startWithNext { client in



    let requestStream = client.read()

    requestStream.map(handleRequest).onNext{ response in

        client.write(response).start()

    }



    requestStream.onFailed { clientError in

        print("Oh no, there was an error! \(clientError)")

    }



    requestStream.onCompleted {

        print("Goodbye \(client)!")

    }



    requestStream.start()

}



RunLoop.runAll()

```



### TCP

```Swift



import Lightning

import Foundation



let server = try! TCP.Server()

try! server.bind(host: "0.0.0.0", port: 50000)

    

server.listen().startWithNext { connection in

    let byteStream = connection.read()

    let strings = byteStream.map { String(bytes: $0, encoding: .utf8)! }

    

    strings.onNext { message in

        print("Client \(connection) says \"\(message)\"!")

    }

    

    strings.onFailed { error in

        print("Oh no, there was an error! \(error)")

    }

    

    strings.onCompleted {

        print("Goodbye \(connection)!")

    }

    

    strings.start()

}



RunLoop.runAll()

```



### Lightning is not Node.js



Lightning is not meant to fulfill all of the roles of Node.js. Node.js is a JavaScript runtime, while Lightning is a TCP/Web server framework. The Swift compiler and package manager, combined with third-party Swift packages, make it unnecessary to build that functionality into Lightning.