ilyapuchka/swiftniomock

Usage

In the test create an instance of the server and start it in the setUp method and provide it with a middleware to handle requests. In the tearDown method stop the server.

override func setUp() {
    server = Server(port: 8080, handler: <#Middleware#>)
    try! server.start()
}

override func tearDown() {
    try! server.stop()
    server = nil
}

A middleware is a function that is based on an incoming request can modify a response.

typealias Middleware = (
    _ request: Server.HTTPHandler.Request,
    _ response: Server.HTTPHandler.Response,
    _ next: @escaping () -> Void
) -> Void

When middleware function is done with response it should call the next closure (it's fine to call it asynchronously) that is passed to it to return control to the server. You can write your own middleware or use those provided by SwiftNIOMock, which are redirect, router and delay. Here is an example of a simple middleware that echoes back any incoming request:

func echo(
    request: Server.HTTPHandler.Request,
    response: Server.HTTPHandler.Response,
    next: @escaping () -> Void
) {
    response.statusCode = .ok
    response.body = request.body
    next()
}

redirect middleware allows you to redirect incoming requests and intercept responses. It also accepts an instance of URLSession (URLSession.shared session by default) that it will use to perform a request, which allows it to record & replay all requests. Check out SwiftNIOMockExampleUITests.swift to see the example of how to use SwiftNIOMock in record & replay mode powered by Vinyl.

func redirect(
    session: URLSession = URLSession.shared,
    request override: @escaping (Server.HTTPHandler.Request) -> Server.HTTPHandler.Request,
    response intercept: @escaping (Server.HTTPHandler.Response) -> Void = { _ in }
) -> Middleware

router middleware allows you to return arbitrary middleware based on a request, i.e. its method and path. If request can't be handled a fallback middleware passed as notFound parameter will be used.

func router(
    route: @escaping (Server.HTTPHandler.Request) -> Middleware?,
    notFound: @escaping Middleware
) -> Middleware

To see an example of usage SwiftNIOMock in UI tests check SwiftNIOMockExample.

Routing

While you can use the router function to create a routing middleware for the mock server on the practice it is a good idea to break it down into smaller services. For that you can use Service type:

let fooService = Service {
    route({ $0.head.uri == "/foo" }) { (request, response, next) in
        response.sendString(.ok, value: "Foo")
        next()
    }
}
let barService = Service {
    route({ $0.head.uri == "/bar" }) { (request, response, next) in
        response.sendString(.ok, value: "Bar")
        next()
    }
}

let router = SwiftNIOMock.router(services: [
    fooService,
    barService
])

You can as well implement your own service by subclassing Service:

class HelloService: Service {
    override init() {
        super.init()
        routes {
            route({ $0.head.uri == "/helloworld" }) { (request, response, next) in
                response.sendString(.ok, value: "Hello World!")
                next()
            }
        }
    }
}
let helloService = HelloService()
let router = SwiftNIOMock.router(services: [helloService])

You can register routes using closure predicates as in above examples or using URLFormat:

import URLFormat

routes {
    route(GET/.helloworld) { (request, response, next) in
        response.sendString(.ok, value: "Hello World!")
        next()
    }
}

You can also use a shorthand syntax to bind routes to a service KeyPath or a function with Encodable return value type:

class HelloService: Service {
    let users: [String]
    
    func user(byName name: String) -> String? {
        users.first { $0 == name }
    }
    
    init(users: [String]) {
        self.users = users
        super.init()
        
        routes {
            GET/.users == \HelloService.users
            GET/.users/.string == HelloService.user(byName:)
        }
    }
}

As routes are bound to key paths or functions you can mutate the state of your service and these changes will be reflected in the later responses.

When binding a route to a function its parameters types must match URLFormat type, i.e. URLFormat<((String, String), Int)> can be only bound to a function (String, String, Int) -> T where T: Encodable. Additionally you can add a Server.HTTPHandler.Request parameter as the last parameter of the function to access a request body data.

Installation

import PackageDescription

let package = Package(
    dependencies: [
        .package(url: "https://github.com/ilyapuchka/SwiftNIOMock.git", .branch("master")),
    ]
)

Package Metadata

Repository: ilyapuchka/swiftniomock

Default branch: master

README: README.md