Newbie’s information to server-side Swift utilizing the Hummingbird framework

Swift on the Server in 2023

Three years in the past I began to deal with Vapor, the preferred web-framework written in Swift, which served me very nicely through the years, however now it’s time to begin a brand new chapter in my life.

As I discovered increasingly about how servers work I noticed that Vapor has it is personal professionals and cons. The neighborhood modified quite a bit in the course of the previous 3 years, some core members left and new individuals began to take care of the framework. I additionally had some struggles with the default template engine (Leaf) and not too long ago I began to show away from the summary database layer (Fluent) too. One other ache level for me is the rising variety of dependencies, I barely use websockets & multipart-kit, however Vapor has these dependencies by default and you’ll’t eliminate them. 😢

Vapor has some very nice issues to supply, and for most people it is nonetheless going to be an ideal selection for constructing backends for frontends (BFFs). For me, Vapor reached its limits and I needed to make use of one thing that feels a bit lighter. Somethings that’s modular, one thing that may be simply prolonged and suits my actual wants with out extra (unused) package deal dependencies.

This shiny new factor known as Hummingbird and it seems very promising. It was created by Adam Fowler who’s a member of the SSWG and likewise the principle writer of the Soto library (AWS Swift).

Hummingbird has a complete documentation obtainable on-line and a pleasant instance repository containing varied demo apps written utilizing the Hummingbird Swift server framework. I consider that the very best a part of the the framework is modularity & extensibility. By the way in which, Hummingbird works with out Basis, but it surely has extensions for Basis objects, it is a big plus for me, however possibly that is simply my private choice these days. Hummingbird could be prolonged simply, yow will discover some very helpful extensions underneath the Hummingbird undertaking web page, lengthy story quick it really works with Fluent and it is comparatively straightforward to get together with it you probably have some Vapor information… 🤔

Getting began with Hummingbird

To begin with, there isn’t a toolbox or command line utility to assist the kickoff course of, however you possibly can at all times obtain the examples repository and use one of many initiatives as a place to begin. Alternatively you possibly can set all the pieces up by hand, that is what we’ll do now. 🔨

So as to construct a brand new utility utilizing the Hummingbird framework you must create a brand new listing and initialize a brand new Swift package deal utilizing the next instructions:

mkdir server && cd $_
swift package deal init --type executable
open Bundle.swift

It will create a brand new Swift package deal and open the Bundle.swift file in Xcode. You need to use your personal editor in the event you do not like Xcode, however both manner you may have so as to add Hummingbird to your package deal manifest file as a dependency. We will setup an App goal for the applying itself, and a Server goal for the principle executable, which is able to use the applying and configure it as wanted.

import PackageDescription

let package deal = Bundle(
    identify: "server",
    platforms: [
        .macOS(.v10_15),
    ],
    dependencies: [
        .package(
            url: "https://github.com/hummingbird-project/hummingbird",
            from: "1.0.0"
        ),
        .package(
            url: "https://github.com/apple/swift-argument-parser",
            from: "1.0.0"
        ),
    ],
    targets: [
        .executableTarget(
            name: "Server",
            dependencies: [
                .product(
                    name: "ArgumentParser",
                    package: "swift-argument-parser"
                ),
                .target(name: "App"),
            ]
        ),
        .goal(
            identify: "App",
            dependencies: [
                .product(
                    name: "Hummingbird",
                    package: "hummingbird"
                ),
                .product(
                    name: "HummingbirdFoundation",
                    package: "hummingbird"
                ),
            ],
            swiftSettings: [
                .unsafeFlags(
                    ["-cross-module-optimization"],
                    .when(configuration: .launch)
                ),
            ]
        ),
        .testTarget(
            identify: "AppTests",
            dependencies: [
                .product(
                    name: "HummingbirdXCT",
                    package: "hummingbird"
                ),
                .target(name: "App"),
            ]
        ),
    ]
)

Please create the mandatory file and listing construction, as listed under, earlier than you proceed to the following steps. It is rather vital to call issues as they seem, in any other case SPM will not work and the undertaking will not compile. Anyway, the undertaking construction is kind-of Vapor-like as you possibly can see. 💧

.
├── Bundle.resolved
├── Bundle.swift
├── README.md
├── Sources
│ ├── App
│ │ └── HBApplication+Configure.swift
│ └── Server
│     └── primary.swift
└── Exams
    └── AppTests
        └── AppTests.swift

The subsequent step is to create the principle entry level for the applying. For this objective Hummingbird makes use of the Swift Argument Parser library. Place the next contents into the principle.swift file:

import ArgumentParser
import Hummingbird
import App

struct HummingbirdCommand: ParsableCommand {

    @Possibility(identify: .shortAndLong)
    var hostname: String = "127.0.0.1"

    @Possibility(identify: .shortAndLong)
    var port: Int = 8080

    func run() throws {
        let app = HBApplication(
            configuration: .init(
                handle: .hostname(hostname, port: port),
                serverName: "Hummingbird"
            )
        )
        attempt app.configure()
        attempt app.begin()
        app.wait()
    }
}

HummingbirdCommand.primary()

The HummingbirdCommand has two choices, you possibly can setup a customized hostname and port by offering these values as command line choices (I will present it afterward), the applying itself will setup the handle utilizing the enter after which it will begin listening on the desired port.

The configure technique comes from the App goal, that is the place you possibly can customise your server occasion, register route handlers and stuff like that, identical to you’ll do that in Vapor. The primary distinction is that Hummingbird makes use of the HB namespace, which is fairly helpful, and the configure technique is written as an extension. Let’s write it and register a fundamental route handler. 🧩

import Hummingbird
import HummingbirdFoundation

public extension HBApplication {

    func configure() throws {

        router.get("/") { _ in
            "Hey, world!"
        }
    }
}

That is it. Now you must be capable to run your server, you possibly can press the Play button in Xcode that’ll begin your utility or enter one of many following instructions into the Terminal utility:

# simply run the server
swift run Server

# customized hostname and port
swift run Server --port 3000
swift run Server --hostname 0.0.0.0 --port 3000

# quick model
swift run Server -p 3000
swift run Server -h 0.0.0.0 -p 3000

# set the log stage (https://github.com/apple/swift-log#log-levels)
LOG_LEVEL=discover swift run Server -p 3000

# make launch construct
swift construct -c launch

# copy launch construct to the native folder
cp .construct/launch/Server ./Server

# run the executable
LOG_LEVEL=discover ./Server -p 3000

You possibly can set these values in Xcode too, simply click on on the server scheme and choose the Edit Scheme… menu merchandise. Just remember to’re on the Run goal, displaying the Arguments tag. Merely provde the Arguments Handed On Launch choices to set a customized hostname or port and you’ll set the log stage by including a brand new merchandise into the Atmosphere Variables part.

If you would like to unit take a look at your utility, I’ve bought a excellent news for you. Hummingbird additionally comes with a pleasant utility instrument known as HummingbirdXCT, which you’ll simply setup & use if you would like to run some exams in opposition to your API. In our undertaking, merely alter the AppTests.swift file.

import Hummingbird
import HummingbirdXCT
import XCTest
@testable import App

remaining class AppTests: XCTestCase {
    
    func testHelloWorld() throws {
        let app = HBApplication(testing: .reside)
        attempt app.configure()

        attempt app.XCTStart()
        defer { app.XCTStop() }

        attempt app.XCTExecute(uri: "/", technique: .GET) { response in
            XCTAssertEqual(response.standing, .okay)

            let expectation = "Hey, world!"
            let res = response.physique.map { String(buffer: $0) }
            XCTAssertEqual(res, expectation)
        }
    }
}

As a substitute of making the applying from the principle entry level, we are able to arrange a brand new HBApplication occasion, import the App framework and name the configure technique on it. the XCT framework comes with a customized XCTStart and XCTStop technique, and you’ll execute HTTP requests utilizing the XCTExecute operate. The response is out there in a completion block and it is doable to look at the standing code and extract the physique utilizing a handy String initializer.

As you possibly can see Hummingbird is sort of much like Vapor, but it surely’s light-weight and you’ll nonetheless add these additional issues to your server when it’s wanted. Hummingbird appears like the following iteration of Vapor. I actually do not know if Vapor 5, goes to repair the problems I am at the moment having with the framework or not, however I do not actually care, as a result of that launch will not occur anytime quickly.