Swift scripts and macOS apps
Swift compiler 101, you may create, construct and run a Swift file utilizing the swiftc command. Contemplate the simplest Swift program that we are able to all think about in a foremost.swift file:
print("Hey world!")
In Swift if we wish to print one thing, we do not even should import the Basis framework, we are able to merely compile and run this piece of code by operating the next:
swiftc foremost.swift # compile foremost.swift
chmod +x foremost # add the executable permission
./foremost # run the binary
The excellent news that we are able to take this one step additional by auto-invoking the Swift compiler below the hood with a shebang.
#! /usr/bin/swift
print("Hey world!")
Now should you merely run the ./foremost.swift file it will print out the well-known “Hey world!” textual content. 👋
Because of the program-loader mechanism and naturally the Swift interpreter we are able to skip an additional step and run our single-source Swift code as straightforward as a daily shell script. The excellent news is that we are able to import all kind of system frameworks which might be a part of the Swift toolchain. With the assistance of Basis we are able to construct fairly helpful or fully ineffective command line utilities.
#!/usr/bin/env swift
import Basis
import Dispatch
guard CommandLine.arguments.rely == 2 else {
fatalError("Invalid arguments")
}
let urlString = CommandLine.arguments[1]
guard let url = URL(string: urlString) else {
fatalError("Invalid URL")
}
struct Todo: Codable {
let title: String
let accomplished: Bool
}
let process = URLSession.shared.dataTask(with: url) { knowledge, response, error in
if let error = error {
fatalError("Error: (error.localizedDescription)")
}
guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
fatalError("Error: invalid HTTP response code")
}
guard let knowledge = knowledge else {
fatalError("Error: lacking response knowledge")
}
do {
let decoder = JSONDecoder()
let todos = attempt decoder.decode([Todo].self, from: knowledge)
print("Listing of todos:")
print(todos.map { " - [" + ($0.completed ? "✅" : "❌") + "] ($0.title)" }.joined(separator: "n"))
exit(0)
}
catch {
fatalError("Error: (error.localizedDescription)")
}
}
process.resume()
dispatchMain()
In case you name this instance with a URL that may return an inventory of todos it will print a pleasant listing of the objects.
./foremost.swift https://jsonplaceholder.typicode.com/todos
Sure, you may say that this script is totally ineffective, however in my view it is a tremendous demo app, because it covers easy methods to examine command line arguments (CommandLine.arguments), it additionally exhibits you easy methods to wait (dispatchMain) for an async process, similar to a HTTP name via the community utilizing the URLSession API to complete and exit utilizing the precise methodology when one thing fails (fatalError) or should you attain the top of execution (exit(0)). Just some traces of code, but it surely accommodates a lot data.
Have you ever seen the brand new shebang? You probably have a number of Swift variations put in in your system, you need to use the env shebang to go along with the primary one which’s accessible in your PATH.
It isn’t simply Basis, however you may import AppKit and even SwiftUI. Effectively, not below Linux in fact, since these frameworks are solely accessible for macOS plus you’ll need Xcode put in in your system, since some stuff in Swift the toolchain continues to be tied to the IDE, however why? 😢
Anyway, again to the subject, here is the boilerplate code for a macOS software Swift script that may be began from the Terminal with one easy ./foremost.swift command and nothing extra.
#!/usr/bin/env swift
import AppKit
import SwiftUI
@accessible(macOS 10.15, *)
struct HelloView: View {
var physique: some View {
Textual content("Hey world!")
}
}
@accessible(macOS 10.15, *)
class WindowDelegate: NSObject, NSWindowDelegate {
func windowWillClose(_ notification: Notification) {
NSApplication.shared.terminate(0)
}
}
@accessible(macOS 10.15, *)
class AppDelegate: NSObject, NSApplicationDelegate {
let window = NSWindow()
let windowDelegate = WindowDelegate()
func applicationDidFinishLaunching(_ notification: Notification) {
let appMenu = NSMenuItem()
appMenu.submenu = NSMenu()
appMenu.submenu?.addItem(NSMenuItem(title: "Stop", motion: #selector(NSApplication.terminate(_:)), keyEquivalent: "q"))
let mainMenu = NSMenu(title: "My Swift Script")
mainMenu.addItem(appMenu)
NSApplication.shared.mainMenu = mainMenu
let dimension = CGSize(width: 480, peak: 270)
window.setContentSize(dimension)
window.styleMask = [.closable, .miniaturizable, .resizable, .titled]
window.delegate = windowDelegate
window.title = "My Swift Script"
let view = NSHostingView(rootView: HelloView())
view.body = CGRect(origin: .zero, dimension: dimension)
view.autoresizingMask = [.height, .width]
window.contentView!.addSubview(view)
window.heart()
window.makeKeyAndOrderFront(window)
NSApp.setActivationPolicy(.common)
NSApp.activate(ignoringOtherApps: true)
}
}
let app = NSApplication.shared
let delegate = AppDelegate()
app.delegate = delegate
app.run()
Particular thanks goes to karwa for the unique gist. Additionally in case you are into Storyboard-less macOS app improvement, it is best to undoubtedly check out this text by @kicsipixel. These assets helped me lots to place collectively what I wanted. I nonetheless needed to prolong the gist with a correct menu setup and the activation coverage, however now this model acts like a real-world macOS software that works like a appeal. There is just one challenge right here… the script file is getting crowded. 🙈
Swift Bundle Supervisor and macOS apps
So, if we comply with the identical logic, which means we are able to construct an executable package deal that may invoke AppKit associated stuff utilizing the Swift Bundle Supervisor. Straightforward as a pie. 🥧
mkdir MyApp
cd MyApp
swift package deal init --type=executable
Now we are able to separate the elements into standalone information, we are able to additionally take away the provision checking, since we will add a platform constraint utilizing our Bundle.swift manifest file. If you do not know a lot about how the Swift Bundle Supervisor works, please learn my SPM tutorial, or in case you are merely curious in regards to the construction of a Bundle.swift file, you may learn my article in regards to the Swift Bundle manifest file. Let’s begin with the manifest updates.
import PackageDescription
let package deal = Bundle(
title: "MyApp",
platforms: [
.macOS(.v10_15)
],
dependencies: [
],
targets: [
.target(name: "MyApp", dependencies: []),
.testTarget(title: "MyAppTests", dependencies: ["MyApp"]),
]
)
Now we are able to place the HelloView struct into a brand new HelloView.swift file.
import SwiftUI
struct HelloView: View {
var physique: some View {
Textual content("Hey world!")
}
}
The window delegate can have its personal place inside a WindowDelegate.swift file.
import AppKit
class WindowDelegate: NSObject, NSWindowDelegate {
func windowWillClose(_ notification: Notification) {
NSApplication.shared.terminate(0)
}
}
We will apply the identical factor to the AppDelegate class.
import AppKit
import SwiftUI
class AppDelegate: NSObject, NSApplicationDelegate {
let window = NSWindow()
let windowDelegate = WindowDelegate()
func applicationDidFinishLaunching(_ notification: Notification) {
let appMenu = NSMenuItem()
appMenu.submenu = NSMenu()
appMenu.submenu?.addItem(NSMenuItem(title: "Stop", motion: #selector(NSApplication.terminate(_:)), keyEquivalent: "q"))
let mainMenu = NSMenu(title: "My Swift Script")
mainMenu.addItem(appMenu)
NSApplication.shared.mainMenu = mainMenu
let dimension = CGSize(width: 480, peak: 270)
window.setContentSize(dimension)
window.styleMask = [.closable, .miniaturizable, .resizable, .titled]
window.delegate = windowDelegate
window.title = "My Swift Script"
let view = NSHostingView(rootView: HelloView())
view.body = CGRect(origin: .zero, dimension: dimension)
view.autoresizingMask = [.height, .width]
window.contentView!.addSubview(view)
window.heart()
window.makeKeyAndOrderFront(window)
NSApp.setActivationPolicy(.common)
NSApp.activate(ignoringOtherApps: true)
}
}
Lastly we are able to replace the principle.swift file and provoke every little thing that must be completed.
import AppKit
let app = NSApplication.shared
let delegate = AppDelegate()
app.delegate = delegate
app.run()
The excellent news is that this strategy works, so you may develop, construct and run apps domestically, however sadly you may’t submit them to the Mac App Retailer, because the last software package deal will not seem like an actual macOS bundle. The binary just isn’t code signed, plus you will want an actual macOS goal in Xcode to submit the applying. Then why trouble with this strategy?
Effectively, simply because it’s enjoyable and I may even keep away from utilizing Xcode with the assistance of SourceKit-LSP and a few Editor configuration. One of the best half is that SourceKit-LSP is now a part of Xcode, so you do not have to put in something particular, simply configure your favourite IDE and begin coding.
You may as well bundle assets, since this function is obtainable from Swift 5.3, and use them via the Bundle.module variable if wanted. I already tried this, works fairly nicely, and it’s so a lot enjoyable to develop apps for the mac with out the additional overhead that Xcode comes with. 🥳
