Gets easily version of given gem with Swifty and decodable.

GetFastlaneVersion.swift

#!/usr/bin/swift
// Use this script to get name and version of gem passed as first argument
//
// Example usage: `swift GetFastlaneVersion.swift fastlane 1.0.2`
//
// Arguments: - `gem` - The name of gem you want to inspect.
//            - `version` - The version you want to compare against the repo
//
// Because whole script runs in one thread, we need to use Semaphore to hold the thread until
// It finishes the asynch URLRequest. No mutex sorry 😔
//

import Foundation

// MARK: Safe Bounds of array:

extension Array {
    func at(index: Int) -> Element? {
        guard (0...self.count - 1).contains(index) else { return nil }
        return self[index]
    }
}

// MARK: Gem struct
struct Gem: Decodable {
    let name: String
    let version: String
}

// MARK: GLobal properties
let semaphore = DispatchSemaphore(value: 0)
let gemName = CommandLine.arguments.at(index: 1)
let currentFastlaneVersion = CommandLine.arguments.at(index: 2)

// MARK: Implementation
if CommandLine.arguments.count > 1,
let gemName = gemName,
let currentFastlaneVersion = currentFastlaneVersion {


    let url = URL(string: "https://rubygems.org/api/v1/gems/\(gemName).json")!
    let req = URLSession.shared.dataTask(with: url) { data, _, error in

        print("Getting request...")
        if let error = error {
            print("❌ An Error ocurred: \(error)")
            semaphore.signal()
            return
        }

        guard let data = data,
            let gem = try? JSONDecoder().decode(Gem.self, from: data)
            else { print("❌ Couldn't decode gem info."); semaphore.signal(); return }

        if gem.version == currentFastlaneVersion {
            print(" 🚀 You are all setup, your Fastlane is up to date")
        } else {
            print("❗️Your actual Fastlane installation is: \(currentFastlaneVersion), the most recent Fastlane version is \(gem.version)")
            print("❗️Please consider update")
        }
        semaphore.signal()
    }
    req.resume()

} else {
    print("❌ Please specify the gem name and current version as arguments.")
}

let timeout = DispatchTime.now() + DispatchTimeInterval.milliseconds(Int(60.0 * 1000.0)) // Overkill 😅
_ = semaphore.wait(timeout: timeout)