A quick and dirty playground/script to get the current device's public IP address, validate it, and print it

get-public-ip.swift

import Foundation
import Network

/// A quick and dirty playground/script to get the current device's public IP address, validate it, and print it

let url = URL(string: "https://checkip.amazonaws.com")!
var publicIPAddress: IPAddress?

URLSession.shared.dataTask(with: url) { (data, response, error) in
	guard let data = data,
		  let httpResponse = response as? HTTPURLResponse,
		  200..<300 ~= httpResponse.statusCode else {
		return
	}

	guard let responseString = String(data: data, encoding: .utf8) else { return }
	var trimmedResponseString = responseString.trimmingCharacters(in: .whitespacesAndNewlines)

	// The returned value from AWS's public IP checker can return a comma separated list of IPs.
	// In that case, the final value is the canonical public IP, so we use that one
	// source: https://stackoverflow.com/questions/52618096/under-what-circumstances-does-checkip-amazonaws-com-return-multiple-addresses?noredirect=1&lq=1
	if trimmedResponseString.contains(",") {
		if let lastSplit = trimmedResponseString.split(separator: ",").last {
			trimmedResponseString = String(lastSplit)
		}
	}

	// Validate the returned string as an IP address
	if let ipv4Address = IPv4Address(trimmedResponseString) {
		print("Your IP address is an IPv4 address with the following value:", ipv4Address)
		publicIPAddress = ipv4Address
	} else if let ipv6Address = IPv6Address(trimmedResponseString) {
		print("Your IP address is an IPv6 address with the following value:", ipv6Address)
		publicIPAddress = ipv6Address
	} else {
		print("\(trimmedResponseString) is not a valid IP address")
	}
}.resume()