NetNewsWire/Shared/Secrets.swift.gyb

// Secrets.swift.gyb
%{
import os

def chunks(seq, size):
    return (seq[i:(i + size)] for i in range(0, len(seq), size))

def encode(string, salt):
    bytes = string.encode("UTF-8")
    return [ord(bytes[i]) ^ salt[i % len(salt)] for i in range(0, len(bytes))]

salt = [ord(byte) for byte in os.urandom(64)]
}%
enum Secrets {

  static var FeedWranglerClientKey: String {
      let encoded: [UInt8] = [
      % for chunk in chunks(encode(os.environ.get('FEED_WRANGLER_KEY'), salt), 8):
          ${"".join(["0x%02x, " % byte for byte in chunk])}
      % end
      ]

      return decode(encoded, salt: salt)
  }

  private static let salt: [UInt8] = [
  % for chunk in chunks(salt, 8):
    ${"".join(["0x%02x, " % byte for byte in chunk])}
  % end
  ]

  private static func decode(_ encoded: [UInt8], salt: [UInt8]) -> String {
    String(decoding: encoded.enumerated().map { (offset, element) in
        element ^ salt[offset % salt.count]
    }, as: UTF8.self)
  }
}