Core NFC (iOS 13.0 以降) で楽天Edy、nanaco、WAON の残高を読み取る

ViewController.swift

//
//  ViewController.swift
//  emoneyReader
//
//  Created by treastrain on 2019/12/11.
//  Copyright © 2019 treastrain / Tanaka Ryoga. All rights reserved.
//

import UIKit
import CoreNFC

class ViewController: UIViewController, NFCTagReaderSessionDelegate {
    
    var session: NFCTagReaderSession?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        guard NFCTagReaderSession.readingAvailable else {
            print("NFC タグの読み取りに非対応のデバイス")
            return
        }
        
        self.session = NFCTagReaderSession(pollingOption: .iso18092, delegate: self)
        self.session?.alertMessage = "カードの上に iPhone の上部を載せてください"
        self.session?.begin()
    }
    
    func tagReaderSessionDidBecomeActive(_ session: NFCTagReaderSession) {
        print("tagReaderSessionDidBecomeActive(_:)")
    }
    
    func tagReaderSession(_ session: NFCTagReaderSession, didInvalidateWithError error: Error) {
        let readerError = error as! NFCReaderError
        print(readerError.code, readerError.localizedDescription)
    }
    
    func tagReaderSession(_ session: NFCTagReaderSession, didDetect tags: [NFCTag]) {
        print("tagReaderSession(_:didDetect:)")
        
        let tag = tags.first!
        session.connect(to: tag) { (error) in
            if let error = error {
                session.invalidate(errorMessage: error.localizedDescription)
                return
            }
            
            guard case NFCTag.feliCa(let feliCaTag) = tag else {
                session.invalidate(errorMessage: "FeliCa ではない")
                return
            }
            
            session.alertMessage = "カードを読み取っています…"
            
            let idm = feliCaTag.currentIDm.map { String(format: "%.2hhx", $0) }.joined()
            print("IDm:", idm)
            
            /// FeliCa サービスコード
            let rakutenEdyServiceCode = Data([0x13, 0x17].reversed())
            let nanacoServiceCode = Data([0x55, 0x97].reversed())
            let waonServiceCode = Data([0x68, 0x17].reversed())
            let serviceCodeList = [rakutenEdyServiceCode]
            
            /// ブロック数
            let blocks = 1
            let blockList = (0..<blocks).map { (block) -> Data in
                Data([0x80, UInt8(block)])
            }
            
            feliCaTag.readWithoutEncryption(serviceCodeList: serviceCodeList, blockList: blockList) { (status1, status2, blockData, error) in
                if let error = error {
                    session.invalidate(errorMessage: error.localizedDescription)
                    return
                }
                
                guard status1 == 0x00, status2 == 0x00 else {
                    print("ステータスフラグがエラーを示しています", status1, status2)
                    session.invalidate(errorMessage: "ステータスフラグがエラーを示しています s1:\(status1), s2:\(status2)")
                    return
                }
                
                let data = blockData.first!
                let balance = data.toIntReversed(0, 3)
                
                print(data as NSData)
                print("残高: ¥\(balance)")
                session.alertMessage = "残高: ¥\(balance)"
                session.invalidate()
            }
        }
    }
}

extension Data {
    /// https://github.com/treastrain/TRETJapanNFCReader/blob/master/TRETJapanNFCReader/Extensions.swift#L112
    func toIntReversed(_ startIndex: Int, _ endIndex: Int) -> Int {
        var s = 0
        for (n, i) in (startIndex...endIndex).enumerated() {
            s += Int(self[i]) << (n * 8)
        }
        return s
    }
}