taler-ios

SwiftNFC.swift (5919B)

---

 //  MIT License
 //  Copyright © Ming
 //  https://github.com/1998code/SwiftNFC
 //
 //  Permission is hereby granted, free of charge, to any person obtaining a copy of this software
 //  and associated documentation files (the "Software"), to deal in the Software without restriction,
 //  including without limitation the rights to use, copy, modify, merge, publish, distribute,
 //  sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 //  furnished to do so, subject to the following conditions:
 //
 //  The above copyright notice and this permission notice shall be included in all copies or
 //  substantial portions of the Software.
 //
 //  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 //  BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 //  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 //  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 //
 /**
  * @author Marc Stibane
  */
 import SwiftUI
 @preconcurrency import CoreNFC
 
 fileprivate let comment: StaticString = "NFC tag reader"
 
 public class NFCWriter: NSObject, ObservableObject, NFCNDEFReaderSessionDelegate {
     
     public var startAlert = String(localized: "Hold your iPhone near the tag.", comment: comment)
     public var endAlert = EMPTYSTRING
     public var msg = EMPTYSTRING
     public var type = "T"   // T=Text - U=URL
     public var data: Data? = nil
 
     public var session: NFCNDEFReaderSession?
     
     public func write(_ data: Data? = nil) {
         guard NFCNDEFReaderSession.readingAvailable else {
             print("  ❗️Error readingAvailable")
             return
         }
         self.data = data
         session = NFCNDEFReaderSession(delegate: self, queue: nil, invalidateAfterFirstRead: false)
         if let session {
             session.alertMessage = self.startAlert
             session.begin()
         } else {
             print("  ❗️Error NFCNDEFReaderSession")
         }
     }
     
     public func readerSession(_ session: NFCNDEFReaderSession, didDetectNDEFs messages: [NFCNDEFMessage]) {
         // Do not add code in this function.
         // This method isn't called when you provide `reader(_:didDetect:)`.
 //        print("  ❗️didDetectNDEFs", messages)
     }
 
     public func readerSession(_ session: NFCNDEFReaderSession, didDetect tags: [NFCNDEFTag]) {
         if tags.count > 1 {
             let retryInterval = DispatchTimeInterval.milliseconds(500)
             session.alertMessage = String(localized: "Detected more than 1 tag. Please try again.", comment: comment)
             DispatchQueue.global().asyncAfter(deadline: .now() + retryInterval, execute: {
                 session.restartPolling()
             })
             return
         }
         
         let tag = tags.first!
         session.connect(to: tag) { (error: Error?) in
             if nil != error {
                 print("  ❗️Connection error: \(String(describing: error))")
                 session.alertMessage = String(localized: "Unable to connect to tag.", comment: comment)
                 session.invalidate()
                 return
             }
             
             tag.queryNDEFStatus() { (ndefStatus: NFCNDEFStatus, capacity: Int, error: Error?) in
                 guard error == nil else {
                     session.alertMessage = "Unable to query the status of the tag."
                     session.invalidate()
                     return
                 }
 
                 switch ndefStatus {
                 case .notSupported:
                     session.alertMessage = "Tag is not NDEF compliant."
                     session.invalidate()
                 case .readOnly:
                     session.alertMessage = "Read only tag detected."
                     session.invalidate()
                 case .readWrite:
                     let payload: NFCNDEFPayload?
                     if self.type == "T" {       // TAG
                         payload = NFCNDEFPayload.init(format: .nfcWellKnown,
                                                         type: Data("\(self.type)".utf8),
                                                   identifier: Data(),
                                                      payload: self.data ?? Data("\(self.msg)".utf8)
                         )
                     } else {
                         payload = NFCNDEFPayload.wellKnownTypeURIPayload(string: "\(self.msg)")
                     }
                     let message = NFCNDEFMessage(records: [payload].compactMap({ $0 }))
                     tag.writeNDEF(message) { (error: Error?) in
                         if nil != error {
                             session.alertMessage = String(localized: "Write to tag failed: \(error!)", comment: comment)
                         } else {
                             session.alertMessage = self.endAlert != EMPTYSTRING ? self.endAlert
                                                  : String(localized: "Write \(self.msg) to tag successful.", comment: comment)
                         }
                         session.invalidate()
                     }
                 @unknown default:
                     session.alertMessage = String(localized: "Unknown tag status.", comment: comment)
                     session.invalidate()
                 }
             }
         }
     }
     
     public func readerSessionDidBecomeActive(_ session: NFCNDEFReaderSession) {
         session.alertMessage = String(localized: "Reading Tag...", comment: comment)
     }
 
     public func readerSession(_ session: NFCNDEFReaderSession, didInvalidateWithError error: Error) {
         print("  ❗️Session did invalidate with error: \(error)")
         self.session = nil
     }
 }