Merge pull request #73 from IdeasOnCanvas/enhancement/relaxDateParsing

Relax date parsing

AppReceiptValidator/AppReceiptValidator Tests Shared/ReceiptDateFormatterTests.swift

@@ -0,0 +1,28 @@
+//
+//  ReceiptDateFormatterTests.swift
+//  AppReceiptValidator
+//
+//  Created by Hannes Oud on 09.10.20.
+//  Copyright © 2020 IdeasOnCanvas GmbH. All rights reserved.
+//
+
+import AppReceiptValidator
+import Foundation
+import XCTest
+
+
+final class ReceiptDateFormatterTests: XCTestCase {
+
+    func testDateFormatting() throws {
+        let dateStrings = [
+            "2020-01-01T12:00:00Z",
+            "2020-01-01T12:00:00.123Z",
+            "2020-01-01T12:00:00.999Z",
+            "2020-01-01T12:00:01Z"
+        ]
+        for dateString in dateStrings {
+            let parsed = try XCTUnwrap(AppReceiptValidator.ReceiptDateFormatter.date(from: dateString))
+            XCTAssertEqual(AppReceiptValidator.ReceiptDateFormatter.string(from: parsed), dateString)
+        }
+    }
+}

AppReceiptValidator/AppReceiptValidator.xcodeproj/project.pbxproj

@@ -9,6 +9,8 @@
 /* Begin PBXBuildFile section */
 		D114544621A6BDE6001BEC61 /* DeviceIdentifierTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D114544521A6BDE6001BEC61 /* DeviceIdentifierTests.swift */; };
 		D114544721A6BDE6001BEC61 /* DeviceIdentifierTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D114544521A6BDE6001BEC61 /* DeviceIdentifierTests.swift */; };
+		D11B81CF2530687D00E19863 /* ReceiptDateFormatterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D11B81CE2530687D00E19863 /* ReceiptDateFormatterTests.swift */; };
+		D11B81D02530687D00E19863 /* ReceiptDateFormatterTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D11B81CE2530687D00E19863 /* ReceiptDateFormatterTests.swift */; };
 		D1239FFF1F6A7B5000D0421E /* AppleIncRootCertificate.cer in Resources */ = {isa = PBXBuildFile; fileRef = D19095C41F601DEA0095729B /* AppleIncRootCertificate.cer */; };
 		D123A0001F6A7CCF00D0421E /* AppleIncRootCertificate.cer in Resources */ = {isa = PBXBuildFile; fileRef = D19095C41F601DEA0095729B /* AppleIncRootCertificate.cer */; };
 		D13E5B7D20331B9B001880F0 /* DropAcceptingTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D13E5B7C20331B9B001880F0 /* DropAcceptingTextView.swift */; };
@@ -278,6 +280,7 @@
 
 /* Begin PBXFileReference section */
 		D114544521A6BDE6001BEC61 /* DeviceIdentifierTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceIdentifierTests.swift; sourceTree = "<group>"; };
+		D11B81CE2530687D00E19863 /* ReceiptDateFormatterTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ReceiptDateFormatterTests.swift; sourceTree = "<group>"; };
 		D13E5B7C20331B9B001880F0 /* DropAcceptingTextView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DropAcceptingTextView.swift; sourceTree = "<group>"; };
 		D14FA72E1F6143C400545540 /* Date+Convenience.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Date+Convenience.swift"; sourceTree = "<group>"; };
 		D14FA7311F61472400545540 /* mac_mindnode_rebought_receipt */ = {isa = PBXFileReference; lastKnownFileType = file; path = mac_mindnode_rebought_receipt; sourceTree = "<group>"; };
@@ -606,6 +609,7 @@
 				D1D6F5411F5D8A3800E86FE1 /* AppReceiptValidationTests.swift */,
 				D1AA845A1F6ABB31007F2558 /* AppReceiptPropertyValidationTests.swift */,
 				D150A0ED1F669A880026ED04 /* AppReceiptValidationInAppPurchaseTests.swift */,
+				D11B81CE2530687D00E19863 /* ReceiptDateFormatterTests.swift */,
 				D114544521A6BDE6001BEC61 /* DeviceIdentifierTests.swift */,
 				D1D6F5481F5D9B1100E86FE1 /* Tools */,
 				D1D6F5431F5D8DBC00E86FE1 /* Test Assets */,
@@ -1403,6 +1407,7 @@
 				D19095CD1F601E960095729B /* AppReceiptValidationTests.swift in Sources */,
 				D1AA845D1F6ABB59007F2558 /* AppReceiptPropertyValidationTests.swift in Sources */,
 				D150A0EF1F669A880026ED04 /* AppReceiptValidationInAppPurchaseTests.swift in Sources */,
+				D11B81D02530687D00E19863 /* ReceiptDateFormatterTests.swift in Sources */,
 				D114544721A6BDE6001BEC61 /* DeviceIdentifierTests.swift in Sources */,
 				D150A0F01F67E0990026ED04 /* Date+Convenience.swift in Sources */,
 			);
@@ -1416,6 +1421,7 @@
 				D19095CE1F601E980095729B /* AppReceiptValidationTests.swift in Sources */,
 				D1AA845C1F6ABB59007F2558 /* AppReceiptPropertyValidationTests.swift in Sources */,
 				D150A0EE1F669A880026ED04 /* AppReceiptValidationInAppPurchaseTests.swift in Sources */,
+				D11B81CF2530687D00E19863 /* ReceiptDateFormatterTests.swift in Sources */,
 				D114544621A6BDE6001BEC61 /* DeviceIdentifierTests.swift in Sources */,
 				D150A0F11F67E0990026ED04 /* Date+Convenience.swift in Sources */,
 			);

AppReceiptValidator/AppReceiptValidator/AppReceiptValidator.swift

@@ -88,16 +88,6 @@ public struct AppReceiptValidator {
         let receiptContainer = try self.extractPKCS7Container(data: receiptData)
         return try parseReceipt(pkcs7: receiptContainer, parseUnofficialParts: true)
     }
-
-    /// Uses receipt-conform representation of dates like "2017-01-01T12:00:00Z"
-    public static let asn1DateFormatter: DateFormatter = {
-        // Date formatter code from https://www.objc.io/issues/17-security/receipt-validation/#parsing-the-receipt
-        let dateFormatter = DateFormatter()
-        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
-        dateFormatter.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"
-        dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
-        return dateFormatter
-    }()
 }
 
 // MARK: - Full Validation
@@ -351,6 +341,59 @@ private extension AppReceiptValidator {
     }
 }
 
+// MARK: - ReceiptDateFormatter
+
+extension AppReceiptValidator {
+
+    /// Static formatting methods to use for string encoded date values in receipts
+    public enum ReceiptDateFormatter {
+
+        /// Uses receipt-conform representation of dates like "2017-01-01T12:00:00Z",
+        /// as a fallback, dates like "2017-01-01T12:00:00.123Z" are also parsed.
+        public static func date(from string: String) -> Date? {
+            return self.asn1DateFormatter.date(from: string) // expected
+                ?? self.fallbackDateFormatterWithMS.date(from: string) // try again with milliseconds
+        }
+
+        /// Returns receipt-conform string representation of dates like "2017-01-01T12:00:00Z",
+        /// but if the date has sub-second fractions a millisecond representation like "2017-01-01T12:00:00.123Z" is returned.
+        public static func string(from date: Date) -> String {
+            if floor(date.timeIntervalSince1970) == date.timeIntervalSince1970 {
+                // Integer seconds granularity is what we expect
+                return self.asn1DateFormatter.string(from: date)
+            } else {
+                // millis seconds granularity is what we expect
+                return self.fallbackDateFormatterWithMS.string(from: date)
+            }
+        }
+
+        /// Uses receipt-conform representation of dates like "2017-01-01T12:00:00Z"
+        static let asn1DateFormatter: DateFormatter = {
+            // Date formatter code from https://www.objc.io/issues/17-security/receipt-validation/#parsing-the-receipt
+            let dateFormatter = DateFormatter()
+            dateFormatter.locale = Locale(identifier: "en_US_POSIX")
+            dateFormatter.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'Z'"
+            dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
+            return dateFormatter
+        }()
+
+        /// Uses receipt-conform representation of dates like "2017-01-01T12:00:00.123Z"
+        ///
+        /// This is not the officially intended format, but added after hearing reports about new format adding ms https://twitter.com/depth42/status/1314179654811607041
+        private static let fallbackDateFormatterWithMS: DateFormatter = {
+            let dateFormatter = DateFormatter()
+            dateFormatter.locale = Locale(identifier: "en_US_POSIX")
+            dateFormatter.dateFormat = "yyyy'-'MM'-'dd'T'HH':'mm':'ss'.'SSS'Z'"
+            dateFormatter.timeZone = TimeZone(secondsFromGMT: 0)
+            return dateFormatter
+        }()
+    }
+
+    /// Uses receipt-conform representation of dates like "2017-01-01T12:00:00Z"
+    @available(*, deprecated, message: "Use AppReceiptValidator.ReceiptDateFormatter.string(from:) or AppReceiptValidator.ReceiptDateFormatter.date(from:) instead, to cover unexpected date formats")
+    public static let asn1DateFormatter: DateFormatter = ReceiptDateFormatter.asn1DateFormatter
+}
+
 // MARK: - Result
 
 extension AppReceiptValidator {

AppReceiptValidator/AppReceiptValidator/OpenSSL/ASN1Helpers.swift

@@ -153,7 +153,7 @@ extension ASN1Object {
     var dateValue: Date? {
         guard let string = self.stringValue else { return nil }
 
-        return AppReceiptValidator.asn1DateFormatter.date(from: string)
+        return AppReceiptValidator.ReceiptDateFormatter.date(from: string)
     }
 }
 

AppReceiptValidator/AppReceiptValidator/Receipt.swift

@@ -294,7 +294,7 @@ private struct StringFormatter {
     func format(_ date: Date?) -> String {
         guard let date = date else { return fallback }
 
-        return quoted(AppReceiptValidator.asn1DateFormatter.string(from: date))
+        return quoted(AppReceiptValidator.ReceiptDateFormatter.string(from: date))
     }
 
     func format(_ string: String?) -> String {
@@ -318,7 +318,7 @@ private func parseBase64(string: String) -> Data? {
 
 // Parses a string of type "2017-01-01T12:00:00Z"
 private func parseDate(string: String) -> Date? {
-    guard let date = AppReceiptValidator.asn1DateFormatter.date(from: string) else {
+    guard let date = AppReceiptValidator.ReceiptDateFormatter.date(from: string) else {
         assertionFailure("Date could not be parsed from string '\(string)', make sure it has a correct format, example  `2017-01-01T12:00:00Z`")
         return nil
     }

AppReceiptValidator/AppReceiptValidator/UnofficialReceipt.swift

@@ -61,7 +61,7 @@ public enum KnownUnofficialReceiptAttribute: Int32 {
     var parsingType: ParsingType {
         switch self {
         case .date1, .date2, .date3:
-            return .string
+            return .date
         case .provisioningType, .ageRating, .clientName:
             return .string
         }
@@ -115,7 +115,7 @@ extension UnofficialReceipt.Entry.Value: CustomStringConvertible {
         case .string(let value):
             return "\"\(value)\""
         case .date(let date):
-            return AppReceiptValidator.asn1DateFormatter.string(from: date)
+            return AppReceiptValidator.ReceiptDateFormatter.string(from: date)
         case .bytes(let bytes):
             if bytes.count == 2 && bytes.first == 12 && bytes.dropFirst().first == 0 {
                 return "2 bytes (12, 0)"