fix: Support validating dates on linux

Author: kylef

Sources/Claims.swift

@@ -39,12 +39,31 @@ func validateIssuer(_ payload: Payload, issuer: String?) throws {
 }
 
 func validateDate(_ payload:Payload, key:String, comparison:ComparisonResult, failure:InvalidToken, decodeError:String) throws {
-  if let timestamp = payload[key] as? TimeInterval ?? (payload[key] as? NSString)?.doubleValue as TimeInterval? {
-    let date = Date(timeIntervalSince1970: timestamp)
-    if date.compare(Date()) == comparison {
-      throw failure
-    }
-  } else if payload[key] != nil {
+  if payload[key] == nil {
+    return
+  }
+
+  guard let date = extractDate(payload: payload, key: key) else {
     throw InvalidToken.decodeError(decodeError)
   }
+
+  if date.compare(Date()) == comparison {
+    throw failure
+  }
+}
+
+fileprivate func extractDate(payload: Payload, key: String) -> Date? {
+  if let timestamp = payload[key] as? TimeInterval {
+    return Date(timeIntervalSince1970: timestamp)
+  }
+
+  if let timestamp = payload[key] as? Int {
+    return Date(timeIntervalSince1970: Double(timestamp))
+  }
+
+  if let timestampString = payload[key] as? String, let timestamp = Double(timestampString) {
+    return Date(timeIntervalSince1970: timestamp)
+  }
+
+  return nil
 }

Tests/JWTTests/JWTTests.swift

@@ -176,7 +176,7 @@ class DecodeTests: XCTestCase {
       XCTAssertEqual(payload as! [String: Int], ["iat": 1428189720])
     }
   }
-  
+
   func testIssuedAtClaimInThePastString() {
     let jwt = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOiIxNDI4MTg5NzIwIn0.M8veWtsY52oBwi7LRKzvNnzhjK0QBS8Su1r0atlns2k"
     assertSuccess(try decode(jwt, algorithm: .hs256("secret".data(using: .utf8)!))) { payload in