adding check for devices on network (#33)

Sources/SublimationBonjour/NWTXTRecord.swift

@@ -37,5 +37,9 @@
       }
       return value
     }
+
+    internal func getKeys() -> any Sequence<String> {
+      self.dictionary.keys
+    }
   }
 #endif

Sources/SublimationBonjour/SublimationKey.swift

@@ -53,6 +53,24 @@ extension SublimationKey {
     }
     return [prefix, value.description].joined(separator: "_")
   }
+
+  internal static func isValid(_ string: String) -> Bool {
+    if SublimationKeyValues(rawValue: string) != nil {
+      return true
+    }
+    if string.hasPrefix(SublimationKeyValues.address.rawValue),
+       string.count > SublimationKeyValues.address.rawValue.count + 1 {
+      let indexString = string.suffix(
+        from: string.index(
+          string.startIndex,
+          offsetBy: SublimationKeyValues.address.rawValue.count + 1
+        )
+      )
+
+      return (Int(indexString) ?? .min) >= 0
+    }
+    return false
+  }
 }
 
 extension SublimationKeyValues {

Sources/SublimationBonjour/TXTRecord.swift

@@ -33,6 +33,7 @@ internal protocol TXTRecord {
   var count: Int { get }
   init(_ dictionary: [String: String])
   func getStringEntry(for key: String) -> String?
+  func getKeys() -> any Sequence<String>
 }
 
 extension TXTRecord {
@@ -89,6 +90,9 @@ extension TXTRecord {
       defaultPort: defaultPort,
       defaultTLS: defaultTLS
     )
+    guard let configuration else {
+      return []
+    }
     logger?.log { $0.debug("Parsing \(configuration.count) Addresses") }
     return (0 ..< configuration.count).compactMap { index -> URL? in
       let host: String? = self.getEntry(for: .address(index)).value
@@ -117,7 +121,7 @@ extension TXTRecord {
     logger: LoggingActor?,
     defaultPort: Int,
     defaultTLS: Bool
-  ) -> URL.Configuration {
+  ) -> URL.Configuration? {
     var offset = 0
 
     let portEntry = self.getEntry(for: .port, of: Int.self)
@@ -138,6 +142,14 @@ extension TXTRecord {
       logger?.log { $0.warning("Port Entry is invalid: \(invalidTLSEntryString)") }
     }
 
+    let isValid = self.getKeys().allSatisfy { key in
+      SublimationKey.isValid(key)
+    }
+
+    guard isValid else {
+      return nil
+    }
+
     return self.urlConfiguration(at: offset, port: port, isTLS: isTLS, logger: logger)
   }
 }

Tests/SublimationBonjourTests/MockTXTRecord.swift

@@ -32,6 +32,10 @@ import Foundation
 import XCTest
 
 internal struct MockTXTRecord: TXTRecord {
+  func getKeys() -> any Sequence<String> {
+    dictionary.keys
+  }
+
   internal let dictionary: [String: String]
 
   internal var count: Int {

Tests/SublimationBonjourTests/TXTRecordTests.swift

@@ -32,6 +32,13 @@ import Foundation
 import XCTest
 
 internal class TXTRecordTests: XCTestCase {
+  internal func testBadRecord() {
+    let record = MockTXTRecord(["Serial Number": UUID().uuidString])
+    let urls = record.urls(defaultPort: 0, defaultTLS: false, logger: nil)
+
+    XCTAssert(urls.isEmpty)
+  }
+
   internal func testInit() {
     let expectation = expectation(description: "Filter")
 
@@ -111,4 +118,3 @@ internal class TXTRecordTests: XCTestCase {
     XCTAssertEqual(urls, expectedURLs)
   }
 }
-