Merge pull request #211 from atsign-foundation/jeremy-devicename-fix1

fix: sshnp exit if atSign DNE, sshnpd wait for atSign to exist

bin/sshnpd.dart

@@ -145,6 +145,12 @@ Future<void> _main(List<String> args) async {
 
   atClient = AtClientManager.getInstance().atClient;
 
+  // check if sshnp atSign exists
+  while(!(await atSignIsActivated(atClient, managerAtsign))) {
+    await Future.delayed(Duration(seconds: 5));
+    logger.warning('Waiting for $managerAtsign to be activated...');
+  }
+
   NotificationService notificationService = atClient.notificationService;
 
   if (results['username']) {

lib/sshnp.dart

@@ -177,6 +177,10 @@ class SSHNP {
       throw StateError('Cannot init() - already initialized');
     }
 
+    if(!(await atSignIsActivated(atClient, sshnpdAtSign))) {
+        throw ('sshnpd atSign $sshnpdAtSign is not activated.');
+    }
+
     logger.info('Subscribing to notifications on $sessionId.$nameSpace@');
     // Start listening for response notifications from sshnpd
     atClient.notificationService

lib/sshnp_utils.dart

@@ -1,5 +1,7 @@
 import 'dart:io';
 
+import 'package:at_client/at_client.dart';
+
 /// Get the home directory or null if unknown.
 String? getHomeDirectory({bool throwIfNull = false}) {
   String? homeDir;
@@ -62,3 +64,30 @@ String getDefaultSshDirectory(String homeDirectory) {
 return '$homeDirectory/.ssh/'
     .replaceAll('/', Platform.pathSeparator);
 }
+
+/// Checks if the provided atSign's atServer has been properly activated with a public RSA key.
+/// `atClient` must be authenticated
+/// `atSign` is the atSign to check
+/// Returns `true`, if the atSign's cloud secondary server has an existing `public:publickey@` in their server, 
+/// Returns `false`, if the atSign's cloud secondary *exists*, but does not have an existing `public:publickey@`
+/// Throws [AtClientException] if the cloud secondary is invalid or not reachable
+Future<bool> atSignIsActivated(final AtClient atClient, String atSign) async {
+  final Metadata metadata = Metadata()
+    ..isPublic = true
+    ..namespaceAware = false;
+
+  final AtKey publicKey = AtKey()
+    ..sharedBy = atSign
+    ..key = 'publickey'
+    ..metadata = metadata;
+
+  try {
+    await atClient.get(publicKey);
+    return true;
+  } catch (e) {
+    if(e is AtKeyNotFoundException || (e is AtClientException && e.message.contains("public:publickey") && e.message.contains("does not exist in keystore"))) {
+      return false;
+    }
+    rethrow;
+  }
+}