Catches closed connections before an exec is attempted

lib/lan_connection.js

@@ -37,6 +37,11 @@ LAN.Connection.prototype.exec = function(command) {
   var self = this;
   return new Promise(function(resolve, reject) {
 
+    // Ensure this connection hasn't been closed
+    if (self.closed) {
+      return reject(new Error('Remote SSH connection has already been closed'));
+    }
+
     // Execute the command
     if (!Array.isArray(command)) {
       return reject(new Error('Command to execute must be an array of args.'));
@@ -87,6 +92,9 @@ LAN.Connection.prototype.open = function() {
       // Reject with error
       resolve(self);
     }).connect(self.auth);
+    self.ssh.once('close', function() {
+      self.closed = true;
+    });
   });
 };