fix: #3 handle domains without A-record

If a domain only has an mx record but no A record it
will trigger a ConnectionError when attempting the
nicknym key lookup.

We need to detect and handle this in the http adapter
already because once the exception is handled by Celluloid
our actor will be terminated.

So now we allow for handing a rescue option to the
adapter with a string that is checked for inclusion in
the error message. If the string is found the exception
will be caught and the adapter returns nil.

We only make use of this when checking the availability
of nicknym so far. That should be the only http request
going out.

2 files changed, 17 insertions, 1 deletions

diff --git a/lib/nickserver/adapters/http.rb b/lib/nickserver/adapters/http.rb
index 636aceb..eb77cc6 100644
--- a/lib/nickserver/adapters/http.rb
+++ b/lib/nickserver/adapters/http.rb
@@ -2,6 +2,19 @@ require 'nickserver/adapters'
 require 'nickserver/config'
 require 'http'
 
+# Nickserver::Adapters::Http
+#
+# Basic http adapter with ssl and minimal error handling.
+# Only implemented get requests so far.
+#
+# Error Handling:
+#
+# Pass a string as the 'rescue' option. If a ConnectionError occures
+# which includes the string passed it will be rescued and the request
+# will return nil. This allows handling the error inside the adapter so
+# that for the derived CelluloidHttp Adapter the actor does not get
+# killed.
+
 module Nickserver::Adapters
   class Http
 
@@ -9,6 +22,8 @@ module Nickserver::Adapters
       url = HTTP::URI.parse url.to_s
       response = get_with_auth url, params: options[:query]
       return response.code, response.to_s
+    rescue HTTP::ConnectionError => e
+      raise unless options[:rescue] && e.to_s.include?(options[:rescue])
     end
 
     protected
diff --git a/lib/nickserver/nicknym/source.rb b/lib/nickserver/nicknym/source.rb
index 96945cb..f49547e 100644
--- a/lib/nickserver/nicknym/source.rb
+++ b/lib/nickserver/nicknym/source.rb
@@ -8,7 +8,8 @@ module Nickserver
       PORT = 6425
 
       def available_for?(domain)
-        status, body = adapter.get "https://#{domain}/provider.json"
+        status, body = adapter.get "https://#{domain}/provider.json",
+          rescue: 'failed to connect: getaddrinfo'
         status == 200 && provider_with_mx?(body)
       end