3 files changed, 73 insertions, 7 deletions
diff --git a/lib/nickserver/dispatcher.rb b/lib/nickserver/dispatcher.rb
index 7a584e5..9968e95 100644
--- a/lib/nickserver/dispatcher.rb
+++ b/lib/nickserver/dispatcher.rb
@@ -35,10 +35,7 @@ module Nickserver
     protected
 
     def handle(request)
-      handler_chain.each do |handler|
-        response = handler.call request
-        return response if response
-      end
+      handler_chain.handle request
     rescue RuntimeError => exc
       puts "Error: #{exc}"
       puts exc.backtrace
@@ -46,13 +43,11 @@ module Nickserver
     end
 
     def handler_chain
-      [
-        RequestHandlers::InvalidEmailHandler,
+      HandlerChain.new RequestHandlers::InvalidEmailHandler,
         RequestHandlers::LocalEmailHandler,
         RequestHandlers::HkpEmailHandler,
         RequestHandlers::FingerprintHandler,
         Proc.new { Nickserver::Response.new(404, "404 Not Found\n") }
-      ]
     end
 
     def send_response(response)
diff --git a/lib/nickserver/handler_chain.rb b/lib/nickserver/handler_chain.rb
new file mode 100644
index 0000000..a0eba4d
--- /dev/null
+++ b/lib/nickserver/handler_chain.rb
@@ -0,0 +1,26 @@
+#
+# Handler Chain
+#
+# A chain of handlers that respond to call. Invoking handle(*args) on the chain
+# will call the handlers with the given args until one of them returns a result
+# that is truethy (i.e. not false or nil).
+#
+# Extracted from the dispatcher so we can also handle exceptions here in the
+# future.
+#
+
+module Nickserver
+  class HandlerChain
+
+    def initialize(*handlers)
+      @handlers = handlers
+    end
+
+    def handle(*args)
+      result = nil
+      _handled_by = @handlers.find{|h| result = h.call(*args)}
+      result
+    end
+
+  end
+end
diff --git a/test/unit/handler_chain_test.rb b/test/unit/handler_chain_test.rb
new file mode 100644
index 0000000..067f11e
--- /dev/null
+++ b/test/unit/handler_chain_test.rb
@@ -0,0 +1,45 @@
+require 'test_helper'
+require 'nickserver/handler_chain'
+
+class HandlerChainTest < Minitest::Test
+
+  def test_initialization
+    assert chain
+  end
+
+  def test_noop
+    assert_nil chain.handle
+  end
+
+  def test_triggering_handlers
+    handler_mock.expect :call, nil, [:a, :b]
+    chain handler_mock
+    chain.handle :a, :b
+    handler_mock.verify
+  end
+
+  def test_returns_handler_result
+    chain  handler_with_nil, handler_with_result
+    assert_equal :result, chain.handle
+  end
+
+
+  protected
+
+  def chain(*handlers)
+    @chain ||= Nickserver::HandlerChain.new(*handlers)
+  end
+
+  def handler_mock
+    @handler ||= Minitest::Mock.new
+  end
+
+  def handler_with_nil
+    Proc.new {}
+  end
+
+  def handler_with_result
+    Proc.new { :result }
+  end
+
+end