PageableResponse no longer enumerates all pages in response to #count.

Fixes #106

CHANGELOG.md

@@ -1,6 +1,11 @@
 Next Release (TBD)
 ------------------
 
+* Issue - Aws::PageableResponse - Calling `#count` on a pageable response
+  was triggering n API calls to get the number of response pages. Instead
+  it raises an error now, unless the wrapped data object responds to
+  count. Fixes #106.
+
 2.0.3 (2014-10-16)
 ------------------
 

aws-sdk-core/lib/aws-sdk-core/pageable_response.rb

@@ -84,6 +84,24 @@ def each_page(&block)
     end
     alias each each_page
 
+    # @api private
+    def count
+      if respond_to?(:count)
+        data.count
+      else
+        raise NotImplementedError
+      end
+    end
+
+    # @api private
+    def respond_to?(method_name, *args)
+      if method_name == :count
+        data.respond_to?(:count)
+      else
+        super
+      end
+    end
+
     private
 
     # @param [Hash] params A hash of additional request params to

aws-sdk-core/spec/aws/pageable_response_spec.rb

@@ -171,5 +171,39 @@ module Aws
       end
 
     end
+
+    describe '#count' do
+
+      it 'raises not implemented error by default' do
+        data = double('data')
+        resp = double('resp', data:data, error:nil, context:nil)
+        page = PageableResponse.new(resp, Paging::NullPager.new)
+        expect {
+          page.count
+        }.to raise_error(NotImplementedError)
+      end
+
+      it 'passes count from the raises not implemented error by default' do
+        data = double('data', count: 10)
+        resp = double('resp', data:data, error:nil, context:nil)
+        page = PageableResponse.new(resp, Paging::NullPager.new)
+        expect(page.count).to eq(10)
+      end
+
+      it 'returns false from respond_to when count not present' do
+        data = double('data')
+        resp = double('resp', data:data, error:nil, context:nil)
+        page = PageableResponse.new(resp, Paging::NullPager.new)
+        expect(page.respond_to?(:count)).to be(false)
+      end
+
+      it 'indicates it responds to count when data#count exists' do
+        data = double('data', count: 10)
+        resp = double('resp', data:data, error:nil, context:nil)
+        page = PageableResponse.new(resp, Paging::NullPager.new)
+        expect(page.respond_to?(:count))
+      end
+
+    end
   end
 end