Fix: eager delegation causes link skipping.

Author: dblock

.rubocop_todo.yml

@@ -1,5 +1,5 @@
 # This configuration was generated by `rubocop --auto-gen-config`
-# on 2014-10-17 09:13:36 -0400 using RuboCop version 0.26.1.
+# on 2015-06-05 09:21:59 -0400 using RuboCop version 0.27.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -8,12 +8,12 @@
 # Offense count: 1
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 129
+  Max: 103
 
-# Offense count: 72
+# Offense count: 78
 # Configuration parameters: AllowURI, URISchemes.
 Metrics/LineLength:
-  Max: 140
+  Max: 142
 
 # Offense count: 3
 # Configuration parameters: CountComments.

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### 0.7.1 (Next)
 
+* [#87](https://github.com/codegram/hyperclient/pull/87): Fix: eager delegation causes link skipping - [@dblock](https://github.com/dblock).
 * Your contribution here.
 
 ### 0.7.0 (February 23, 2015)

features/api_navigation.feature

@@ -21,3 +21,8 @@ Feature: API navigation
     Given I connect to the API
     When I load a single post
     Then I should also be able to access it's embedded comments
+
+  Scenario: Navigation links
+    When I connect to the API
+    Then I should be able to navigate to next page
+    Then I should be able to navigate to next page without links

features/steps/api_navigation.rb

@@ -30,4 +30,12 @@ class Spinach::Features::ApiNavigation < Spinach::FeatureSteps
     comment = @post._embedded.comments.first
     comment._attributes.title.wont_equal nil
   end
+
+  step 'I should be able to navigate to next page' do
+    assert_equal '/posts_of_page2', api._links.next._links.posts._url
+  end
+
+  step 'I should be able to navigate to next page without links' do
+    assert_equal '/posts_of_page2', api.next.posts._url
+  end
 end

features/support/api.rb

@@ -8,6 +8,8 @@ module API
     stub_request(:any, %r{api.example.org*}).to_return(body: root_response, headers: { 'Content-Type' => 'application/hal+json' })
     stub_request(:get, 'api.example.org/posts').to_return(body: posts_response, headers: { 'Content-Type' => 'application/hal+json' })
     stub_request(:get, 'api.example.org/posts/1').to_return(body: post_response, headers: { 'Content-Type' => 'application/hal+json' })
+    stub_request(:get, 'api.example.org/page2').to_return(body: page2_response, headers: { 'Content-Type' => 'application/hal+json' })
+    stub_request(:get, 'api.example.org/page3').to_return(body: page3_response, headers: { 'Content-Type' => 'application/hal+json' })
   end
 
   def api

features/support/fixtures.rb

@@ -8,7 +8,8 @@ def root_response
               "self": { "href": "/" },
               "posts": { "href": "/posts" },
               "search": { "href": "/search{?q}", "templated": true },
-              "api:authors": { "href": "/authors" }
+              "api:authors": { "href": "/authors" },
+              "next": { "href": "/page2" }
           }
       }'
     end
@@ -39,5 +40,25 @@ def post_response
           }
       }'
     end
+
+    def page2_response
+      '{
+          "_links": {
+              "self": { "href": "/page2" },
+              "posts": { "href": "/posts_of_page2" },
+              "next": { "href": "/page3" }
+          }
+      }'
+    end
+
+    def page3_response
+      '{
+          "_links": {
+              "self": { "href": "/page3" },
+              "posts": { "href": "/posts_of_page3" },
+              "api:authors": { "href": "/authors" }
+          }
+      }'
+    end
   end
 end

lib/hyperclient/entry_point.rb

@@ -29,6 +29,7 @@ def message
   #
   class EntryPoint < Link
     extend Forwardable
+
     # Public: Delegates common methods to be used with the Faraday connection.
     def_delegators :connection, :basic_auth, :digest_auth, :token_auth, :headers, :headers=, :params, :params=
 

lib/hyperclient/link.rb

@@ -123,20 +123,25 @@ def to_s
 
     private
 
-    # Internal: Delegate the method to the API if it exists.
-    #
-    # This allows `api.posts` instead of `api.links.posts.embedded`
+    # Internal: Delegate the method further down the API if the resource cannot serve it.
     def method_missing(method, *args, &block)
-      if @key && _resource.respond_to?(@key) && (delegate = _resource.send(@key)) && delegate.respond_to?(method.to_s)
-        # named.named becomes named
-        delegate.send(method, *args, &block)
-      elsif _resource.respond_to?(method.to_s)
-        _resource.send(method, *args, &block)
+      if _resource.respond_to?(method.to_s)
+        _resource.send(method, *args, &block) || delegate_method(method, *args, &block)
       else
         super
       end
     end
 
+    # Internal: Delegate the method to the API if the resource cannot serve it.
+    #
+    # This allows `api.posts` instead of `api._links.posts.embedded.posts`
+    def delegate_method(method, *args, &block)
+      return unless @key && _resource.respond_to?(@key)
+      @delegate ||= _resource.send(@key)
+      return unless @delegate && @delegate.respond_to?(method.to_s)
+      @delegate.send(method, *args, &block)
+    end
+
     # Internal: Accessory method to allow the link respond to the
     # methods that will hit method_missing.
     def respond_to_missing?(method, _include_private = false)

test/hyperclient/link_test.rb

@@ -272,6 +272,16 @@ module Hyperclient
           resource.foos._embedded.orders.first.id.must_equal 1
           resource.foos.first.must_equal nil
         end
+
+        it 'backtracks when navigating links' do
+          resource = Resource.new({ '_links' => { 'next' => { 'href' => '/page2' } } }, entry_point)
+
+          stub_request(entry_point.connection) do |stub|
+            stub.get('http://api.example.org/page2') { [200, {}, { '_links' => { 'next' => { 'href' => 'http://api.example.org/page3' } } }] }
+          end
+
+          resource.next._links.next._url.must_equal 'http://api.example.org/page3'
+        end
       end
 
       describe 'resource' do