Support global exclude links configuration

Closes gh-1256

lib/jsonapi/configuration.rb

@@ -33,7 +33,8 @@ class Configuration
                 :resource_cache,
                 :default_resource_cache_field,
                 :resource_cache_digest_function,
-                :resource_cache_usage_report_function
+                :resource_cache_usage_report_function,
+                :default_exclude_links
 
     def initialize
       #:underscored_key, :camelized_key, :dasherized_key, or custom
@@ -134,6 +135,12 @@ def initialize
       # Optionally provide a callable which JSONAPI will call with information about cache
       # performance. Should accept three arguments: resource name, hits count, misses count.
       self.resource_cache_usage_report_function = nil
+
+      # Global configuration for links exclusion
+      # Controls whether to generate links like `self`, `related` with all the resources
+      # and relationships. Accepts either `:default`, `:none`, or array containing the
+      # specific default links to exclude, which may be `:self` and `:related`.
+      self.default_exclude_links = :none
     end
 
     def cache_formatters=(bool)
@@ -249,6 +256,8 @@ def default_processor_klass=(default_processor_klass)
     attr_writer :resource_cache_digest_function
 
     attr_writer :resource_cache_usage_report_function
+
+    attr_writer :default_exclude_links
   end
 
   class << self

lib/jsonapi/relationship.rb

@@ -16,11 +16,10 @@ def initialize(name, options = {})
       @polymorphic = options.fetch(:polymorphic, false) == true
       @always_include_linkage_data = options.fetch(:always_include_linkage_data, false) == true
       @eager_load_on_include = options.fetch(:eager_load_on_include, true) == true
-
       @_routed = false
       @_warned_missing_route = false
 
-      exclude_links(options.fetch(:exclude_links, :none))
+      exclude_links(options.fetch(:exclude_links, JSONAPI.configuration.default_exclude_links))
     end
 
     alias_method :polymorphic?, :polymorphic

lib/jsonapi/resource.rb

@@ -1069,6 +1069,18 @@ def mutable?
       end
 
       def exclude_links(exclude)
+        _resolve_exclude_links(exclude)
+      end
+
+      def _exclude_links
+        @_exclude_links ||= _resolve_exclude_links(JSONAPI.configuration.default_exclude_links)
+      end
+
+      def exclude_link?(link)
+        _exclude_links.include?(link.to_sym)
+      end
+
+      def _resolve_exclude_links(exclude)
         case exclude
           when :default, "default"
             @_exclude_links = [:self]
@@ -1081,14 +1093,6 @@ def exclude_links(exclude)
         end
       end
 
-      def _exclude_links
-        @_exclude_links ||= []
-      end
-
-      def exclude_link?(link)
-        _exclude_links.include?(link.to_sym)
-      end
-
       def caching(val = true)
         @caching = val
       end

test/unit/resource/relationship_test.rb

@@ -9,6 +9,88 @@ def test_polymorphic_type
     assert_equal(relationship.polymorphic_type, "imageable_type")
   end
 
+  def test_global_exclude_links_configuration_on_relationship
+    JSONAPI.configuration.default_exclude_links = :none
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = :default
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [:self, :related], relationship._exclude_links
+    assert relationship.exclude_link?(:self)
+    assert relationship.exclude_link?("self")
+    assert relationship.exclude_link?(:related)
+    assert relationship.exclude_link?("related")
+
+    JSONAPI.configuration.default_exclude_links = "none"
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = "default"
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [:self, :related], relationship._exclude_links
+    assert relationship.exclude_link?(:self)
+    assert relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = :none
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = [:self]
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [:self], relationship._exclude_links
+    assert relationship.exclude_link?(:self)
+    assert relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = :none
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = ["self", :related]
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [:self, :related], relationship._exclude_links
+    assert relationship.exclude_link?(:self)
+    assert relationship.exclude_link?("self")
+
+    JSONAPI.configuration.default_exclude_links = []
+    relationship = JSONAPI::Relationship::ToOne.new "foo"
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+
+    assert_raises do
+      JSONAPI.configuration.default_exclude_links = :self
+      JSONAPI::Relationship::ToOne.new "foo"
+    end
+
+    # Test if the relationships will override the the global configuration
+    JSONAPI.configuration.default_exclude_links = :default
+    relationship = JSONAPI::Relationship::ToOne.new "foo", exclude_links: :none
+    assert_equal [], relationship._exclude_links
+    refute relationship.exclude_link?(:self)
+    refute relationship.exclude_link?("self")
+    refute relationship.exclude_link?(:related)
+    refute relationship.exclude_link?("related")
+
+    JSONAPI.configuration.default_exclude_links = :default
+    relationship = JSONAPI::Relationship::ToOne.new "foo", exclude_links: [:self]
+    assert_equal [:self], relationship._exclude_links
+    refute relationship.exclude_link?(:related)
+    refute relationship.exclude_link?("related")
+    assert relationship.exclude_link?(:self)
+    assert relationship.exclude_link?("self")
+  ensure
+    JSONAPI.configuration.default_exclude_links = :none
+  end
+
   def test_exclude_links_on_relationship
     relationship = JSONAPI::Relationship::ToOne.new "foo", exclude_links: :none
     assert_equal [], relationship._exclude_links