Respect hash_access setting when using expose_nil: false option (#359)

* Fix Lint/ElseLayout Rubocop warning

* Document Entity.hash_access=

* Move Delegator option acceptance check to Delegator::Base

* Pass hash_access to Delegator when it's both present and accepted

* Update CHANGELOG

Author: magni-

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 #### Fixes
 
+* [#359](https://github.com/ruby-grape/grape-entity/pull/359): Respect `hash_access` setting when using `expose_nil: false` option - [@magni-](https://github.com/magni-).
 * Your contribution here.
 
 

README.md

@@ -111,6 +111,20 @@ The field lookup takes several steps
 * next try `object.fetch(exposure)`
 * last raise an Exception
 
+`exposure` is a Symbol by default. If `object` is a Hash with stringified keys, you can set the hash accessor at the entity-class level to properly expose its members:
+
+```ruby
+class Status < GrapeEntity
+  self.hash_access = :to_s
+
+  expose :code
+  expose :message
+end
+
+Status.represent({ 'code' => 418, 'message' => "I'm a teapot" }).as_json
+#=> { code: 418, message: "I'm a teapot" }
+```
+
 #### Exposing with a Presenter
 
 Don't derive your model classes from `Grape::Entity`, expose them using a presenter.

lib/grape_entity/delegator.rb

@@ -11,10 +11,14 @@ class Entity
     module Delegator
       def self.new(object)
         delegator_klass =
-          if object.is_a?(Hash) then HashObject
-          elsif defined?(OpenStruct) && object.is_a?(OpenStruct) then OpenStructObject
-          elsif object.respond_to?(:fetch, true) then FetchableObject
-          else PlainObject
+          if object.is_a?(Hash)
+            HashObject
+          elsif defined?(OpenStruct) && object.is_a?(OpenStruct)
+            OpenStructObject
+          elsif object.respond_to?(:fetch, true)
+            FetchableObject
+          else
+            PlainObject
           end
 
         delegator_klass.new(object)

lib/grape_entity/delegator/base.rb

@@ -13,6 +13,11 @@ def initialize(object)
         def delegatable?(_attribute)
           true
         end
+
+        def accepts_options?
+          # Why not `arity > 1`? It might be negative https://ruby-doc.org/core-2.6.6/Method.html#method-i-arity
+          method(:delegate).arity != 1
+        end
       end
     end
   end

lib/grape_entity/entity.rb

@@ -481,9 +481,6 @@ def initialize(object, options = {})
       @object = object
       @options = options.is_a?(Options) ? options : Options.new(options)
       @delegator = Delegator.new(object)
-
-      # Why not `arity > 1`? It might be negative https://ruby-doc.org/core-2.6.6/Method.html#method-i-arity
-      @delegator_accepts_opts = @delegator.method(:delegate).arity != 1
     end
 
     def root_exposures
@@ -541,7 +538,7 @@ def value_for(key, options = Options.new)
     def delegate_attribute(attribute)
       if is_defined_in_entity?(attribute)
         send(attribute)
-      elsif @delegator_accepts_opts
+      elsif delegator.accepts_options?
         delegator.delegate(attribute, **self.class.delegation_opts)
       else
         delegator.delegate(attribute)

lib/grape_entity/exposure.rb

@@ -56,7 +56,12 @@ def expose_nil_condition(attribute, options)
           Condition.new_unless(
             proc do |object, _options|
               if options[:proc].nil?
-                Delegator.new(object).delegate(attribute).nil?
+                delegator = Delegator.new(object)
+                if is_a?(Grape::Entity) && delegator.accepts_options?
+                  delegator.delegate(attribute, **self.class.delegation_opts).nil?
+                else
+                  delegator.delegate(attribute).nil?
+                end
               else
                 exec_with_object(options, &options[:proc]).nil?
               end

spec/grape_entity/hash_spec.rb

@@ -17,7 +17,7 @@ class AddressWithString < Grape::Entity
         expose :post, if: :full
         expose :city
         expose :street
-        expose :house
+        expose :house, expose_nil: false
       end
 
       class Company < Grape::Entity
@@ -62,9 +62,23 @@ class CompanyWithString < Grape::Entity
       }
     }
 
+    company_without_house_with_string = {
+      'full_name' => 'full_name',
+      'name' => 'name',
+      'address' => {
+        'post' => '123456',
+        'city' => 'city',
+        'street' => 'street',
+        'something_else' => 'something_else'
+      }
+    }
+
     expect(EntitySpec::CompanyWithString.represent(company_with_string).serializable_hash).to eq \
       company.slice(:name).merge(address: company[:address].slice(:city, :street, :house))
 
+    expect(EntitySpec::CompanyWithString.represent(company_without_house_with_string).serializable_hash).to eq \
+      company.slice(:name).merge(address: company[:address].slice(:city, :street))
+
     expect(EntitySpec::CompanyWithString.represent(company_with_string, full: true).serializable_hash).to eq \
       company.slice(:full_name, :name).merge(address: company[:address].slice(:city, :street, :house))