From bbb73bc99e9a8ebd7d588d3cff129bb84abb7a2c Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 16:11:45 +0200
Subject: [PATCH 1/6] Adds separate configs for attributes and parameters

---
 CHANGELOG.md                                |  30 ++
 Gemfile.lock                                |   2 +-
 lib/rest_easy/conventions.rb                |   2 +
 lib/rest_easy/resource.rb                   |  44 ++-
 lib/rest_easy/settings.rb                   |   7 +-
 lib/rest_easy/version.rb                    |   2 +-
 spec/rest_easy/resource/conversions_spec.rb | 339 ++++++++++++++++++++
 spec/rest_easy/resource_spec.rb             | 133 ++++++++
 8 files changed, 548 insertions(+), 11 deletions(-)
 create mode 100644 CHANGELOG.md
 create mode 100644 spec/rest_easy/resource/conversions_spec.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..002cd97
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,30 @@
+# Changelog
+
+## [1.1.0] - 2026-03-25
+
+### Added
+
+- **`conversions` configuration** with independent `query_parameters` and `json_attributes` sub-keys. This allows APIs that use different naming conventions for query parameters vs JSON body attributes to be configured correctly:
+
+  ```ruby
+  module MyAPI
+    extend RestEasy
+
+    configure do
+      conversions.json_attributes = :camelCase
+      conversions.query_parameters = :PascalCase
+    end
+  end
+  ```
+
+- **Automatic query parameter key transformation.** `Resource.get` now transforms parameter keys according to the `query_parameters` convention before sending the request. This removes the need for manual `transform_keys` calls in consuming gems.
+
+- `conversions` can be overridden per Resource class, with inheritance falling back to the parent API module configuration.
+
+### Deprecated
+
+- **`attribute_convention`** is deprecated in favour of `conversions.json_attributes`. The old setting continues to work and is respected as a fallback, but emits a deprecation warning when used at the Resource level. Module-level `attribute_convention` is silently supported for backwards compatibility.
+
+## [1.0.0]
+
+Initial release.
diff --git a/Gemfile.lock b/Gemfile.lock
index 7ced8de..25c3bda 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    rest-easy (0.1.0)
+    rest-easy (1.1.0)
       dry-configurable (~> 0.14)
       dry-inflector (~> 0.2.1)
       dry-types (~> 1.2)
diff --git a/lib/rest_easy/conventions.rb b/lib/rest_easy/conventions.rb
index f0b3307..13bea6d 100644
--- a/lib/rest_easy/conventions.rb
+++ b/lib/rest_easy/conventions.rb
@@ -56,6 +56,8 @@ def serialise(model_name)
       snake_case: SnakeCase.new
     }.freeze
 
+    ConventionPair = Struct.new(:query_parameters, :json_attributes, keyword_init: true)
+
     def self.resolve(convention)
       case convention
       when Symbol
diff --git a/lib/rest_easy/resource.rb b/lib/rest_easy/resource.rb
index 8a759db..41c135d 100644
--- a/lib/rest_easy/resource.rb
+++ b/lib/rest_easy/resource.rb
@@ -9,6 +9,11 @@ class Resource
     setting :path
     setting :debug, default: false
 
+    setting :conversions do
+      setting :query_parameters  # nil default — falls back to parent module
+      setting :json_attributes   # nil default — falls back to parent module
+    end
+
     # ── Types ─────────────────────────────────────────────────────────────
     # Include Types so the full Dry::Types vocabulary (Strict::String,
     # Coercible::Integer, Params::Date, etc.) is available without prefix.
@@ -143,16 +148,35 @@ def metadata(**kwargs)
         end
       end
 
-      # -- attribute_convention ------------------------------------------
+      # -- conversions ---------------------------------------------------
+
+      def resolved_conversions
+        @resolved_conversions ||= begin
+          qp = config.conversions.query_parameters ||
+               parent&.config&.conversions&.query_parameters ||
+               :snake_case
+
+          ja = config.conversions.json_attributes ||
+               parent&.config&.conversions&.json_attributes ||
+               parent&.config&.attribute_convention || # BC: old setting as fallback
+               :snake_case
+
+          Conventions::ConventionPair.new(
+            query_parameters: Conventions.resolve(qp),
+            json_attributes: Conventions.resolve(ja)
+          )
+        end
+      end
+
+      # -- attribute_convention (deprecated) -------------------------------
 
       def attribute_convention(value = nil)
         if value
-          @attribute_convention = Conventions.resolve(value)
-        else
-          @attribute_convention ||
-            (superclass.respond_to?(:attribute_convention) ? superclass.attribute_convention : nil) ||
-            Conventions.resolve(parent&.config&.attribute_convention || :PascalCase)
+          warn "RestEasy: attribute_convention is deprecated, use `configure { conversions.json_attributes = #{value.inspect} }` instead"
+          config.conversions.json_attributes = value
+          @resolved_conversions = nil # bust memoization
         end
+        resolved_conversions.json_attributes
       end
 
       private
@@ -191,7 +215,7 @@ def attr(name_or_mapping, *args, &block)
           attribute_api_name = name_or_mapping[1].to_s
         else
           attribute_model_name = name_or_mapping.to_sym
-          attribute_api_name = attribute_convention.serialise(attribute_model_name)
+          attribute_api_name = resolved_conversions.json_attributes.serialise(attribute_model_name)
         end
 
         # Extract type (non-Symbol), flags (Symbols), and optional mapper object
@@ -459,6 +483,10 @@ def delete(id)
       # HTTP primitives — delegate to the parent API module's connection
 
       def get(path:, params: {}, headers: {})
+        if params.any?
+          conv = resolved_conversions.query_parameters
+          params = params.transform_keys { |k| conv.serialise(k) }
+        end
         parent.get(path:, params:, headers:)
       end
 
@@ -578,7 +606,7 @@ def serialise
           serialised = attr_def.serialise_value(value)
           if serialised.is_a?(::Array)
             # Array return: zip with source field API names
-            convention = klass.attribute_convention
+            convention = klass.resolved_conversions.json_attributes
             attr_def.source_fields.zip(serialised).each do |field_name, field_value|
               api_key = convention.serialise(field_name)
               result[api_key] = field_value
diff --git a/lib/rest_easy/settings.rb b/lib/rest_easy/settings.rb
index 56d55ea..d261bb1 100644
--- a/lib/rest_easy/settings.rb
+++ b/lib/rest_easy/settings.rb
@@ -9,6 +9,11 @@ class Settings
     setting :base_url, default: "https://example.com", reader: true
     setting :max_retries, default: 3, reader: true
     setting :authentication, default: Auth::Null.new, reader: true
-    setting :attribute_convention, default: :PascalCase, reader: true
+    setting :attribute_convention, default: :PascalCase, reader: true # deprecated, kept for BC
+
+    setting :conversions do
+      setting :query_parameters, reader: true  # nil default — :snake_case resolved in Resource
+      setting :json_attributes, reader: true   # nil default — :snake_case resolved in Resource
+    end
   end
 end
diff --git a/lib/rest_easy/version.rb b/lib/rest_easy/version.rb
index 61fc7c2..070d118 100644
--- a/lib/rest_easy/version.rb
+++ b/lib/rest_easy/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module RestEasy
-  VERSION = "1.0.0"
+  VERSION = "1.1.0"
 end
diff --git a/spec/rest_easy/resource/conversions_spec.rb b/spec/rest_easy/resource/conversions_spec.rb
new file mode 100644
index 0000000..e135e80
--- /dev/null
+++ b/spec/rest_easy/resource/conversions_spec.rb
@@ -0,0 +1,339 @@
+# frozen_string_literal: true
+
+RSpec.describe "Resource conversions" do
+  # Helper to set up a Faraday test adapter with stubs
+  def setup_test_connection(api_module, &block)
+    stubs = Faraday::Adapter::Test::Stubs.new(&block)
+    api_module.instance_variable_set(:@faraday_connection, nil)
+    api_module.connection do |f|
+      f.request :json
+      f.response :json, content_type: /\bjson$/
+      f.adapter :test, stubs
+    end
+    stubs
+  end
+
+  # ── Module-level configuration ──────────────────────────────────────
+
+  describe "module-level conversions" do
+    before(:all) do
+      module ConvTestApi
+        extend RestEasy
+
+        configure do
+          conversions.json_attributes = :PascalCase
+          conversions.query_parameters = :camelCase
+        end
+      end
+
+      class ConvTestApi::Invoice < RestEasy::Resource
+        configure { path "invoices" }
+
+        key :document_number, Integer, :read_only
+        attr :customer_name, String
+      end
+    end
+
+    after(:all) do
+      Object.send(:remove_const, :ConvTestApi)
+    end
+
+    it "resolves json_attributes from module config" do
+      conv = ConvTestApi::Invoice.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+    end
+
+    it "resolves query_parameters from module config" do
+      conv = ConvTestApi::Invoice.resolved_conversions
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::CamelCase)
+    end
+
+    it "parses API data using json_attributes convention" do
+      instance = ConvTestApi::Invoice.parse({
+        "DocumentNumber" => 1,
+        "CustomerName" => "Acme"
+      })
+
+      expect(instance.document_number).to eq(1)
+      expect(instance.customer_name).to eq("Acme")
+    end
+
+    it "serialises using json_attributes convention" do
+      instance = ConvTestApi::Invoice.parse({
+        "DocumentNumber" => 1,
+        "CustomerName" => "Acme"
+      })
+      serialised = instance.serialise
+
+      # DocumentNumber is :read_only, so excluded from serialise
+      expect(serialised).to have_key("CustomerName")
+      expect(serialised["CustomerName"]).to eq("Acme")
+    end
+
+    it "transforms query parameter keys using query_parameters convention" do
+      captured_params = nil
+
+      setup_test_connection(ConvTestApi) do |stub|
+        stub.get("/invoices") do |env|
+          captured_params = env.params
+          [200, { "Content-Type" => "application/json" },
+           '[{"DocumentNumber": 1, "CustomerName": "Test"}]']
+        end
+      end
+
+      ConvTestApi::Invoice.get(
+        path: "invoices",
+        params: { customer_name: "Test", sort_order: "asc" }
+      )
+
+      expect(captured_params).to include("customerName" => "Test", "sortOrder" => "asc")
+    end
+  end
+
+  # ── Resource-level override ─────────────────────────────────────────
+
+  describe "resource-level override" do
+    before(:all) do
+      module ResOverrideApi
+        extend RestEasy
+
+        configure do
+          conversions.json_attributes = :camelCase
+          conversions.query_parameters = :camelCase
+        end
+      end
+
+      class ResOverrideApi::Base < RestEasy::Resource
+      end
+
+      class ResOverrideApi::Standard < ResOverrideApi::Base
+        attr :item_name, String
+      end
+
+      class ResOverrideApi::Custom < ResOverrideApi::Base
+        configure do
+          conversions.json_attributes = :PascalCase
+          conversions.query_parameters = :PascalCase
+        end
+
+        attr :item_name, String
+      end
+    end
+
+    after(:all) do
+      Object.send(:remove_const, :ResOverrideApi)
+    end
+
+    it "inherits module-level convention when not overridden" do
+      conv = ResOverrideApi::Standard.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::CamelCase)
+    end
+
+    it "uses resource-level convention when overridden" do
+      conv = ResOverrideApi::Custom.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+    end
+
+    it "parses with inherited convention" do
+      instance = ResOverrideApi::Standard.parse({ "itemName" => "Widget" })
+      expect(instance.item_name).to eq("Widget")
+    end
+
+    it "parses with overridden convention" do
+      instance = ResOverrideApi::Custom.parse({ "ItemName" => "Widget" })
+      expect(instance.item_name).to eq("Widget")
+    end
+
+    it "does not affect sibling resources" do
+      standard_conv = ResOverrideApi::Standard.resolved_conversions
+      custom_conv = ResOverrideApi::Custom.resolved_conversions
+
+      expect(standard_conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+      expect(custom_conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+    end
+  end
+
+  # ── Partial override (one key only) ─────────────────────────────────
+
+  describe "partial override" do
+    before(:all) do
+      module PartialApi
+        extend RestEasy
+
+        configure do
+          conversions.json_attributes = :camelCase
+          conversions.query_parameters = :camelCase
+        end
+      end
+
+      class PartialApi::Resource < RestEasy::Resource
+        configure do
+          conversions.query_parameters = :PascalCase
+          # json_attributes not set — inherits from module
+        end
+
+        attr :item_name, String
+      end
+    end
+
+    after(:all) do
+      Object.send(:remove_const, :PartialApi)
+    end
+
+    it "uses overridden query_parameters" do
+      conv = PartialApi::Resource.resolved_conversions
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+    end
+
+    it "inherits json_attributes from module" do
+      conv = PartialApi::Resource.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+    end
+  end
+
+  # ── Independent conventions ─────────────────────────────────────────
+
+  describe "independent query_parameters and json_attributes" do
+    before(:all) do
+      module MixedApi
+        extend RestEasy
+
+        configure do
+          conversions.json_attributes = :camelCase
+          conversions.query_parameters = :PascalCase
+        end
+      end
+
+      class MixedApi::Item < RestEasy::Resource
+        configure { path "items" }
+        attr :item_name, String
+      end
+    end
+
+    after(:all) do
+      Object.send(:remove_const, :MixedApi)
+    end
+
+    it "uses different conventions for attributes and parameters" do
+      conv = MixedApi::Item.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+    end
+
+    it "serialises attributes as camelCase" do
+      instance = MixedApi::Item.parse({ "itemName" => "Widget" })
+      serialised = instance.serialise
+      expect(serialised).to have_key("itemName")
+    end
+
+    it "transforms query params as PascalCase" do
+      captured_params = nil
+
+      setup_test_connection(MixedApi) do |stub|
+        stub.get("/items") do |env|
+          captured_params = env.params
+          [200, { "Content-Type" => "application/json" },
+           '[{"itemName": "Widget"}]']
+        end
+      end
+
+      MixedApi::Item.get(path: "items", params: { item_name: "Widget" })
+
+      expect(captured_params).to include("ItemName" => "Widget")
+    end
+  end
+
+  # ── Backwards compatibility ─────────────────────────────────────────
+
+  describe "backwards compatibility" do
+    describe "module-level attribute_convention" do
+      before(:all) do
+        module BCModuleApi
+          extend RestEasy
+
+          configure do |config|
+            config.attribute_convention = :PascalCase
+          end
+        end
+
+        class BCModuleApi::Invoice < RestEasy::Resource
+          attr :customer_name, String
+        end
+      end
+
+      after(:all) do
+        Object.send(:remove_const, :BCModuleApi)
+      end
+
+      it "resolves json_attributes from old attribute_convention setting" do
+        conv = BCModuleApi::Invoice.resolved_conversions
+        expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      end
+
+      it "defaults query_parameters to snake_case" do
+        conv = BCModuleApi::Invoice.resolved_conversions
+        expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
+      end
+
+      it "parses with the old convention" do
+        instance = BCModuleApi::Invoice.parse({ "CustomerName" => "Acme" })
+        expect(instance.customer_name).to eq("Acme")
+      end
+    end
+
+    describe "resource-level attribute_convention" do
+      it "sets json_attributes and emits a deprecation warning" do
+        resource_class = Class.new(RestEasy::Resource)
+
+        expect {
+          resource_class.attribute_convention :camelCase
+        }.to output(/deprecated/).to_stderr
+
+        expect(resource_class.resolved_conversions.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+      end
+
+      it "still works as a getter" do
+        resource_class = Class.new(RestEasy::Resource) do
+          configure { conversions.json_attributes = :PascalCase }
+          attr :item_name, String
+        end
+
+        # Suppress deprecation warning — we're testing the getter path
+        expect(resource_class.attribute_convention).to be_a(RestEasy::Conventions::PascalCase)
+      end
+    end
+  end
+
+  # ── Default resolution ──────────────────────────────────────────────
+
+  describe "default resolution" do
+    before(:all) do
+      module DefaultApi
+        extend RestEasy
+        # No conversions or attribute_convention set
+      end
+
+      class DefaultApi::Thing < RestEasy::Resource
+        attr :my_field, String
+      end
+    end
+
+    after(:all) do
+      Object.send(:remove_const, :DefaultApi)
+    end
+
+    it "falls back to attribute_convention default for json_attributes" do
+      # The old attribute_convention defaults to :PascalCase on Settings,
+      # so json_attributes picks that up via the BC fallback
+      conv = DefaultApi::Thing.resolved_conversions
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+    end
+
+    it "defaults query_parameters to snake_case" do
+      conv = DefaultApi::Thing.resolved_conversions
+      expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
+    end
+  end
+end
diff --git a/spec/rest_easy/resource_spec.rb b/spec/rest_easy/resource_spec.rb
index 7f46c70..40ee892 100644
--- a/spec/rest_easy/resource_spec.rb
+++ b/spec/rest_easy/resource_spec.rb
@@ -25,6 +25,8 @@ module TestApi
     describe "path" do
       it "sets the endpoint path via configure" do
         resource = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           configure do
             path "invoices"
           end
@@ -41,6 +43,8 @@ module TestApi
   describe "metadata" do
     it "sets default meta values on parsed instances" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         metadata partial: true
       end
@@ -51,6 +55,8 @@ module TestApi
 
     it "sets default meta values on stubbed instances" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         metadata partial: true
       end
@@ -61,6 +67,8 @@ module TestApi
 
     it "preserves defaults through update" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         metadata partial: true
       end
@@ -72,6 +80,8 @@ module TestApi
 
     it "allows instance-level override of defaults" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         metadata partial: true
       end
@@ -83,6 +93,8 @@ module TestApi
 
     it "inherits metadata from parent resource" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         metadata partial: true
       end
 
@@ -98,6 +110,8 @@ module TestApi
 
     it "returns empty hash when no metadata defined" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
       end
 
@@ -111,6 +125,8 @@ module TestApi
     describe "simple declaration" do
       before do
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
           attr :age, Integer
           attr :active, Boolean
@@ -305,6 +321,8 @@ def serialise(model_name)
     describe "explicit API name mapping with <=>" do
       before do
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           using RestEasy::Refinements
 
           attr :tax_reduction_list_url <=> '@urlTaxReductionList', String, :read_only, :optional
@@ -322,6 +340,8 @@ def serialise(model_name)
     describe "attribute flags" do
       it "supports :required flag" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String, :required
         end
 
@@ -332,6 +352,8 @@ def serialise(model_name)
 
       it "supports :optional flag" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String, :optional
         end
 
@@ -341,6 +363,8 @@ def serialise(model_name)
 
       it "supports :read_only flag" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :balance, Float, :read_only
         end
 
@@ -355,6 +379,8 @@ def serialise(model_name)
     describe "custom parse/serialise with block" do
       before do
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           using RestEasy::Refinements
 
           attr :clean_field <=> :raw_field, String do
@@ -395,6 +421,8 @@ def self.serialise(value)
         end
 
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           using RestEasy::Refinements
 
           attr :clean_field <=> :raw_field, String, mapper
@@ -427,6 +455,8 @@ def self.serialise(full_name)
         end
 
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :first_name, String
           attr :last_name, String
           attr :full_name, String, mapper
@@ -473,6 +503,8 @@ def self.serialise(street, city)
         end
 
         @resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :street, String
           attr :city, String
           attr :address, String, mapper
@@ -498,6 +530,8 @@ def self.serialise(street, city)
   describe "key" do
     it "declares the unique identifier attribute" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :document_number, Integer, :read_only
       end
 
@@ -508,6 +542,8 @@ def self.serialise(street, city)
 
     it "is equivalent to attr with :key flag" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :id, Integer, :key
       end
 
@@ -519,6 +555,8 @@ def self.serialise(street, city)
     it "warns when called more than once" do
       expect {
         Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           key :id, Integer
           key :other_id, Integer
         end
@@ -531,6 +569,8 @@ def self.serialise(street, city)
   describe "ignore" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         ignore :internal_field
       end
@@ -566,6 +606,8 @@ def self.serialise(street, city)
 
     it "does not warn about explicitly ignored fields" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String
         ignore :internal_field
       end
@@ -577,6 +619,11 @@ def self.serialise(street, city)
 
     it "warns about undeclared API fields" do
       resource_class = Class.new(described_class) do
+        configure do
+          conversions.json_attributes = :PascalCase
+          debug true
+        end
+
         attr :name, String
       end
 
@@ -591,6 +638,8 @@ def self.serialise(street, city)
   describe "synthetic attributes via attr block" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :first_name, String
         attr :last_name, String
 
@@ -655,6 +704,8 @@ def self.serialise(street, city)
   describe "bare block as implicit parse" do
     it "treats a block with params as an implicit parse block" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :full_name, String, :read_only do |first_name, last_name|
           "#{first_name} #{last_name}"
         end
@@ -670,6 +721,8 @@ def self.serialise(street, city)
 
     it "extracts source_fields from bare block param names" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :full_name, String, :read_only do |first_name, last_name|
           "#{first_name} #{last_name}"
         end
@@ -682,6 +735,8 @@ def self.serialise(street, city)
 
     it "works with single-param bare block for split pattern" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :city, String do |address|
           address["city"]
         end
@@ -696,6 +751,8 @@ def self.serialise(street, city)
 
     it "serialises under own API name when no serialise block is defined" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :city, String do |address|
           address["city"]
         end
@@ -716,6 +773,8 @@ def self.serialise(street, city)
   describe "multi-param serialise block" do
     it "gathers model values by param names and splats into block" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :street, String
         attr :city, String
 
@@ -733,6 +792,8 @@ def self.serialise(street, city)
 
     it "stores target_fields from serialise block param names" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :street, String
         attr :city, String
 
@@ -752,6 +813,8 @@ def self.serialise(street, city)
     describe "before_parse" do
       it "pre-processes API data before attribute parsing" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           before_parse do |api_data|
             api_data["Invoice"]
           end
@@ -769,6 +832,8 @@ def self.serialise(street, city)
         after_parse_called = false
 
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
 
           after_parse do |model|
@@ -786,6 +851,8 @@ def self.serialise(street, city)
         before_serialise_called = false
 
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
 
           before_serialise do |model|
@@ -802,6 +869,8 @@ def self.serialise(street, city)
     describe "after_serialise" do
       it "post-processes API data after serialisation" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
 
           after_serialise do |api_data|
@@ -819,6 +888,8 @@ def self.serialise(street, city)
     describe "before_parse with collections" do
       it "unwraps envelope before parsing a collection" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           before_parse do |api_data|
             api_data["Invoices"]
           end
@@ -841,6 +912,8 @@ def self.serialise(street, city)
     describe "hook inheritance" do
       it "inherits hooks from parent classes" do
         parent = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           before_parse do |api_data|
             api_data["Wrapper"]
           end
@@ -856,6 +929,8 @@ def self.serialise(street, city)
 
       it "resolves config from the calling class in inherited before_parse hook" do
         parent = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           settings do
             setting :instance_wrapper
           end
@@ -884,6 +959,8 @@ def self.serialise(street, city)
   describe "instance state" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :id, Integer
         attr :name, String
         ignore :internal
@@ -944,6 +1021,8 @@ def self.serialise(street, city)
   describe "change tracking" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :id, Integer
         attr :name, String
         attr :amount, Float
@@ -980,6 +1059,8 @@ def self.serialise(street, city)
   describe "serialisation" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :id, Integer, :read_only
         attr :name, String
         attr :balance, Float, :read_only
@@ -1027,6 +1108,8 @@ def self.serialise(street, city)
   describe "equality" do
     before do
       @resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :id, Integer
         attr :name, String
       end
@@ -1048,6 +1131,8 @@ def self.serialise(street, city)
 
     it "considers instances of different classes unequal" do
       other_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         key :id, Integer
         attr :name, String
       end
@@ -1064,6 +1149,8 @@ def self.serialise(street, city)
   describe "type coercion" do
     it "coerces string to integer" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :count, Integer
       end
 
@@ -1073,6 +1160,8 @@ def self.serialise(street, city)
 
     it "coerces string to float" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :amount, Float
       end
 
@@ -1082,6 +1171,8 @@ def self.serialise(street, city)
 
     it "supports type constraints" do
       resource_class = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         attr :name, String.constrained(max_size: 5)
       end
 
@@ -1093,6 +1184,8 @@ def self.serialise(street, city)
     context "via update" do
       it "coerces values through the attribute type" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :count, Integer
         end
 
@@ -1103,6 +1196,8 @@ def self.serialise(street, city)
 
       it "rejects values that violate constraints" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String.constrained(max_size: 5)
         end
 
@@ -1114,6 +1209,8 @@ def self.serialise(street, city)
 
       it "passes nil through without coercion" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
         end
 
@@ -1126,6 +1223,8 @@ def self.serialise(street, city)
     context "via stub" do
       it "coerces values through the attribute type" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :count, Integer
         end
 
@@ -1135,6 +1234,8 @@ def self.serialise(street, city)
 
       it "rejects values that violate constraints" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String.constrained(max_size: 5)
         end
 
@@ -1145,6 +1246,8 @@ def self.serialise(street, city)
 
       it "passes nil through without coercion" do
         resource_class = Class.new(described_class) do
+          configure { conversions.json_attributes = :PascalCase }
+
           attr :name, String
         end
 
@@ -1159,6 +1262,8 @@ def self.serialise(street, city)
   describe "settings" do
     it "declares a setting via the settings block" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1169,6 +1274,8 @@ def self.serialise(street, city)
 
     it "allows reading settings via config" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :collection_name, default: "items"
         end
@@ -1180,6 +1287,8 @@ def self.serialise(street, city)
 
     it "supports reader: true for accessor methods" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true, reader: true
         end
@@ -1190,6 +1299,8 @@ def self.serialise(street, city)
 
     it "inherits settings from parent resource" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1204,6 +1315,8 @@ def self.serialise(street, city)
 
     it "isolates config between sibling classes" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1221,6 +1334,8 @@ def self.serialise(street, city)
 
     it "allows child to override inherited defaults without affecting parent" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1235,6 +1350,8 @@ def self.serialise(street, city)
 
     it "accumulates settings from multiple levels" do
       grandparent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1256,6 +1373,8 @@ def self.serialise(street, city)
 
     it "exposes config on instances for use in hooks" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: true
         end
@@ -1268,6 +1387,8 @@ def self.serialise(street, city)
 
     it "exposes configure-set values on instances" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         configure do
           path "/invoices"
         end
@@ -1280,6 +1401,8 @@ def self.serialise(street, city)
 
     it "exposes inherited configure-set values on instances" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :wrapper, default: false
         end
@@ -1303,6 +1426,8 @@ def self.serialise(street, city)
   describe "configure" do
     it "sets a config value via method-call syntax" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :adapter, default: :rest
         end
@@ -1317,6 +1442,8 @@ def self.serialise(street, city)
 
     it "sets multiple values in one block" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :adapter, default: :rest
           setting :pool, default: 1
@@ -1334,6 +1461,8 @@ def self.serialise(street, city)
 
     it "works with nested settings" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :database do
             setting :dsn, default: "sqlite:memory"
@@ -1350,6 +1479,8 @@ def self.serialise(street, city)
 
     it "inherits settings and allows child to configure them" do
       parent = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :adapter, default: :rest
         end
@@ -1367,6 +1498,8 @@ def self.serialise(street, city)
 
     it "can be called after class definition" do
       resource = Class.new(described_class) do
+        configure { conversions.json_attributes = :PascalCase }
+
         settings do
           setting :pool, default: 1
         end

From d21f455d6a36bf196e0c62d651530a414453a4ad Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 16:16:05 +0200
Subject: [PATCH 2/6] Updates README.md with new config structure

---
 README.md | 41 +++++++++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/README.md b/README.md
index e3623f9..675aafc 100644
--- a/README.md
+++ b/README.md
@@ -34,7 +34,7 @@ module Acme
   configure do
     base_url "https://api.acme.com/v1"
     authentication RestEasy::Auth::PSK.new(api_key: ENV["ACME_API_KEY"])
-    attribute_convention :PascalCase
+    conversions.json_attributes = :PascalCase
   end
 end
 
@@ -85,19 +85,21 @@ module Fortnox
     base_url "https://api.fortnox.se/3"
     max_retries 3
     authentication RestEasy::Auth::PSK.new(api_key: ENV["FORTNOX_KEY"])
-    attribute_convention :PascalCase
+    conversions.json_attributes = :PascalCase
+    conversions.query_parameters = :PascalCase
   end
 end
 ```
 
 ### Available settings
 
-| Setting                | Default                    | Description                              |
-|------------------------|----------------------------|------------------------------------------|
-| `base_url`             | `"https://example.com"`    | Base URL for all requests                |
-| `max_retries`          | `3`                        | Retry count on request failure           |
-| `authentication`       | `Auth::Null.new`           | Authentication strategy                  |
-| `attribute_convention` | `:PascalCase`              | Naming convention for API field mapping  |
+| Setting                          | Default                    | Description                                       |
+|----------------------------------|----------------------------|---------------------------------------------------|
+| `base_url`                       | `"https://example.com"`    | Base URL for all requests                         |
+| `max_retries`                    | `3`                        | Retry count on request failure                    |
+| `authentication`                 | `Auth::Null.new`           | Authentication strategy                           |
+| `conversions.json_attributes`    | `:snake_case`              | Naming convention for JSON response/request fields|
+| `conversions.query_parameters`   | `:snake_case`              | Naming convention for query parameter keys        |
 
 ### Faraday middleware
 
@@ -189,7 +191,7 @@ The full `Dry::Types` vocabulary is available inside resource bodies — `Strict
 
 ### Naming conventions
 
-RestEasy automatically maps between Ruby's `snake_case` attribute names and the API's naming convention:
+RestEasy automatically maps between Ruby's `snake_case` attribute names and the API's naming convention. The `conversions` config controls this independently for JSON attributes and query parameters:
 
 | Convention    | Ruby attr          | API field            |
 |---------------|--------------------|----------------------|
@@ -197,12 +199,27 @@ RestEasy automatically maps between Ruby's `snake_case` attribute names and the
 | `:camelCase`  | `:document_number` | `"documentNumber"`   |
 | `:snake_case` | `:document_number` | `"document_number"`  |
 
-Set the convention at the module level (applies to all resources) or override per resource:
+Set conventions at the module level (applies to all resources):
 
 ```ruby
-attribute_convention :camelCase
+configure do
+  conversions.json_attributes = :camelCase
+  conversions.query_parameters = :PascalCase
+end
 ```
 
+Or override per resource:
+
+```ruby
+class MyAPI::Special < MyAPI::Resource
+  configure do
+    conversions.json_attributes = :PascalCase
+  end
+end
+```
+
+Query parameter keys are automatically transformed when calling `get` with `params:`. For example, with `query_parameters: :PascalCase`, `params: { sort_order: "asc" }` becomes `?SortOrder=asc` in the request.
+
 You can also provide a custom convention object with `parse(api_name)` and `serialise(model_name)` methods.
 
 ### Explicit name mapping
@@ -735,7 +752,7 @@ module MyAPI
     base_url "https://api.example.com/v1"
     max_retries 3
     authentication RestEasy::Auth::PSK.new(api_key: ENV["MY_API_KEY"])
-    attribute_convention :PascalCase
+    conversions.json_attributes = :PascalCase
   end
 end
 ```

From 4b2f10b20f9ed6f27c9cec5f6f84f6c8b8c4a027 Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 16:22:06 +0200
Subject: [PATCH 3/6] Moves resolver defaults to parent module settings

---
 lib/rest_easy/resource.rb                   |  7 +---
 lib/rest_easy/settings.rb                   |  4 +-
 spec/rest_easy/resource/conversions_spec.rb | 41 +--------------------
 spec/rest_easy/resource/crud_spec.rb        |  2 +-
 spec/rest_easy/resource/http_spec.rb        |  1 +
 spec/rest_easy/resource/inheritance_spec.rb |  2 +-
 6 files changed, 9 insertions(+), 48 deletions(-)

diff --git a/lib/rest_easy/resource.rb b/lib/rest_easy/resource.rb
index 41c135d..37da290 100644
--- a/lib/rest_easy/resource.rb
+++ b/lib/rest_easy/resource.rb
@@ -153,13 +153,10 @@ def metadata(**kwargs)
       def resolved_conversions
         @resolved_conversions ||= begin
           qp = config.conversions.query_parameters ||
-               parent&.config&.conversions&.query_parameters ||
-               :snake_case
+               parent&.config&.conversions&.query_parameters
 
           ja = config.conversions.json_attributes ||
-               parent&.config&.conversions&.json_attributes ||
-               parent&.config&.attribute_convention || # BC: old setting as fallback
-               :snake_case
+               parent&.config&.conversions&.json_attributes
 
           Conventions::ConventionPair.new(
             query_parameters: Conventions.resolve(qp),
diff --git a/lib/rest_easy/settings.rb b/lib/rest_easy/settings.rb
index d261bb1..038253f 100644
--- a/lib/rest_easy/settings.rb
+++ b/lib/rest_easy/settings.rb
@@ -12,8 +12,8 @@ class Settings
     setting :attribute_convention, default: :PascalCase, reader: true # deprecated, kept for BC
 
     setting :conversions do
-      setting :query_parameters, reader: true  # nil default — :snake_case resolved in Resource
-      setting :json_attributes, reader: true   # nil default — :snake_case resolved in Resource
+      setting :query_parameters, default: :snake_case, reader: true
+      setting :json_attributes, default: :snake_case, reader: true
     end
   end
 end
diff --git a/spec/rest_easy/resource/conversions_spec.rb b/spec/rest_easy/resource/conversions_spec.rb
index e135e80..473ebc1 100644
--- a/spec/rest_easy/resource/conversions_spec.rb
+++ b/spec/rest_easy/resource/conversions_spec.rb
@@ -248,41 +248,6 @@ class MixedApi::Item < RestEasy::Resource
   # ── Backwards compatibility ─────────────────────────────────────────
 
   describe "backwards compatibility" do
-    describe "module-level attribute_convention" do
-      before(:all) do
-        module BCModuleApi
-          extend RestEasy
-
-          configure do |config|
-            config.attribute_convention = :PascalCase
-          end
-        end
-
-        class BCModuleApi::Invoice < RestEasy::Resource
-          attr :customer_name, String
-        end
-      end
-
-      after(:all) do
-        Object.send(:remove_const, :BCModuleApi)
-      end
-
-      it "resolves json_attributes from old attribute_convention setting" do
-        conv = BCModuleApi::Invoice.resolved_conversions
-        expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
-      end
-
-      it "defaults query_parameters to snake_case" do
-        conv = BCModuleApi::Invoice.resolved_conversions
-        expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
-      end
-
-      it "parses with the old convention" do
-        instance = BCModuleApi::Invoice.parse({ "CustomerName" => "Acme" })
-        expect(instance.customer_name).to eq("Acme")
-      end
-    end
-
     describe "resource-level attribute_convention" do
       it "sets json_attributes and emits a deprecation warning" do
         resource_class = Class.new(RestEasy::Resource)
@@ -324,11 +289,9 @@ class DefaultApi::Thing < RestEasy::Resource
       Object.send(:remove_const, :DefaultApi)
     end
 
-    it "falls back to attribute_convention default for json_attributes" do
-      # The old attribute_convention defaults to :PascalCase on Settings,
-      # so json_attributes picks that up via the BC fallback
+    it "defaults json_attributes to snake_case" do
       conv = DefaultApi::Thing.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      expect(conv.json_attributes).to be_a(RestEasy::Conventions::SnakeCase)
     end
 
     it "defaults query_parameters to snake_case" do
diff --git a/spec/rest_easy/resource/crud_spec.rb b/spec/rest_easy/resource/crud_spec.rb
index 984438d..fe1f441 100644
--- a/spec/rest_easy/resource/crud_spec.rb
+++ b/spec/rest_easy/resource/crud_spec.rb
@@ -7,7 +7,7 @@ module CrudTestApi
 
       configure do |config|
         config.base_url = "https://api.example.com/v1"
-        config.attribute_convention = :PascalCase
+        config.conversions.json_attributes = :PascalCase
         config.max_retries = 3
       end
     end
diff --git a/spec/rest_easy/resource/http_spec.rb b/spec/rest_easy/resource/http_spec.rb
index dbe97ca..7b85c33 100644
--- a/spec/rest_easy/resource/http_spec.rb
+++ b/spec/rest_easy/resource/http_spec.rb
@@ -8,6 +8,7 @@ module HttpTestApi
       configure do |config|
         config.base_url = "https://api.example.com/v1"
         config.max_retries = 3
+        config.conversions.json_attributes = :PascalCase
       end
     end
 
diff --git a/spec/rest_easy/resource/inheritance_spec.rb b/spec/rest_easy/resource/inheritance_spec.rb
index 7f2922f..ad0b19f 100644
--- a/spec/rest_easy/resource/inheritance_spec.rb
+++ b/spec/rest_easy/resource/inheritance_spec.rb
@@ -10,7 +10,7 @@ module InheritanceTestApi
 
       configure do |config|
         config.base_url = "https://api.example.com"
-        config.attribute_convention = :PascalCase
+        config.conversions.json_attributes = :PascalCase
       end
     end
 

From 82d9f0954ec6b0c8f4cea63bb94788963265a40d Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 16:29:44 +0200
Subject: [PATCH 4/6] Proxies old module setting to new config

---
 lib/rest_easy.rb                            |  7 +++++
 lib/rest_easy/settings.rb                   |  2 +-
 spec/rest_easy/resource/conversions_spec.rb | 35 +++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/lib/rest_easy.rb b/lib/rest_easy.rb
index 8f19cf4..880039b 100644
--- a/lib/rest_easy.rb
+++ b/lib/rest_easy.rb
@@ -83,6 +83,13 @@ def configure(&block)
         else
           yield self::Settings.config
         end
+
+        # BC: propagate deprecated attribute_convention to conversions
+        ac = self::Settings.config.attribute_convention
+        if ac
+          warn "RestEasy: attribute_convention is deprecated, use `conversions.json_attributes = #{ac.inspect}` instead"
+          self::Settings.config.conversions.json_attributes = ac
+        end
       end
     end
 
diff --git a/lib/rest_easy/settings.rb b/lib/rest_easy/settings.rb
index 038253f..59ff806 100644
--- a/lib/rest_easy/settings.rb
+++ b/lib/rest_easy/settings.rb
@@ -9,7 +9,7 @@ class Settings
     setting :base_url, default: "https://example.com", reader: true
     setting :max_retries, default: 3, reader: true
     setting :authentication, default: Auth::Null.new, reader: true
-    setting :attribute_convention, default: :PascalCase, reader: true # deprecated, kept for BC
+    setting :attribute_convention # deprecated — propagated to conversions.json_attributes in configure
 
     setting :conversions do
       setting :query_parameters, default: :snake_case, reader: true
diff --git a/spec/rest_easy/resource/conversions_spec.rb b/spec/rest_easy/resource/conversions_spec.rb
index 473ebc1..d9be87c 100644
--- a/spec/rest_easy/resource/conversions_spec.rb
+++ b/spec/rest_easy/resource/conversions_spec.rb
@@ -248,6 +248,41 @@ class MixedApi::Item < RestEasy::Resource
   # ── Backwards compatibility ─────────────────────────────────────────
 
   describe "backwards compatibility" do
+    describe "module-level attribute_convention" do
+      before(:all) do
+        module BCModuleApi
+          extend RestEasy
+
+          configure do |config|
+            config.attribute_convention = :PascalCase
+          end
+        end
+
+        class BCModuleApi::Invoice < RestEasy::Resource
+          attr :customer_name, String
+        end
+      end
+
+      after(:all) do
+        Object.send(:remove_const, :BCModuleApi)
+      end
+
+      it "propagates to conversions.json_attributes" do
+        conv = BCModuleApi::Invoice.resolved_conversions
+        expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      end
+
+      it "defaults query_parameters to snake_case" do
+        conv = BCModuleApi::Invoice.resolved_conversions
+        expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
+      end
+
+      it "parses with the propagated convention" do
+        instance = BCModuleApi::Invoice.parse({ "CustomerName" => "Acme" })
+        expect(instance.customer_name).to eq("Acme")
+      end
+    end
+
     describe "resource-level attribute_convention" do
       it "sets json_attributes and emits a deprecation warning" do
         resource_class = Class.new(RestEasy::Resource)

From f540047d71eb62cb41814c3247580b71ea318f95 Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 16:58:51 +0200
Subject: [PATCH 5/6] Simplifies the memoized converter functions

---
 lib/rest_easy/conventions.rb                |  2 -
 lib/rest_easy/resource.rb                   | 35 ++++++++-------
 spec/rest_easy/resource/conversions_spec.rb | 48 ++++++++-------------
 3 files changed, 34 insertions(+), 51 deletions(-)

diff --git a/lib/rest_easy/conventions.rb b/lib/rest_easy/conventions.rb
index 13bea6d..f0b3307 100644
--- a/lib/rest_easy/conventions.rb
+++ b/lib/rest_easy/conventions.rb
@@ -56,8 +56,6 @@ def serialise(model_name)
       snake_case: SnakeCase.new
     }.freeze
 
-    ConventionPair = Struct.new(:query_parameters, :json_attributes, keyword_init: true)
-
     def self.resolve(convention)
       case convention
       when Symbol
diff --git a/lib/rest_easy/resource.rb b/lib/rest_easy/resource.rb
index 37da290..1ae869a 100644
--- a/lib/rest_easy/resource.rb
+++ b/lib/rest_easy/resource.rb
@@ -150,19 +150,18 @@ def metadata(**kwargs)
 
       # -- conversions ---------------------------------------------------
 
-      def resolved_conversions
-        @resolved_conversions ||= begin
-          qp = config.conversions.query_parameters ||
-               parent&.config&.conversions&.query_parameters
-
-          ja = config.conversions.json_attributes ||
-               parent&.config&.conversions&.json_attributes
-
-          Conventions::ConventionPair.new(
-            query_parameters: Conventions.resolve(qp),
-            json_attributes: Conventions.resolve(ja)
-          )
-        end
+      def json_attribute_converter
+        @json_attribute_converter ||= Conventions.resolve(
+          config.conversions.json_attributes ||
+          parent&.config&.conversions&.json_attributes
+        )
+      end
+
+      def query_parameter_converter
+        @query_parameter_converter ||= Conventions.resolve(
+          config.conversions.query_parameters ||
+          parent&.config&.conversions&.query_parameters
+        )
       end
 
       # -- attribute_convention (deprecated) -------------------------------
@@ -171,9 +170,9 @@ def attribute_convention(value = nil)
         if value
           warn "RestEasy: attribute_convention is deprecated, use `configure { conversions.json_attributes = #{value.inspect} }` instead"
           config.conversions.json_attributes = value
-          @resolved_conversions = nil # bust memoization
+          @json_attribute_converter = nil # bust memoization
         end
-        resolved_conversions.json_attributes
+        json_attribute_converter
       end
 
       private
@@ -212,7 +211,7 @@ def attr(name_or_mapping, *args, &block)
           attribute_api_name = name_or_mapping[1].to_s
         else
           attribute_model_name = name_or_mapping.to_sym
-          attribute_api_name = resolved_conversions.json_attributes.serialise(attribute_model_name)
+          attribute_api_name = json_attribute_converter.serialise(attribute_model_name)
         end
 
         # Extract type (non-Symbol), flags (Symbols), and optional mapper object
@@ -481,7 +480,7 @@ def delete(id)
 
       def get(path:, params: {}, headers: {})
         if params.any?
-          conv = resolved_conversions.query_parameters
+          conv = query_parameter_converter
           params = params.transform_keys { |k| conv.serialise(k) }
         end
         parent.get(path:, params:, headers:)
@@ -603,7 +602,7 @@ def serialise
           serialised = attr_def.serialise_value(value)
           if serialised.is_a?(::Array)
             # Array return: zip with source field API names
-            convention = klass.resolved_conversions.json_attributes
+            convention = klass.json_attribute_converter
             attr_def.source_fields.zip(serialised).each do |field_name, field_value|
               api_key = convention.serialise(field_name)
               result[api_key] = field_value
diff --git a/spec/rest_easy/resource/conversions_spec.rb b/spec/rest_easy/resource/conversions_spec.rb
index d9be87c..9b8c11b 100644
--- a/spec/rest_easy/resource/conversions_spec.rb
+++ b/spec/rest_easy/resource/conversions_spec.rb
@@ -39,13 +39,11 @@ class ConvTestApi::Invoice < RestEasy::Resource
     end
 
     it "resolves json_attributes from module config" do
-      conv = ConvTestApi::Invoice.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      expect(ConvTestApi::Invoice.json_attribute_converter).to be_a(RestEasy::Conventions::PascalCase)
     end
 
     it "resolves query_parameters from module config" do
-      conv = ConvTestApi::Invoice.resolved_conversions
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::CamelCase)
+      expect(ConvTestApi::Invoice.query_parameter_converter).to be_a(RestEasy::Conventions::CamelCase)
     end
 
     it "parses API data using json_attributes convention" do
@@ -125,15 +123,13 @@ class ResOverrideApi::Custom < ResOverrideApi::Base
     end
 
     it "inherits module-level convention when not overridden" do
-      conv = ResOverrideApi::Standard.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::CamelCase)
+      expect(ResOverrideApi::Standard.json_attribute_converter).to be_a(RestEasy::Conventions::CamelCase)
+      expect(ResOverrideApi::Standard.query_parameter_converter).to be_a(RestEasy::Conventions::CamelCase)
     end
 
     it "uses resource-level convention when overridden" do
-      conv = ResOverrideApi::Custom.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+      expect(ResOverrideApi::Custom.json_attribute_converter).to be_a(RestEasy::Conventions::PascalCase)
+      expect(ResOverrideApi::Custom.query_parameter_converter).to be_a(RestEasy::Conventions::PascalCase)
     end
 
     it "parses with inherited convention" do
@@ -147,11 +143,8 @@ class ResOverrideApi::Custom < ResOverrideApi::Base
     end
 
     it "does not affect sibling resources" do
-      standard_conv = ResOverrideApi::Standard.resolved_conversions
-      custom_conv = ResOverrideApi::Custom.resolved_conversions
-
-      expect(standard_conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
-      expect(custom_conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+      expect(ResOverrideApi::Standard.json_attribute_converter).to be_a(RestEasy::Conventions::CamelCase)
+      expect(ResOverrideApi::Custom.json_attribute_converter).to be_a(RestEasy::Conventions::PascalCase)
     end
   end
 
@@ -183,13 +176,11 @@ class PartialApi::Resource < RestEasy::Resource
     end
 
     it "uses overridden query_parameters" do
-      conv = PartialApi::Resource.resolved_conversions
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+      expect(PartialApi::Resource.query_parameter_converter).to be_a(RestEasy::Conventions::PascalCase)
     end
 
     it "inherits json_attributes from module" do
-      conv = PartialApi::Resource.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+      expect(PartialApi::Resource.json_attribute_converter).to be_a(RestEasy::Conventions::CamelCase)
     end
   end
 
@@ -217,9 +208,8 @@ class MixedApi::Item < RestEasy::Resource
     end
 
     it "uses different conventions for attributes and parameters" do
-      conv = MixedApi::Item.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::PascalCase)
+      expect(MixedApi::Item.json_attribute_converter).to be_a(RestEasy::Conventions::CamelCase)
+      expect(MixedApi::Item.query_parameter_converter).to be_a(RestEasy::Conventions::PascalCase)
     end
 
     it "serialises attributes as camelCase" do
@@ -268,13 +258,11 @@ class BCModuleApi::Invoice < RestEasy::Resource
       end
 
       it "propagates to conversions.json_attributes" do
-        conv = BCModuleApi::Invoice.resolved_conversions
-        expect(conv.json_attributes).to be_a(RestEasy::Conventions::PascalCase)
+        expect(BCModuleApi::Invoice.json_attribute_converter).to be_a(RestEasy::Conventions::PascalCase)
       end
 
       it "defaults query_parameters to snake_case" do
-        conv = BCModuleApi::Invoice.resolved_conversions
-        expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
+        expect(BCModuleApi::Invoice.query_parameter_converter).to be_a(RestEasy::Conventions::SnakeCase)
       end
 
       it "parses with the propagated convention" do
@@ -291,7 +279,7 @@ class BCModuleApi::Invoice < RestEasy::Resource
           resource_class.attribute_convention :camelCase
         }.to output(/deprecated/).to_stderr
 
-        expect(resource_class.resolved_conversions.json_attributes).to be_a(RestEasy::Conventions::CamelCase)
+        expect(resource_class.json_attribute_converter).to be_a(RestEasy::Conventions::CamelCase)
       end
 
       it "still works as a getter" do
@@ -325,13 +313,11 @@ class DefaultApi::Thing < RestEasy::Resource
     end
 
     it "defaults json_attributes to snake_case" do
-      conv = DefaultApi::Thing.resolved_conversions
-      expect(conv.json_attributes).to be_a(RestEasy::Conventions::SnakeCase)
+      expect(DefaultApi::Thing.json_attribute_converter).to be_a(RestEasy::Conventions::SnakeCase)
     end
 
     it "defaults query_parameters to snake_case" do
-      conv = DefaultApi::Thing.resolved_conversions
-      expect(conv.query_parameters).to be_a(RestEasy::Conventions::SnakeCase)
+      expect(DefaultApi::Thing.query_parameter_converter).to be_a(RestEasy::Conventions::SnakeCase)
     end
   end
 end

From 8991cd7e246b9d1a2beb9a6ec0a86e37bf760301 Mon Sep 17 00:00:00 2001
From: Jonas Schubert Erlandsson <jonas@accodeing.com>
Date: Wed, 25 Mar 2026 17:03:40 +0200
Subject: [PATCH 6/6] Simplifies query param conversion logic

---
 lib/rest_easy/resource.rb | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/rest_easy/resource.rb b/lib/rest_easy/resource.rb
index 1ae869a..9ce8258 100644
--- a/lib/rest_easy/resource.rb
+++ b/lib/rest_easy/resource.rb
@@ -479,10 +479,7 @@ def delete(id)
       # HTTP primitives — delegate to the parent API module's connection
 
       def get(path:, params: {}, headers: {})
-        if params.any?
-          conv = query_parameter_converter
-          params = params.transform_keys { |k| conv.serialise(k) }
-        end
+        params.transform_keys! { |k| query_parameter_converter.serialise(k) }
         parent.get(path:, params:, headers:)
       end