Renderer - wip

Signed-off-by: Jordan Hollinger <[email protected]>

lib/blueprinter.rb

@@ -6,6 +6,7 @@ module Blueprinter
   autoload :Configuration, 'blueprinter/configuration'
   autoload :Errors, 'blueprinter/errors'
   autoload :Extension, 'blueprinter/extension'
+  autoload :Hooks, 'blueprinter/hooks'
   autoload :Transformer, 'blueprinter/transformer'
   autoload :V2, 'blueprinter/v2'
 

lib/blueprinter/base.rb

@@ -246,7 +246,7 @@ def self.render_as_json(object, options = {})
     def self.prepare(object, view_name:, local_options:, root: nil, meta: nil)
       raise BlueprinterError, "View '#{view_name}' is not defined" unless view_collection.view? view_name
 
-      object = Blueprinter.configuration.extensions.pre_render(object, self, view_name, local_options)
+      object = Blueprinter.configuration.hooks.reduce(:pre_render, object) { |val| [val, self, view_name, local_options] }
       data = prepare_data(object, view_name, local_options)
       prepend_root_and_meta(data, root, meta)
     end

lib/blueprinter/configuration.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require 'json'
-require 'blueprinter/extensions'
+require 'blueprinter/hooks'
 require 'blueprinter/extractors/auto_extractor'
 
 module Blueprinter
@@ -27,11 +27,15 @@ def initialize
     end
 
     def extensions
-      @extensions ||= Extensions.new
+      @extensions ||= []
     end
 
     def extensions=(list)
-      @extensions = Extensions.new(list)
+      @extensions = list
+    end
+
+    def hooks
+      @hooks ||= Blueprinter::Hooks.new(extensions)
     end
 
     def array_like_classes

lib/blueprinter/extension.rb

@@ -2,11 +2,188 @@
 
 module Blueprinter
   #
-  # Base class for all extensions. All extension methods are implemented as no-ops.
+  # Base class for all extensions.
+  #
+  # V2 hook call order:
+  #  - collection? (skipped when using render_object/render_collection)
+  #  - input_object | input_collection
+  #  - each_input
+  #  - field_value
+  #  - formatters
+  #  - exclude_field?
+  #  - object_value
+  #  - exclude_object?
+  #  - collection_value
+  #  - exclude_collection?
+  #  - each_output
+  #  - output_object | output_collection
+  #
+  # V1 hook call order:
+  #  - pre_render
   #
   class Extension
+    class << self
+      attr_accessor :formatters
+    end
+
+    def self.inherited(ext)
+      ext.formatters = {}
+    end
+
+    #
+    # Add a formatter for instances of the given class.
+    #
+    # Example:
+    #   class MyExtension < Blueprinter::Extension
+    #     format(Time) { |context| context.value.iso8601 }
+    #     format Date, :date_str
+    #
+    #     def date_str(context)
+    #       context.value.iso8601
+    #     end
+    #   end
+    #
+    # @param klass [Class] The class of objects to format
+    # @param formatter_method [Symbol] Name of a public instance method to call for formatting
+    # @yield Do formatting in the block instead
+    #
+    def self.format(klass, formatter_method = nil, &formatter_block)
+      formatters[klass] = formatter_method || formatter_block
+    end
+
+    #
+    # Returns true if the given object should be considered a collection.
+    #
+    # @param [Object]
+    # @return [Boolean]
+    #
+    def collection?(_object)
+      false
+    end
+
+    #
+    # Modify or replace the object passed to render/render_object.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def input_object(context)
+      context.object
+    end
+
+
+    #
+    # Modify or replace the collection passed to render/render_collection.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def input_collection(context)
+      context.object
+    end
+
+    #
+    # Modify or replace the object result before final render (e.g. to JSON).
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def output_object(context)
+      context.value
+    end
+
+    #
+    # Modify or replace the collection result before final render (e.g. to JSON).
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def output_collection(context)
+      context.value
+    end
+
+    #
+    # Modify or replace the object that's passed into each Blueprint.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def each_input(context)
+      context.object
+    end
+
+    #
+    # Modify or replace the output from each Blueprint.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def each_output(context)
+      context.value
+    end
+
+    #
+    # Modify or replace the value used for the field.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def field_value(context)
+      context.value
+    end
+
+    #
+    # Modify or replace the value used for the object.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def object_value(context)
+      context.value
+    end
+
+    #
+    # Modify or replace the value used for the collection.
+    #
+    # @param context [Blueprinter::V2::Serializer::Context]
+    # @return [Object]
+    #
+    def collection_value(context)
+      context.value
+    end
+
+    #
+    # Return true to exclude this field from the result.
+    #
+    # @param _context [Blueprinter::V2::Serializer::Context]
+    # @return [Boolean]
+    #
+    def exclude_field?(_context)
+      false
+    end
+
+    #
+    # Return true to exclude this object from the result.
+    #
+    # @param _context [Blueprinter::V2::Serializer::Context]
+    # @return [Boolean]
+    #
+    def exclude_object?(_context)
+      false
+    end
+
+    #
+    # Return true to exclude this collection from the result.
+    #
+    # @param _context [Blueprinter::V2::Serializer::Context]
+    # @return [Boolean]
+    #
+    def exclude_collection?(_context)
+      false
+    end
+
     #
-    # Called eary during "render", this method receives the object to be rendered and
+    # Called eary during "render" in V1, this method receives the object to be rendered and
     # may return a modified (or new) object to be rendered.
     #
     # @param object [Object] The object to be rendered

lib/blueprinter/hooks.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module Blueprinter
+  # An interface for running extension hooks
+  class Hooks
+    def initialize(extensions)
+      @hooks = Extension.public_instance_methods(false).each_with_object({}) do |hook, acc|
+        acc[hook] = extensions.
+          select { |ext| ext.class.public_instance_methods(false).include? hook }.
+          map { |ext| ext.public_method(hook) }
+      end
+    end
+
+    #
+    # Return true if any of "hook" returns truthy.
+    #
+    # @param hook [Symbol] Name of hook to call
+    # @return [Boolean]
+    #
+    def any?(hook, *args)
+      @hooks.fetch(hook).any? { |h| h.call(*args) }
+    end
+
+    #
+    # Call the hooks in series, passing the output of one to the block, which returns the args for the next.
+    #
+    # If the hook requires multiple arguments, the block should return an array.
+    #
+    # @param hook [Symbol] Name of hook to call
+    # @param initial_value [Object] The starting value for the block
+    # @return [Object] The last hook's return value
+    #
+    def reduce(hook, initial_value)
+      @hooks.fetch(hook).reduce(initial_value) do |val, h|
+        args = yield val
+        args.is_a?(Array) ? h.call(*args) : h.call(args)
+      end
+    end
+  end
+end

lib/blueprinter/v2.rb

@@ -1,3 +1,18 @@
 # frozen_string_literal: true
 
-require 'blueprinter/v2/base'
+require 'blueprinter/v2/fields'
+
+module Blueprinter
+  module V2
+    autoload :Base, 'blueprinter/v2/base'
+    autoload :DSL, 'blueprinter/v2/dsl'
+    autoload :Extensions, 'blueprinter/v2/extensions'
+    autoload :Extractor, 'blueprinter/v2/extractor'
+    autoload :Formatter, 'blueprinter/v2/formatter'
+    autoload :InstanceCache, 'blueprinter/v2/instance_cache'
+    autoload :Reflection, 'blueprinter/v2/reflection'
+    autoload :Render, 'blueprinter/v2/render'
+    autoload :Serializer, 'blueprinter/v2/serializer'
+    autoload :ViewBuilder, 'blueprinter/v2/view_builder'
+  end
+end