Make JSONAPI::Rails::ActiveModelError inherit from JSONAPI::Serializable::Error, and add tests.

Author: Michael Deutsch

lib/jsonapi/rails/active_model_error.rb

@@ -0,0 +1,24 @@
+module JSONAPI
+  module Rails
+    class ActiveModelError < JSONAPI::Serializable::Error
+      def self.from_errors(errors, reverse_mapping)
+        errors.keys.flat_map do |field|
+          errors.full_messages_for(field).map do |message|
+            new(field, message, reverse_mapping[field])
+          end
+        end
+      end
+
+      def initialize(field, message, source)
+        super(field: field, message: message, source: source)
+      end
+
+      title { @field.present? ? "Invalid #{@field}" : 'Invalid record' }
+      detail { @message }
+
+      source do
+        pointer @source unless @source.nil?
+      end
+    end
+  end
+end

lib/jsonapi/rails/active_model_errors.rb

@@ -1,6 +1,7 @@
 require 'rails/railtie'
 require 'action_controller'
 require 'active_support'
+require 'active_model'
 
 require 'jsonapi/rails/parser'
 require 'jsonapi/rails/renderer'

lib/jsonapi/rails/railtie.rb

@@ -1,4 +1,4 @@
-require 'jsonapi/rails/active_model_errors'
+require 'jsonapi/rails/active_model_error'
 require 'jsonapi/serializable/renderer'
 
 module JSONAPI
@@ -24,7 +24,7 @@ def self.render(errors, options)
           if error.respond_to?(:as_jsonapi)
             error
           elsif error.is_a?(ActiveModel::Errors)
-            ActiveModelErrors.new(error, options[:_reverse_mapping]).to_a
+            ActiveModelError.from_errors(error, options[:_reverse_mapping]).to_a
           elsif error.is_a?(Hash)
             JSONAPI::Serializable::Error.create(error)
           else

lib/jsonapi/rails/renderer.rb

@@ -0,0 +1,26 @@
+require 'spec_helper'
+
+describe JSONAPI::Rails::ActiveModelError do
+  class Thing
+    include ActiveModel::Model
+    attr_accessor :name, :description
+    validates :name, presence: true
+    validates :description, presence: true
+  end
+
+  let(:reverse_mapping) { { name: 'data/attributes/name', description: 'data/attributes/description' } }
+
+  context 'building from a model' do
+    it 'converts the model errors' do
+      invalid_thing = Thing.new
+      expect(invalid_thing.valid?).to be false
+
+      errors = JSONAPI::Rails::ActiveModelError.from_errors(invalid_thing.errors, reverse_mapping)
+      errors.sort_by! { |e| e.send(:title) }
+
+      expect(errors.size).to eq 2
+      expect(errors[0].send(:title)).to eq 'Invalid description'
+      expect(errors[0].send(:detail)).to eq "Description can't be blank"
+    end
+  end
+end

spec/active_model_error_spec.rb

@@ -24,7 +24,7 @@ def create
     p request.env['jsonapi_deserializable.reverse_mapping']
 
     unless tweet.save
-      render jsonapi_errors: tweet.errors
+      render jsonapi_errors: tweet.errors, status: :unprocessable_entity
       return
     end
 

spec/dummy/app/controllers/tweets_controller.rb

@@ -1,4 +1,6 @@
 class Tweet < ApplicationRecord
   belongs_to :parent, optional: true
   belongs_to :author, class_name: 'User'
+
+  validates :content, presence: true
 end

spec/dummy/app/models/tweet.rb

@@ -96,4 +96,28 @@ def body
     expect(response.body).to be_valid_jsonapi
     expect(body['data'].first).to eq(second_tweet['data'])
   end
+
+  it 'renders errors when trying to create an invalid tweet' do
+    # Post an invalid tweet
+    params = {
+      data: {
+        type: 'tweets',
+        attributes: {}
+      }
+    }
+    post '/tweets',
+         params: params,
+         as: :json,
+         headers: headers.merge('CONTENT_TYPE' => 'application/vnd.api+json')
+    expect(response).to have_http_status(422)
+    expect(response.body).to be_valid_jsonapi
+    expect(response.body).to match_schema do
+      required(:errors).each do
+        required(:title).value(eql?: 'Invalid content')
+        required(:detail).value(eql?: "Content can't be blank")
+        required(:source).value(:hash?)
+        required(:source).value(:empty?)
+      end
+    end
+  end
 end

spec/requests/crud_spec.rb

@@ -1,4 +1,5 @@
 require 'jsonapi/parser'
+require 'jsonapi/rails'
 
 # This file was generated by the `rails generate rspec:install` command. Conventionally, all
 # specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.