Merge pull request #1 from barkbox/pagination-links

Pagination links in ams

Gemfile.lock

@@ -1,104 +1,122 @@
 PATH
   remote: .
   specs:
-    paging_cursor (0.0.4)
+    paging_cursor (0.2.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
-    actionmailer (4.0.13)
-      actionpack (= 4.0.13)
+    actionmailer (4.1.16)
+      actionpack (= 4.1.16)
+      actionview (= 4.1.16)
       mail (~> 2.5, >= 2.5.4)
-    actionpack (4.0.13)
-      activesupport (= 4.0.13)
-      builder (~> 3.1.0)
-      erubis (~> 2.7.0)
+    actionpack (4.1.16)
+      actionview (= 4.1.16)
+      activesupport (= 4.1.16)
       rack (~> 1.5.2)
       rack-test (~> 0.6.2)
-    activemodel (4.0.13)
-      activesupport (= 4.0.13)
-      builder (~> 3.1.0)
-    activerecord (4.0.13)
-      activemodel (= 4.0.13)
-      activerecord-deprecated_finders (~> 1.0.2)
-      activesupport (= 4.0.13)
-      arel (~> 4.0.0)
-    activerecord-deprecated_finders (1.0.4)
-    activesupport (4.0.13)
+    actionview (4.1.16)
+      activesupport (= 4.1.16)
+      builder (~> 3.1)
+      erubis (~> 2.7.0)
+    active_model_serializers (0.10.4)
+      actionpack (>= 4.1, < 6)
+      activemodel (>= 4.1, < 6)
+      case_transform (>= 0.2)
+      jsonapi (= 0.1.1.beta6)
+    activemodel (4.1.16)
+      activesupport (= 4.1.16)
+      builder (~> 3.1)
+    activerecord (4.1.16)
+      activemodel (= 4.1.16)
+      activesupport (= 4.1.16)
+      arel (~> 5.0.0)
+    activesupport (4.1.16)
       i18n (~> 0.6, >= 0.6.9)
-      minitest (~> 4.2)
-      multi_json (~> 1.3)
+      json (~> 1.7, >= 1.7.7)
+      minitest (~> 5.1)
       thread_safe (~> 0.1)
-      tzinfo (~> 0.3.37)
-    arel (4.0.2)
-    builder (3.1.4)
-    concurrent-ruby (1.0.1)
-    diff-lcs (1.2.5)
+      tzinfo (~> 1.1)
+    arel (5.0.1.20140414130214)
+    builder (3.2.3)
+    case_transform (0.2)
+      activesupport
+    concurrent-ruby (1.0.5)
+    diff-lcs (1.3)
     erubis (2.7.0)
-    i18n (0.7.0)
+    i18n (0.8.1)
+    json (1.8.6)
+    jsonapi (0.1.1.beta6)
+      jsonapi-parser (= 0.1.1.beta3)
+      jsonapi-renderer (= 0.1.1.beta1)
+    jsonapi-parser (0.1.1.beta3)
+    jsonapi-renderer (0.1.1.beta1)
     mail (2.6.4)
       mime-types (>= 1.16, < 4)
-    mime-types (3.0)
+    mime-types (3.1)
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2016.0221)
-    minitest (4.7.5)
-    multi_json (1.11.3)
+    mime-types-data (3.2016.0521)
+    minitest (5.10.1)
     rack (1.5.5)
     rack-test (0.6.3)
       rack (>= 1.0)
-    rails (4.0.13)
-      actionmailer (= 4.0.13)
-      actionpack (= 4.0.13)
-      activerecord (= 4.0.13)
-      activesupport (= 4.0.13)
+    rails (4.1.16)
+      actionmailer (= 4.1.16)
+      actionpack (= 4.1.16)
+      actionview (= 4.1.16)
+      activemodel (= 4.1.16)
+      activerecord (= 4.1.16)
+      activesupport (= 4.1.16)
       bundler (>= 1.3.0, < 2.0)
-      railties (= 4.0.13)
+      railties (= 4.1.16)
       sprockets-rails (~> 2.0)
-    railties (4.0.13)
-      actionpack (= 4.0.13)
-      activesupport (= 4.0.13)
+    railties (4.1.16)
+      actionpack (= 4.1.16)
+      activesupport (= 4.1.16)
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
-    rake (11.1.2)
-    rspec (3.4.0)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-    rspec-core (3.4.4)
-      rspec-support (~> 3.4.0)
-    rspec-expectations (3.4.0)
+    rake (12.0.0)
+    rspec (3.5.0)
+      rspec-core (~> 3.5.0)
+      rspec-expectations (~> 3.5.0)
+      rspec-mocks (~> 3.5.0)
+    rspec-core (3.5.4)
+      rspec-support (~> 3.5.0)
+    rspec-expectations (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-mocks (3.4.1)
+      rspec-support (~> 3.5.0)
+    rspec-mocks (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-rails (3.4.2)
-      actionpack (>= 3.0, < 4.3)
-      activesupport (>= 3.0, < 4.3)
-      railties (>= 3.0, < 4.3)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-      rspec-support (~> 3.4.0)
-    rspec-support (3.4.1)
-    sprockets (3.6.0)
+      rspec-support (~> 3.5.0)
+    rspec-rails (3.5.2)
+      actionpack (>= 3.0)
+      activesupport (>= 3.0)
+      railties (>= 3.0)
+      rspec-core (~> 3.5.0)
+      rspec-expectations (~> 3.5.0)
+      rspec-mocks (~> 3.5.0)
+      rspec-support (~> 3.5.0)
+    rspec-support (3.5.0)
+    sprockets (3.7.1)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (2.3.3)
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       sprockets (>= 2.8, < 4.0)
     sqlite3 (1.3.11)
-    thor (0.19.1)
-    thread_safe (0.3.5)
-    tzinfo (0.3.49)
+    thor (0.19.4)
+    thread_safe (0.3.6)
+    tzinfo (1.2.3)
+      thread_safe (~> 0.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
+  active_model_serializers (= 0.10.4)
   paging_cursor!
-  rails (~> 4.0.0)
+  rails (~> 4.1.0)
   rspec
   rspec-rails
   sqlite3

lib/paging_cursor.rb

@@ -1,7 +1,7 @@
 module PagingCursor
 end
 
-
 require 'paging_cursor/config'
 require 'paging_cursor/direction'
 require 'paging_cursor/active_record'
+require 'paging_cursor/active_model_serializer'

lib/paging_cursor/active_model_serializer.rb

@@ -0,0 +1,49 @@
+require 'active_model_serializers'
+
+# See https://github.com/rails-api/active_model_serializers/blob/a032201a91cbca407211bca0392ba881eef1f7ba/lib/active_model/serializer/collection_serializer.rb
+# for original version
+module ActiveModel
+  class Serializer
+    class CollectionSerializer
+
+      def paginated?
+        ActiveModelSerializers.config.jsonapi_pagination_links_enabled &&
+        object.respond_to?(:cursor_before) &&
+        object.respond_to?(:cursor_after)
+      end
+    end
+  end
+end
+
+# See https://github.com/rails-api/active_model_serializers/blob/a032201a91cbca407211bca0392ba881eef1f7ba/lib/active_model_serializers/adapter/json_api/pagination_links.rb
+# for the original version
+module ActiveModelSerializers
+  module Adapter
+    class JsonApi < Base
+      class PaginationLinks
+
+        def as_json
+          pages_from.each_with_object({}) do |(key, value), hash|
+            params = query_parameters.merge(cursor: value)
+            params = Rack::Utils.build_nested_query(params)
+            hash[key] = "#{url(adapter_options)}?#{params}"
+          end
+        end
+
+        private
+
+        def pages_from
+          {}.tap do |pages|
+            return {} if collection.empty?
+
+            pages[:self] = { before: (collection.cursor_after + 1).to_s }
+            pages[:first] = { before: nil }
+            pages[:prev] = { after: collection.cursor_after.to_s }
+            pages[:next] = { before: collection.cursor_before.to_s }
+            pages[:last] = { after: nil }
+          end
+        end
+      end
+    end
+  end
+end

lib/paging_cursor/active_record.rb

@@ -79,7 +79,7 @@ def to_a
     # # support pagination on associations and scopes
     klasses.each do |klass| 
       klass.send(:prepend, SortedResults)
-      klass.send(:include, FinderMethods) 
+      klass.send(:include, FinderMethods)
       klass.send(:include, ::PagingCursor::Direction)
     end
   end

paging_cursor.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name        = 'paging_cursor'
-  s.version     = '0.1.0'
+  s.version     = '0.2.0'
   s.date        = '2016-04-23'
   s.summary     = "ActiveRecord and ActiveController extensions for cursor pagination"
   s.description = "ActiveRecord and ActiveController extensions for cursor pagination"
@@ -12,7 +12,8 @@ Gem::Specification.new do |s|
   s.files = Dir['{lib,spec}/**/*', 'README*', 'LICENSE*']
 
   s.add_development_dependency "rspec"
-  s.add_development_dependency "rails", "~> 4.0.0"
+  s.add_development_dependency "rails", "~> 4.1.0"
   s.add_development_dependency "sqlite3"
   s.add_development_dependency "rspec-rails"
+  s.add_development_dependency "active_model_serializers", "0.10.4"
 end

spec/active_model_serializer_spec.rb

@@ -0,0 +1,65 @@
+require 'rails_helper'
+include ActiveModelSerializers::Adapter
+
+describe JsonApi::PaginationLinks do
+
+  before do
+    10.times do
+      User.create
+    end
+    @per_page = 5
+  end
+
+  after do
+    User.delete_all
+  end
+
+  shared_examples_for 'it returns the correct links' do
+    specify do
+      serialized_object = User.cursor(before: cursor, limit: @per_page)
+      options = {
+        serialization_context: OpenStruct.new(
+          request_url: 'www.example.com',
+          query_parameters: {'user_id' => '7'} # arbitrary string
+        )
+      }
+
+      expected_links = {
+        first: 'www.example.com?user_id=7&cursor[before]',
+        last: 'www.example.com?user_id=7&cursor[after]',
+        next: "www.example.com?user_id=7&cursor[before]=#{cursor - @per_page}",
+        prev: "www.example.com?user_id=7&cursor[after]=#{cursor - 1}",
+        self: "www.example.com?user_id=7&cursor[before]=#{cursor}"
+      }
+
+      response_links = JsonApi::PaginationLinks.new(serialized_object, options).as_json
+      expect(response_links).to eq(expected_links)
+    end
+  end
+
+  context 'cursor is the max id of serialized collection' do
+    it_behaves_like 'it returns the correct links' do
+      let(:cursor) { 10 }
+    end
+  end
+
+  context 'cursor is less than the max id of serialized collection' do
+    it_behaves_like 'it returns the correct links' do
+      let(:cursor) { 18 }
+    end
+  end
+
+  context 'empty serialized object' do
+    it 'returns an empty links hash' do
+      serialized_object = User.cursor(before: 1)
+      options = {
+        serialization_context: OpenStruct.new(
+          request_url: 'www.example.com',
+          query_parameters: {'user_id' => '7'}
+        )
+      }
+      response_links = JsonApi::PaginationLinks.new(serialized_object, options).as_json
+      expect(response_links).to eq({})
+    end
+  end
+end

spec/active_record_spec.rb

@@ -36,7 +36,7 @@
     expect(Post.cursor(limit: 2).size).to eq(2)
   end
 
-  it 'accepts string and symbol eys' do
+  it 'accepts string and symbol keys' do
     expect(Post.cursor('limit' => 2)).to eq(Post.cursor(limit: 2))
   end