Feature/total pages

lib/mongoid/pagination.rb

@@ -5,6 +5,7 @@ module Pagination
     extend ActiveSupport::Concern
 
     module ClassMethods
+      DEFAULT_PAGE_LIMIT = 25
 
       # Paginate the results
       #
@@ -16,7 +17,7 @@ module ClassMethods
       def paginate(opts = {})
         return criteria if opts[:limit].blank? and opts[:page].blank? and opts[:offset].blank?
 
-        limit = (opts[:limit] || 25).to_i
+        limit = (opts[:limit] || DEFAULT_PAGE_LIMIT).to_i
         page  = (opts[:page]  || 1).to_i
 
         if opts[:page].blank?
@@ -36,9 +37,17 @@ def paginate(opts = {})
       #
       # @param [Integer] page_limit the max number of results to return
       # @return [Mongoid::Criteria]
-      def per_page(page_limit = 25)
+      def per_page(page_limit = DEFAULT_PAGE_LIMIT)
         limit(page_limit.to_i)
       end
+
+      # Calculate total number of pages
+      #
+      # @return [Integer] total documents in collection divided by limit
+      def total_pages
+        limit = criteria.options[:limit] || DEFAULT_PAGE_LIMIT
+        (criteria.count / limit) + (criteria.count % limit)
+      end
     end
   end
 end

mongoid-pagination.gemspec

@@ -21,4 +21,5 @@ Gem::Specification.new do |s|
 
   s.add_dependency 'mongoid'
   s.add_dependency 'activesupport'
+  s.add_development_dependency 'pry'
 end

spec/config/mongoid.yml

@@ -0,0 +1,6 @@
+test:
+  clients:
+    default:
+      database: mongoid_pagination_test
+      hosts:
+        - localhost:27017

spec/pagination_spec.rb

@@ -1,4 +1,5 @@
 require 'spec_helper'
+require 'pry'
 
 describe Mongoid::Pagination do
   class Person
@@ -161,4 +162,28 @@ class Person
       Person.per_page.options[:limit].should == 25
     end
   end
+
+  describe ".total_pages" do
+    subject { Person.paginate(:limit => 2) }
+
+    context "an even number of records" do
+      before do
+        8.times { Person.create! }
+      end
+
+      it "calculates the total number of pages" do
+        expect(subject.total_pages).to eq 4
+      end
+    end
+
+    context "an odd number of records" do
+      before do
+        7.times { Person.create! }
+      end
+
+      it "calculates the total number of pages" do
+        expect(subject.total_pages).to eq 4
+      end
+    end
+  end
 end

spec/spec_helper.rb

@@ -1,16 +1,15 @@
 require 'rubygems'
 require 'bundler'
-
 Bundler.setup :default, :test
 Bundler.require :default, :test
 
 $:.push(File.expand_path(File.dirname(__FILE__)))
 require './lib/mongoid-pagination'
 
-Mongoid.database = Mongo::Connection.new.db('mongoid-pagination_test')
+Mongoid.load!('./spec/config/mongoid.yml', 'test')
 
-RSpec.configure do |c|
-  c.before(:each) do
-    Mongoid.database.collections.each { |c| c.drop unless c.name =~ /system\.indexes$/}
+RSpec.configure do |config|
+  config.before(:each) do
+    Mongoid.purge!
   end
-end
+end