Populate the Total header

Signed-off-by: David Celis <me@davidcel.is>

Author: davidcelis

README.md

@@ -1,6 +1,6 @@
 # api-pagination [![Build Status](https://travis-ci.org/davidcelis/api-pagination.png)](https://travis-ci.org/davidcelis/api-pagination)
 
-Put pagination info in a Link header, not the response body.
+Paginate in your headers, not in your response body.
 
 ## Installation
 
@@ -72,7 +72,7 @@ class MoviesAPI < Grape::API
 end
 ```
 
-Then `curl --include` to see your Link header pagination in action:
+Then `curl --include` to see your header-based pagination in action:
 
 ```bash
 $ curl --include 'https://localhost:3000/movies?page=5'
@@ -81,6 +81,7 @@ Link: <http://localhost:3000/movies?page=1>; rel="first">,
   <http://localhost:3000/movies?page=173>; rel="last">,
   <http://localhost:3000/movies?page=6>; rel="next">,
   <http://localhost:3000/movies?page=4>; rel="prev">
+Total: 4321
 # ...
 ```
 

lib/api-pagination.rb

@@ -30,6 +30,13 @@ def pages_from(collection)
         end
       end
     end
+
+    def total_from(collection)
+      case ApiPagination.paginator
+        when :kaminari      then collection.total_count
+        when :will_paginate then collection.total_entries
+      end
+    end
   end
 end
 

lib/grape/pagination.rb

@@ -15,6 +15,7 @@ def paginate(collection)
             end
 
             header 'Link', links.join(', ') unless links.empty?
+            header 'Total', ApiPagination.total_from(collection)
           end
 
           ApiPagination.paginate(collection, params, &block)

lib/rails/pagination.rb

@@ -15,7 +15,8 @@ def paginate(collection)
             links << %(<#{url}?#{new_params.to_param}>; rel="#{k}")
           end
 
-          headers['Link'] = links.join(', ') unless links.empty?
+          headers['Link']  = links.join(', ') unless links.empty?
+          headers['Total'] = ApiPagination.total_from(collection)
         end
 
         ApiPagination.paginate(collection, params, &block)

spec/grape_spec.rb

@@ -7,12 +7,18 @@
 describe NumbersAPI do
   describe 'GET #index' do
     let(:links) { last_response.headers['Link'].split(', ') }
+    let(:total) { last_response.headers['Total'].to_i }
 
     context 'without enough items to give more than one page' do
+      before { get :numbers, :count => 20 }
+
       it 'should not paginate' do
-        get :numbers, :count => 20
         expect(last_response.headers.keys).not_to include('Link')
       end
+
+      it 'should give a Total header' do
+        expect(total).to eq(20)
+      end
     end
 
     context 'with existing Link headers' do

spec/rails_spec.rb

@@ -6,14 +6,20 @@
 
 describe NumbersController, :type => :controller do
   before { request.host = 'example.org' }
+
   describe 'GET #index' do
     let(:links) { response.headers['Link'].split(', ') }
+    let(:total) { response.headers['Total'].to_i }
 
     context 'without enough items to give more than one page' do
+      before { get :index, :count => 20 }
       it 'should not paginate' do
-        get :index, :count => 20
         expect(response.headers.keys).not_to include('Link')
       end
+
+      it 'should give a Total header' do
+        expect(total).to eq(20)
+      end
     end
 
     context 'with existing Link headers' do

spec/spec_helper.rb

@@ -24,6 +24,8 @@ def per(per)
   def paginate(options = {})
     page(options[:page]).per(options[:per_page])
   end
+
+  alias :total_entries :total_count
 end
 
 if ENV['PAGINATOR']

spec/support/shared_examples/existing_headers.rb

@@ -7,4 +7,8 @@
     expect(links).to include('<http://example.org/numbers?count=30&page=2&with_headers=true>; rel="next"')
     expect(links).to include('<http://example.org/numbers?count=30&page=2&with_headers=true>; rel="last"')
   end
+
+  it 'should give a Total header' do
+    expect(total).to eq(30)
+  end
 end

spec/support/shared_examples/first_page.rb

@@ -14,4 +14,8 @@
   it 'should give a link with rel "next"' do
     expect(links).to include('<http://example.org/numbers?count=100&page=2>; rel="next"')
   end
+
+  it 'should give a Total header' do
+    expect(total).to eq(100)
+  end
 end

spec/support/shared_examples/last_page.rb

@@ -14,4 +14,8 @@
   it 'should give a link with rel "prev"' do
     expect(links).to include('<http://example.org/numbers?count=100&page=3>; rel="prev"')
   end
+
+  it 'should give a Total header' do
+    expect(total).to eq(100)
+  end
 end