Add support for optional param names

.gitignore

@@ -4,6 +4,7 @@
 .config
 .yardoc
 .ruby-version
+.ruby-gemset
 Gemfile.lock
 InstalledFiles
 _yardoc

README.md

@@ -40,8 +40,22 @@ ApiPagination.configure do |config|
   # By default, this is set to 'Per-Page'
   config.per_page_header = 'X-Per-Page'
 
-  # Optional : set this to add a header with the current page number.
+  # Optional: set this to add a header with the current page number.
   config.page_header = 'X-Page'
+
+  # Optional: what parameter should be used to set the page option
+  config.page_param = :page
+  # or
+  config.page_param do |params|
+    params[:page][:number]
+  end
+
+  # Optional: what parameter should be used to set the per page option
+  config.per_page_param = :per_page
+  # or
+  config.per_page_param do |params|
+    params[:page][:size]
+  end
 end
 ```
 

lib/api-pagination/configuration.rb

@@ -19,6 +19,33 @@ def initialize
       @include_total   = true
     end
 
+    ['page', 'per_page'].each do |param_name|
+      method_name = "#{param_name}_param"
+      instance_variable_name = "@#{method_name}"
+
+      define_method method_name do |params = nil, &block|
+        if block.is_a?(Proc)
+          instance_variable_set(instance_variable_name, block)
+          return
+        end
+
+        if instance_variable_get(instance_variable_name).nil?
+          # use :page & :per_page by default
+          instance_variable_set(instance_variable_name, (lambda { |p| p[param_name.to_sym] }))
+        end
+
+        instance_variable_get(instance_variable_name).call(params)
+      end
+
+      define_method "#{method_name}=" do |param|
+        if param.is_a?(Symbol) || param.is_a?(String)
+          instance_variable_set(instance_variable_name, (lambda { |params| params[param] }))
+        else
+          raise ArgumentError, "Cannot set page_param option"
+        end
+      end
+    end
+
     def paginator
       @paginator || set_paginator
     end

lib/grape/pagination.rb

@@ -3,9 +3,10 @@ module Pagination
     def self.included(base)
       Grape::Endpoint.class_eval do
         def paginate(collection)
-          per_page = params[:per_page] || route_setting(:per_page)
+          per_page = ApiPagination.config.per_page_param(params) || route_setting(:per_page)
+
           options = {
-            :page     => params[:page],
+            :page     => ApiPagination.config.page_param(params),
             :per_page => [per_page, route_setting(:max_per_page)].compact.min
           }
           collection = ApiPagination.paginate(collection, options)

lib/rails/pagination.rb

@@ -25,8 +25,11 @@ def paginate_with(collection)
 
     def _paginate_collection(collection, options={})
       options = {
-        :page     => params[:page],
-        :per_page => (options.delete(:per_page) || params[:per_page])
+        :page     => ApiPagination.config.page_param(params),
+        :per_page => (
+          options.delete(:per_page) ||
+          ApiPagination.config.per_page_param(params)
+        )
       }
       collection = ApiPagination.paginate(collection, options)
 

spec/rails_spec.rb

@@ -123,5 +123,82 @@
 
       after { ApiPagination.config.include_total = true }
     end
+
+    context 'custom page param' do
+      context 'page_param as a symbol' do
+        before do
+          ApiPagination.config.page_param = :foo
+          ApiPagination.config.page_header = 'Page'
+        end
+
+        after do
+          ApiPagination.config.page_param = :page
+          ApiPagination.config.page_header = nil
+        end
+
+        it 'should work' do
+          get :index, :foo => 2, :count => 100
+
+          expect(response.header['Page']).to eq('2')
+        end
+      end
+
+      context 'page_param as a block' do
+        before do
+          ApiPagination.config.page_param do |params|
+            params[:foo][:bar]
+          end
+
+          ApiPagination.config.page_header = 'Page'
+        end
+
+        after do
+          ApiPagination.config.page_param = :page
+          ApiPagination.config.page_header = nil
+        end
+
+        it 'should work' do
+          get :index, :foo => { :bar => 2 }, :count => 100
+
+          expect(response.header['Page']).to eq('2')
+        end
+      end
+    end
+
+    context 'custom per_page param' do
+      context 'per_page_param as a symbol' do
+        before do
+          ApiPagination.config.per_page_param = :foo
+        end
+
+        after do
+          ApiPagination.config.per_page_param = :per_page
+        end
+
+        it 'should work' do
+          get :index_with_no_per_page, :foo => 2, :count => 100
+
+          expect(response.header['Per-Page']).to eq('2')
+        end
+      end
+
+      context 'page_param as a block' do
+        before do
+          ApiPagination.config.per_page_param do |params|
+            params[:foo][:bar]
+          end
+        end
+
+        after do
+          ApiPagination.config.per_page_param = :per_page
+        end
+
+        it 'should work' do
+          get :index_with_no_per_page, :foo => { :bar => 2 }, :count => 100
+
+          expect(response.header['Per-Page']).to eq('2')
+        end
+      end
+    end
   end
 end

spec/support/numbers_controller.rb

@@ -41,6 +41,7 @@ def teardown(*methods)
 Rails.application.routes.draw do
   resources :numbers, :only => [:index] do
     get :index_with_custom_render, on: :collection
+    get :index_with_no_per_page,   on: :collection
   end
 end
 
@@ -76,4 +77,12 @@ def index_with_custom_render
 
     render json: NumbersSerializer.new(numbers)
   end
+
+  def index_with_no_per_page
+    total   = params.fetch(:count).to_i
+    numbers = (1..total).to_a
+    numbers = paginate numbers
+
+    render json: NumbersSerializer.new(numbers)
+  end
 end