Add option to configure the cursor/param name

README.md

@@ -103,5 +103,25 @@ new comments are posted, as the cache key instead.
 When a controller action sets an ETag and uses geared pagination, the current page and gear ratios are
 automatically included in the ETag.
 
+
+## Configuration
+
+The `cursor_name` configuration option determines the name of the query parameter used for pagination cursors in the URLs generated by Geared Pagination. By default, the `cursor_name` is set to `:page`.
+
+If you want to use a different query parameter name for the pagination cursor, you can set the `cursor_name` configuration option to a different value:
+
+```ruby
+GearedPagination.configure do |config|
+  config.cursor_name = :cursor
+end
+```
+
+Creating links is now possible using the cursor parameter:
+
+```ruby
+<%= link_to "Next page", messages_path(cursor: @page.next_param) %>
+```
+
+
 ## License
 Geared Pagination is released under the [MIT License](https://opensource.org/licenses/MIT).

lib/geared_pagination/controller.rb

@@ -29,7 +29,11 @@ def geared_page?
       end
 
       def current_page_param
-        params[:page]
+        params[page_param_name]
+      end
+
+      def page_param_name
+        GearedPagination.config.cursor_name
       end
   end
 end

lib/geared_pagination/engine.rb

@@ -1,10 +1,28 @@
+require 'singleton'
 require 'rails/engine'
 require 'geared_pagination/controller'
 
-class GearedPagination::Engine < ::Rails::Engine
-  initializer :geared_pagination do |app|
-    ActiveSupport.on_load :action_controller do
-      ActionController::Base.send :include, GearedPagination::Controller
+module GearedPagination
+  class << self
+    def configure
+      yield config
+    end
+
+    def config
+      @_config ||= Configuration.new
+    end
+  end
+
+  class Configuration
+    include ActiveSupport::Configurable
+    config_accessor :cursor_name, default: :page
+  end
+
+  class Engine < ::Rails::Engine
+    initializer :geared_pagination do |app|
+      ActiveSupport.on_load :action_controller do
+        ActionController::Base.send :include, GearedPagination::Controller
+      end
     end
   end
 end

lib/geared_pagination/headers.rb

@@ -35,8 +35,12 @@ def link_header(rel:, page:)
 
       def uri(page:)
         Addressable::URI.parse(request.url).tap do |uri|
-          uri.query_values = (uri.query_values || {}).merge("page" => page)
+          uri.query_values = (uri.query_values || {}).merge("#{cursor_name}".to_sym => page)
         end.to_s
       end
+
+      def cursor_name
+        GearedPagination.config.cursor_name
+      end
   end
 end

test/cursor_name_test.rb

@@ -0,0 +1,59 @@
+require 'test_helper'
+require 'active_support/core_ext/string/inquiry'
+require 'geared_pagination/headers'
+require 'geared_pagination/recordset'
+
+class GearedPagination::HeadersTest < ActiveSupport::TestCase
+  Request    = Struct.new(:url, :format)
+  Controller = Struct.new(:request, :headers)
+
+  setup do
+    create_recordings
+
+    @controller_serving_json = Controller.new(Request.new("http://example.com/recordset.json", "json".inquiry), {})
+    @controller_serving_html = Controller.new(Request.new("http://example.com/recordset", "html".inquiry), {})
+
+    @single_page_recordset = GearedPagination::Recordset.new(Recording.all, per_page: 1000)
+    @many_page_recordset   = GearedPagination::Recordset.new(Recording.all, per_page: 1)
+  end
+
+  test "total count with custom cursor name" do
+    GearedPagination::Headers.new(page: @many_page_recordset.page(1), controller: @controller_serving_json).apply
+    assert_equal Recording.all.count.to_s, @controller_serving_json.headers["X-Total-Count"]
+  end
+
+  test "no link for html requests with custom cursor name" do
+    GearedPagination::Headers.new(page: @many_page_recordset.page(1), controller: @controller_serving_html).apply
+    assert @controller_serving_html.headers["Link"].nil?
+  end
+
+  test "no link for json request with single page with custom cursor name" do
+    GearedPagination::Headers.new(page: @single_page_recordset.page(1), controller: @controller_serving_json).apply
+    assert @controller_serving_html.headers["Link"].nil?
+  end
+
+  test "links for json request with multiple pages with custom cursor name" do
+    begin
+      GearedPagination.configure do |config|
+        config.cursor_name = :cursor
+      end
+
+      GearedPagination::Headers.new(page: @many_page_recordset.page(1), controller: @controller_serving_json).apply
+      assert_equal '<http://example.com/recordset.json?cursor=2>; rel="next"',
+        @controller_serving_json.headers["Link"]
+
+      GearedPagination::Headers.new(page: @many_page_recordset.page(2), controller: @controller_serving_json).apply
+      assert_equal '<http://example.com/recordset.json?cursor=3>; rel="next"',
+        @controller_serving_json.headers["Link"]
+    ensure
+      GearedPagination.configure do |config|
+        config.cursor_name = :page
+      end
+    end
+  end
+
+  test "no link for json request with multiple pages on last page with custom cursor name" do
+    GearedPagination::Headers.new(page: @many_page_recordset.page(Recording.all.count), controller: @controller_serving_json).apply
+    assert @controller_serving_json.headers["Link"].nil?
+  end
+end