使用Mongoid实现ROR分页时total_pages方法未定义问题求助

Let's break down why you're hitting this error and how to fix it step by step:

The Root Cause #

Your current controller code only calls per_page(10) without specifying a page number via the page() method. The mongoid-pagination gem requires both methods to be chained onto your query to generate a paginated collection that includes the necessary metadata (like total_pages) that the paginate helper relies on.

Step 1: Update Your Controller Code #

Modify your controller to include the page() method, which uses the params[:page] value from the request (this defaults to page 1 if no parameter is provided):

@services = Service.where(active: true).page(params[:page]).per_page(10)

Step 2: Verify Gem Setup #

Double-check that you've properly set up the gem:

• Ensure gem 'mongoid-pagination' is added to your Gemfile
• Run bundle install if you haven't already
• Restart your Rails server to make sure the gem loads correctly

Bonus: Compatibility Note #

If you're using a newer version of Mongoid (7.x+), keep in mind that mongoid-pagination hasn't been updated in quite some time. If you still run into issues after the above fix, consider switching to actively maintained alternatives like kaminari-mongoid or will_paginate-mongoid—they offer similar functionality with better support for modern Mongoid versions.

Test the Fix #

After updating the controller code, reload your index page. The paginate helper should now have access to the total_pages method and render pagination links correctly.

内容的提问来源于stack exchange，提问作者Carlos lima