Rails 5刷新Partial中Div报错：FormsController#show模板未找到

Hey there, let's break down what's going on here and fix that error you're seeing:

• Your testzzz.html.erb works because it's a full template that directly renders _test_partial.html.erb during a normal page load—Rails doesn't need a special controller action to handle that straightforward render.
• When you try to refresh the partial via AJAX, Rails defaults to routing that request to FormsController#show (a common fallback for RESTful setups), but you don't have a template for that action, and you haven't set up a dedicated route/action to handle the partial refresh specifically.

Here's how to fix this step by step:

1. Add a Route for the Partial Refresh #

First, tell Rails exactly where to send the AJAX request. Open your config/routes.rb and add one of these options based on your needs:

# For refreshing a partial tied to a specific form (member route)
resources :forms do
  get 'refresh_partial', on: :member
end

# OR for a general partial not linked to a single form (collection route)
resources :forms do
  get 'refresh_partial', on: :collection
end

# OR a simple standalone route (if you don't need RESTful context)
get 'forms/refresh_partial', to: 'forms#refresh_partial'

2. Add the Controller Action #

Next, create the refresh_partial action in app/controllers/forms_controller.rb to handle the request and return your updated partial. You have two solid options here:

Option 1: Render the Partial Directly (Returns Raw HTML) #

This is great if you want to handle the DOM update in your frontend JS:

def refresh_partial
  # Define any variables your partial needs (like the time/random number)
  @current_time = Time.now
  @random_number = rand(100)

  # Render only the partial, no surrounding layout
  render partial: 'test_partial', layout: false
end

Option 2: Use a Rails JS Template (Handles DOM Updates Automatically) #

If you prefer to let Rails handle the DOM replacement:

def refresh_partial
  @current_time = Time.now
  @random_number = rand(100)
  
  respond_to do |format|
    format.js # This will look for app/views/forms/refresh_partial.js.erb
  end
end

Then create app/views/forms/refresh_partial.js.erb with this code to update your div:

// Replace 'your-target-div-id' with the actual ID of the div holding your partial
$('#your-target-div-id').html("<%= j render partial: 'test_partial' %>");

The j is shorthand for escape_javascript—it makes sure your partial's HTML is safely inserted into the JS without breaking things.

3. Update Your Frontend AJAX Request #

Make sure your JS points to the correct route. For example, if you used a member route (tied to a specific form):

$('#refresh-button').on('click', function() {
  $.ajax({
    url: '/forms/<%= @form.id %>/refresh_partial', // Match the route you set up
    type: 'GET',
    success: function(data) {
      // If you used Option 1, replace the div content here
      $('#your-target-div-id').html(data);
      // If you used Option 2, the JS template handles this automatically
    }
  });
});

Quick Pitfalls to Avoid #

• Double-check your partial path: If _test_partial.html.erb lives in app/views/shared, you'll need to write render partial: 'shared/test_partial' instead of just 'test_partial'.
• If you use Rails UJS, you can skip custom JS entirely by using link_to 'Refresh', form_refresh_partial_path(@form), remote: true.
• Don't forget any authorization rules (like before_action :authenticate_user! if using Devise) if your app requires them for this action.

内容的提问来源于stack exchange，提问作者Chris Mendla