ActionView::Template::Error (undefined method `comment_cflags_path' for #<#<Class:0x007f423040d570>:0x007f42300dd170>

Question

I have a very basic Photo and Comment model that works and then I have a built a Cflag model that is used to flag comments. I am getting the following error from Heroku log when I visit the photos/show.html.erb view:

ActionView::Template::Error (undefined method `comment_cflags_path' for #<#:0x007f42300dd170>

Show:

photos/show.html.erb
.
<% @photo.comments.each do |comment| %>
  <%= form_for([comment, Cflag.new]) do |f| %>
    <%= f.hidden_field :user_id, value: current_user.id %>
    <%= f.submit "Report Inappropiate" %>
  <% end %>
<% end %> 

Routes:

resources :photos do
  resources :comments do
    resources :cflags
  end
end

Rails routes:

    photo_comment_cflags GET        /photos/:photo_id/comments/:comment_id/cflags(.:format)          cflags#index
                         POST       /photos/:photo_id/comments/:comment_id/cflags(.:format)          cflags#create
 new_photo_comment_cflag GET        /photos/:photo_id/comments/:comment_id/cflags/new(.:format)      cflags#new
edit_photo_comment_cflag GET        /photos/:photo_id/comments/:comment_id/cflags/:id/edit(.:format) cflags#edit
     photo_comment_cflag GET        /photos/:photo_id/comments/:comment_id/cflags/:id(.:format)      cflags#show
                         PATCH      /photos/:photo_id/comments/:comment_id/cflags/:id(.:format)      cflags#update
                         PUT        /photos/:photo_id/comments/:comment_id/cflags/:id(.:format)      cflags#update
                         DELETE     /photos/:photo_id/comments/:comment_id/cflags/:id(.:format)      cflags#destroy
PhotosController
def show
  @photo = Photo.approved.find(params[:id])
end

Photo Controller:

def create
   @photo = Photo.find(params[:photo_id])
   @comment = @photo.comments.build(comment_params)
   @comment.save
   respond_to do |format|
     format.html { redirect_to :back }
     format.js 
   end 
end   

Cflag Model:

class Cflag < ActiveRecord::Base
  belongs_to :comment, counter_cache: true
  belongs_to :user, counter_cache: true
  validates :user_id, presence: true 
  validates :comment_id, presence: true
  validates :user_id, uniqueness: { 
    scope: [:comment_id],
    message: 'You can only flag a comment once. Thank you for your feedback.'
  }
  default_scope -> { order(created_at: :desc) }
end

Cflags controller:

class CflagsController < ApplicationController
before_action :logged_in_user

def new
end

def create
  @comment = Comment.find(params[:comment_id])
  @cflag = @comment.cflags.build(cflag_params)
    if @cflag.save
      if @comment.cflags_count > 1
        @comment.update_attribute(:approved, false)  
        flash[:success] = "Flag created! Comment ##{@comment.id} has been removed for review. Thank you for your feedback"
        redirect_to :back
      else    
        flash[:success] = "Flag created! Thank you for your feedback"
        redirect_to :back
      end
    else
      redirect_to :back, notice: @cflag.errors.full_messages  
    end    
  end    

  private 
    def cflag_params
      params.require(:cflag).permit(:user_id, :comment_id).merge(user_id: current_user.id)
    end
end

Schema:

create_table "cflags", force: :cascade do |t|
  t.integer  "comment_id"
  t.integer  "user_id"
  t.datetime "created_at", null: false
  t.datetime "updated_at", null: false
end

add_index "cflags", ["comment_id"], name: "index_cflags_on_comment_id"
add_index "cflags", ["user_id"], name: "index_cflags_on_user_id"

I changed the form to:

<% @photo.comments.each do |comment| %>
  <%= form_for([comment, url: photo_comment_cflags_path]) do |f| %>
    <%= f.hidden_field :user_id, value: current_user.id %>
    <%= f.submit "Report Inappropiate" %>
  <% end %>
<% end %>

And got the following error from Heroku:

ActionView::Template::Error (No route matches {:action=>"index", :controller=>"cflags", :id=>"100"} missing required keys: [:comment_id, :photo_id]):

Answer 1

Look at your routes:

/photos/:photo_id/comments/:comment_id/cflags(.:format)          

Your path need also a photo_id.

You are missing the @photo in your form_for. Just change the form_for to:

<%= form_for([@photo, comment, Cflag.new]) do |f| %>