I have a Photo Share web app and I am trying to add comments in photos. I can't spot any mistakes. Maybe in the controller class in index function is the problem. There is an undefined method error when I try to show-post comments below the photo. Error in HAML code.

Error: - if @photo_comments.any?

Controller:

class CommentsController < ApplicationController

  def index
    @photo_comments = Comment.where(photo_id: => photo_id)
  end

  def create
    @comment = Comment.create(user_id: params[:user_id], photo_id: params[:photo_id], text: params[:comment][:text])
    flash[:notice] = "Successfully added a comment"
    redirect_to :back
  end

  private
    def comment_params
      params.require(:comment).permit(:user_id, :photo_id, :text)
    end

end

Model:

class Comment < ActiveRecord::Base
    belongs_to :user
    belongs_to :photo
end

Database:

class CreateComments < ActiveRecord::Migration
  def change
    create_table :comments do |t|
      t.integer :user_id
      t.integer :photo_id
      t.string :text
      t.timestamps
    end
  end
end

View:

%p Comments
- if @photo_comments.any?
  - @photo_comments.each do |comment|
    .bold-text= "#{comment.user.email}: "
    .normal-text= comment.text
    %br
- else
  .text No comments for this photo yet! 
%br
%br
%p
  = form_for Comment.new(), :url => user_photo_comments_path do |form|
    = form.label :text, 'Add a Comment'
    %br
    = form.text_area :text
    %br
    = form.submit 'Post'

Routes:

Rails.application.routes.draw do
  get '/' => 'home#index'
  resources :users do
    resources :photos do
      resources :comments
    end
    resources :follows
  end

  resources :tags, only: [:create, :destroy]
  get '/log-in' => "sessions#new"
  post '/log-in' => "sessions#create"
  get '/log-out' => "sessions#destroy", as: :log_out

end

CodePudding user response：

These two line make no sense:

- if @photo_comments.nil?
  - @photo_comments.each do |comment|

If the instance variable @photo_comments is nil then iterate of it? Of course, you will get an undefined method 'each' for nil:NilClass in that case.

I guess you mean something like this:

- unless @photo_comments.nil?
  - @photo_comments.each do |comment|

CodePudding user response：

This line seems a bit problematic:

@photo_comments = Comment.where(photo_id: => photo_id)

I can spot a couple of potential errors here:

• hash syntax: you are mixing both styles, you should use photo_id: photo_id or (Ruby pre 1.9) :photo_id => photo_id
• the method or variable photo_id seems not defined in that controller, maybe you would mean params[:photo_id]?

CodePudding user response：

There is definitely a syntax error on this line:

@photo_comments = Comment.where(photo_id: => photo_id)

also photo_id is not defined anywhere in the controller so maybe it should instead look like:

@photo_comments = Comment.where(photo_id: params[:photo_id])

?

The error undefined_method often comes when calling a method on a nil value. In your case instance variable @photo_comments is nil thus giving you undefined_method error in views.