Ruby on Rails：为Recipeazy食谱网站添加可编辑删除的评论功能

Great question! Let’s break this down—first, about that tutorial: it’s focused on building a JSON API, so if your Recipeazy app is a traditional server-rendered Rails app (not API-only), some parts (like handling JSON responses instead of views) won’t directly apply. But the core concepts (associations, CRUD actions for comments) are totally transferable. Let’s walk through how to implement this for a standard Rails app:

Step 1: Set Up the Comment Model #

First, generate a Comment model that belongs to both a User and a Recipe (since each comment is tied to a user and a recipe):

rails generate model Comment content:text user:references recipe:references
rails db:migrate

Then update your models to define the associations:

• In app/models/user.rb:

  class User < ApplicationRecord
    has_many :comments, dependent: :destroy
    # ... your existing code
  end
  

• In app/models/recipe.rb:

  class Recipe < ApplicationRecord
    has_many :comments, dependent: :destroy
    # ... your existing code
  end
  

• In app/models/comment.rb:

  class Comment < ApplicationRecord
    belongs_to :user
    belongs_to :recipe
    validates :content, presence: true
  end
  

Step 2: Add Nested Routes #

Since comments are a resource under recipes, nest them in your config/routes.rb:

Rails.application.routes.draw do
  resources :recipes do
    resources :comments, only: [:create, :edit, :update, :destroy]
  end
  # ... your existing routes
end

This gives you paths like /recipes/:recipe_id/comments for creating, and /recipes/:recipe_id/comments/:id/edit for editing.

Step 3: Build the Comments Controller #

Create app/controllers/comments_controller.rb with actions for creating, editing, updating, and destroying—plus authorization checks to ensure only the comment’s owner can edit/delete:

class CommentsController < ApplicationController
  before_action :set_recipe
  before_action :set_comment, only: [:edit, :update, :destroy]
  before_action :authorize_owner!, only: [:edit, :update, :destroy]

  def create
    @comment = @recipe.comments.build(comment_params.merge(user: current_user))
    if @comment.save
      redirect_to @recipe, notice: 'Comment added successfully!'
    else
      redirect_to @recipe, alert: 'Failed to add comment.'
    end
  end

  def edit
  end

  def update
    if @comment.update(comment_params)
      redirect_to @recipe, notice: 'Comment updated successfully!'
    else
      render :edit
    end
  end

  def destroy
    @comment.destroy
    redirect_to @recipe, notice: 'Comment deleted.'
  end

  private

  def set_recipe
    @recipe = Recipe.find(params[:recipe_id])
  end

  def set_comment
    @comment = @recipe.comments.find(params[:id])
  end

  def comment_params
    params.require(:comment).permit(:content)
  end

  def authorize_owner!
    unless @comment.user == current_user
      redirect_to @recipe, alert: 'You can only edit or delete your own comments.'
    end
  end
end

Note: This assumes you have a current_user method set up (from Devise or your own authentication system).

Step 4: Add Comment UI to Recipe Views #

Update your recipe show view (app/views/recipes/show.html.erb) to display comments and add a form for new comments:

<!-- Display existing comments -->
<h3>Comments</h3>
<% @recipe.comments.each do |comment| %>
  <div class="comment">
    <p><strong><%= comment.user.name %></strong></p>
    <p><%= comment.content %></p>
    <% if comment.user == current_user %>
      <%= link_to 'Edit', edit_recipe_comment_path(@recipe, comment) %>
      <%= link_to 'Delete', recipe_comment_path(@recipe, comment), method: :delete, data: { confirm: 'Are you sure?' } %>
    <% end %>
  </div>
<% end %>

<!-- Form to add a new comment -->
<% if current_user %>
  <%= form_with(model: [@recipe, @recipe.comments.build], local: true) do |form| %>
    <div class="field">
      <%= form.label :content %>
      <%= form.text_area :content %>
    </div>
    <div class="actions">
      <%= form.submit 'Add Comment' %>
    </div>
  <% end %>
<% else %>
  <p>Please <%= link_to 'log in', new_user_session_path %> to leave a comment.</p>
<% end %>

Step 5: Add Edit View for Comments #

Create app/views/comments/edit.html.erb for the edit form:

<h3>Edit Comment</h3>
<%= form_with(model: [@recipe, @comment], local: true) do |form| %>
  <div class="field">
    <%= form.label :content %>
    <%= form.text_area :content %>
  </div>
  <div class="actions">
    <%= form.submit 'Update Comment' %>
    <%= link_to 'Cancel', @recipe %>
  </div>
<% end %>

Optional: Use a Authorization Gem #

For more complex authorization rules (instead of the simple check in the controller), consider using gems like Pundit or CanCanCan—they make managing permissions cleaner as your app grows.

If you run into specific issues (like authentication problems, routing errors, or view rendering bugs), sharing snippets of your existing models/controllers/views would help narrow things down!

内容的提问来源于stack exchange，提问作者iiRosie1