CarrierWave：图像未显示在显示页面错误：帖子中的 NoMethodError#show

Question

我正在尝试使用带有 Ruby on Rails 的 Carrierwave gem 在我的应用程序中显示图像。我正在使用 Carrierwave 支持的多图像上传选项。一切工作正常，除了当我转到显示页面时出现此错误：NoMethodError in Posts#show

这是代码

我的 show.html.erb 页面

<p id="notice"><%= notice %></p>

<%= image_tag @post.image.url %>

<p>
  <strong>Name:</strong>
  <%= @post.name %>
</p>

<%= link_to 'Edit', edit_post_path(@post) %> |
<%= link_to 'Back', posts_path %>

_form.html.erb

<%= form_for(@post , html: { multipart: true }) do |f| %>
  <% if @post.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@post.errors.count, "error") %> prohibited this post from being saved:</h2>

      <ul>
      <% @post.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>

  <div class="field">
    <%= f.label :image %><br>
    <%= f.file_field :image , multiple: true %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

post_controller.rb

class PostsController < ApplicationController
  before_action :set_post, only: [:show, :edit, :update, :destroy]

  # GET /posts
  # GET /posts.json
  def index
    @posts = Post.all
  end

  # GET /posts/1
  # GET /posts/1.json
  def show
  end

  # GET /posts/new
  def new
    @post = Post.new
  end

  # GET /posts/1/edit
  def edit
  end

  # POST /posts
  # POST /posts.json
  def create
    @post = Post.new(post_params)

    respond_to do |format|
      if @post.save
        format.html { redirect_to @post, notice: 'Post was successfully created.' }
        format.json { render :show, status: :created, location: @post }
      else
        format.html { render :new }
        format.json { render json: @post.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /posts/1
  # PATCH/PUT /posts/1.json
  def update
    respond_to do |format|
      if @post.update(post_params)
        format.html { redirect_to @post, notice: 'Post was successfully updated.' }
        format.json { render :show, status: :ok, location: @post }
      else
        format.html { render :edit }
        format.json { render json: @post.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /posts/1
  # DELETE /posts/1.json
  def destroy
    @post.destroy
    respond_to do |format|
      format.html { redirect_to posts_url, notice: 'Post was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_post
      @post = Post.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def post_params
      params.require(:post).permit(:name, {image:[]})
    end
end

模型 post.rb

class Post < ActiveRecord::Base
  mount_uploaders :image, ImageUploader

end

Answer 1

在您的 post_params 中，您已将图像参数定义为数组

params.require(:post).permit(:name, {image:[]})

您应该使用迭代从该数组中检索图像：

<% @post.image.each do |image| %>
    <%= image_tag image.url %>
<% end %>

这将显示此帖子上发布的所有图像 或者，如果您只想为帖子保存一张图片，请更改

params.require(:post).permit(:name, {image:[]})

到

params.require(:post).permit(:name, :image)

一切都会好起来的！

注意：

<%= image_tag @post.image[0].url %>

也适用于您编写的代码，因为它只会获取该图像数组中第一张图像的 url