在保存模型之前更新Rails

Question

以下是我的控制器方法部分：

class ProductAttachmentsController < ApplicationController

def create
    @product_attachment = ProductAttachment.new(product_attachment_params)
    session[:product_id] --> return product_id
    respond_to do |format|
      if @product_attachment.save

        format.html { redirect_to @product_attachment, notice: 'Product attachment was successfully created.' }
        # format.json { render :show, status: :created, location: @product_attachment }
        format.json {render :json => @product_attachment}
      else
        format.html { render :new }
        format.json { render json: @product_attachment.errors, status: :unprocessable_entity }
      end
    end
  end

end

模型关系：

class Product < ActiveRecord::Base
has_many :product_attachments, dependent: :destroy

end

class ProductAttachment < ActiveRecord::Base

    mount_uploader :attachment, AttachmentUploader
    belongs_to :product
end

用户上传图片后，product_attachments在表格中插入新行，现在如何将product_id与附件一起包含？

谢谢！

修改

查看表单：

<section class="photos-section <%= 'hide' unless @show_section == 'photo' %>">
    <%= form_for(@product) do |f| %>
        <div class="row">
            <div class="col-xs-12 col-sm-12 col-lg-12">
                <hr>
                <div class="form-group">
                    <div class="fileUpload btn btn-large btn-upload">
                        <span><i class="fa fa-upload" aria-hidden="true" id="file_upload"></i> Add Photos</span>
                        <input name="file_attachment" type="file" id="file_upload" class="upload">

                    </div>
                </div>
                <hr>

            </div>
        </div>
        <div class="row attachments-container">
        <div class="row">
  <div class="col-4 row-space-2 h5 invisible" id="js-first-photo-text">
    Your first photo appears in search results!
  </div>
</div>
            <% if !@product.new_record? %>
                <% @product.product_attachments.each do |attachment| %>
                    <div class="col-xs-6 col-md-4 form-group grayscale">
                        <img src="<%= attachment.attachment.small.url %>" class="upload-photo-image">
                        <input type="hidden" name="product_attachment[id][]" value="<%= attachment.id %>">
                        <button class="delete-photo-btn overlay-btn js-delete-photo-btn delete-attachment" data-toggle="tooltip" data-placement="top" title="Delete" data-photo-id="143275119">
                            <i class="fa fa-trash-o"></i>
                         </button>
                         <button class="cover-photo-btn cover-overlay-btn js-delete-photo-btn cover-attachment" data-toggle="tooltip" data-placement="top" title="Set as cover photo" data-photo-id="143275119">
                            <i class="fa fa-picture-o"></i>
                         </button>
                    </div>
                <% end %>
            <% end %>

            <div class="col-xs-6 col-md-4 form-group">
                <div class="thumbnail panel photo-item empty-photo-frame" name="empty-photo-frame">
                    <img src="<%= asset_url('add-image-placeholder.png') %>">
                </div>
            </div>

        </div>
        <hr>
        <div class="row">
            <div class="col-xs-12 next-bottom paddingzero">
                <div class="col-xs-6">
                    <% if @product.new_record? %>
                        <a href="#" class="btn-back">Back</a>
                    <% else %>
                        <a href="/products/<%= @product.id %>/edit_location" class="btn-back">Back</a>
                    <% end %>
                </div>
                <div class="col-xs-6">
                    <% if @product.new_record? %>
                        <a href="" class="btn btn-next pull-right">See Next</a>
                        <a href="/products/<%= @product.id %>/edit_price" class="btn btn-next pull-right">See Next</a>
                    <% else %>
                        <input type="hidden" name="step-param" value="photo">
                        <%= f.submit 'See Next', :class => 'btn btn-next pull-right photo-submit' %>
                    <% end %>
                </div>
            </div>
        </div>
    <% end %>
</section>

Answer 1

您可以查看product_attachment_params我认为此参数中没有product_id字段，因为我在表单中看不到product_id字段。 你也可以使用

@product.product_attachments.build(product_attachment_params)

Answer 2

在控制器中执行以下操作：

class ProductAttachmentsController < ApplicationController

def create
    product_id = session[:product_id]
    # Look for the product by product_id and create your attachment from there.
    @product_attachment = Product.find(product_id).build(product_attachment_params)

    respond_to do |format|
      if @product_attachment.save
        format.html { redirect_to @product_attachment, notice: 'Product attachment was successfully created.' }
        # format.json { render :show, status: :created, location: @product_attachment }
        format.json {render :json => @product_attachment}
      else
        format.html { render :new }
        format.json { render json: @product_attachment.errors, status: :unprocessable_entity }
      end
    end
  end

end