控制器中的 Rails 4 功能未运行

Question

我有一些我正在处理的 Rails 4 项目的代码。它使用 active_record (mysql2)，当我通过rails c（在生产或开发中）交互时，has_many :through 关系可以正常工作。当我尝试在表单中提交关系时（我使用的是 simple_form），我似乎无法保存它。

这是我目前的信息设置方式（仅显示 sn-ps，我无法真正显示整个源）：

型号：

has_many :categorizations
has_many :resource_categories, through: :categorizations

accepts_nested_attributes_for :resource_categories
accepts_nested_attributes_for :categorizations

表格：

= simple_form_for @resource do |f|
  = f.association :resource_categories

控制器：

# POST /resources
# POST /resources.json
def create
  @resource = Resource.new(resource_params)
  set_categories(@resource, params[:resource][:resource_category_ids])

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

# PATCH/PUT /resources/1
# PATCH/PUT /resources/1.json
def update
  respond_to do |format|
    if @resource.update(resource_params)
      set_categories(@resource, params[:resource][:resource_category_ids])
      format.html {
        redirect_to @resource, notice: 'Resource was successfully updated.'
      }
      format.json {
        head :no_content
      }
    else
      format.html {
        render action: 'edit'
      }
      format.json {
        render json: @resource.errors, status: :unprocessable_entity
      }
    end
  end
end

# Never trust parameters from the scary internet, only allow the white list
# through.
def resource_params
  params.require(:resource).permit(
    :title, :slug, :ancestry, :status, :author_id, :published, :parent_id,
    :resource_category_ids, :preview, :body
  )
end

def set_categories(resource, categories)

  # Clean out the existing categories (if there are any)
  unless resource.resource_categories.blank?
    resource.resource_categories.each do |category|
      resource.resource_categories.delete(category)
    end
  end

  unless categories.blank?
    categories.each do |category|
      unless category.blank?
        resource.resource_categories << ResourceCategory.find(category)
      end
    end
  end
end

当我使用rails c -e production（或简单的rails c）发出以下命令时，它可以工作（在本例中，我将所有类别分配给所有资源）：

Resource.all.each do |resource|
  ResourceCategory.all.each do |category|
    resource.resource_categories << category
  end
end

看来我的问题是控制器没有调用辅助函数

Answer 1

改用这个：

def create
  @resource = Resource.new(resource_params)    
  @resource.set_categories(params[:resource][:resource_category_ids])
  ..
end 

在Resource模型中移动方法：

def set_categories(categories)

  # Clean out the existing categories (if there are any)
  unless new_record?
    unless resource_categories.blank?
      resource_categories.each do |category|
        resource_categories.delete(category)
      end
    end
  end

  unless categories.blank?
    categories.each do |category|
      unless category.blank?
        resource_categories << ResourceCategory.find(category)
      end
    end
  end
end

@resource 是控制器的实例变量，您不需要将其传递给方法。直接对实例变量执行所有操作。

OP在保存记录时仍然有问题，在resource_params方法中将:resource_category_ids更改为:resource_category_ids => []：

def resource_params 
params.require(:resource).permit( 
:title, :slug, :ancestry, :status, :author_id, :published, :parent_id, 
 :preview, :body, :resource_category_ids => [] 
) 
end