Question

我们有一个应用程序必须使用在.net上运行的外部数据库进行身份验证。有一个单独的Rails应用程序，作为处理身份验证的gem安装。当有人进行身份验证时，他们的信息将存储在会话对象中。应用程序本身就是一种讨论论坛。

当我通过附件控制器创建附件时，所有属性都会正确保存到数据库中。但是，当我在讨论模型中使用nested_attributes_for执行此操作时，只会传递定义的paperclip属性。 created_by属性为null。否则，其他一切都是一样的。

为什么没有将此属性添加到数据库？

讨论模式：

class Discussion < ActiveRecord::Base
  belongs_to :creator, :class_name => "Person", :foreign_key => "created_by"
  belongs_to :updater, :class_name => "Person", :foreign_key => "updated_by"
  belongs_to :discussion_group
  belongs_to :discussion_category
  has_many :discussion_comments, dependent: :destroy
  has_many :discussion_attachments, dependent: :destroy
  accepts_nested_attributes_for :discussion_attachments, allow_destroy: true
  validates :discussion_group_id, on: :create, presence: :true
  validates :subject, :body, presence: :true
  validates :external_id, on: :create, uniqueness: :true
  before_create :add_external_id
  validates_associated :creator, :updater, :discussion_group,      :discussion_comments, :discussion_attachments
  scope :for_discussion_group_ids, ->(ids) {where('discussion_group_id IN (?)', ids)}
  scope :for_ext_id, ->(id) {where(external_id: id).first}

  ....

讨论附件模型：

ALLOWABLE_IMAGES = ["image/gif", "image/jpeg", "image/jpg", "image/png"]
ALLOWABLE_APPLICATIONS = ["application/vnd.oasis.opendocument.text",
"application/vnd.oasis.opendocument.spreadsheet",
"application/vnd.oasis.opendocument.presentation",
"application/vnd.ms-excel",
"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
"application/vnd.ms-powerpoint",
"application/vnd.openxmlformats-officedocument.presentationml.presentation",
"application/vnd.openxmlformats-officedocument.wordprocessingml.document",
"application/vnd.ms-word", "application/pdf", "text/plain"]

class DiscussionAttachment < ActiveRecord::Base
  belongs_to :discussion
  belongs_to :creator, :class_name => "Person", :foreign_key => "created_by"
  belongs_to :updater, :class_name => "Person", :foreign_key => "created_by"
  has_attached_file :document
  validates_attachment :document, :presence => true,
    :content_type => { :content_type => ALLOWABLE_APPLICATIONS + ALLOWABLE_IMAGES },
    :size => { :in => 0..5.megabytes }
end

讨论控制员：

class DiscussionsController < ApplicationController
  before_action :set_discussion, only: [:show, :destroy]
  before_action :authorized_for_discussion?, only: [:show]
  before_action :authorized_to_start_discussion?, only: [:new, :create]

...

  def new
    @discussion = Discussion.new
    @discussion_group = DiscussionGroup.find(params[:discussion_group_id])
    @categories = DiscussionCategory.show.collect{|category| [category.name, category.id]}
    3.times {@discussion.discussion_attachments.build(created_by: current_user.PersonID)}
  end

  def create
    @discussion = Discussion.new(discussion_params.merge!({discussion_group_id: params[:discussion_group_id]}))
    @discussion.created_by = current_user.PersonID

    respond_to do |format|
      if @discussion.save
        flash[:success] = 'Discussion created successfully.'
        format.html { redirect_to discussion_group_discussion_path(@discussion.discussion_group, @discussion), notice: 'Discussion was successfully created.' }
        format.json { render action: 'show', status: :created, location: @discussion }
        Notify.new_discussion_notification(@discussion).deliver
      else
        flash[:error] = 'Discussion not created.'
        @discussion_group = DiscussionGroup.find(params[:discussion_group_id])
        3.times {@discussion.discussion_attachments.build(created_by: current_user.PersonID)}
        format.html { render action: 'new' }
        format.json { render json: @discussion.errors, status: :unprocessable_entity }
      end
    end
  end

 ...

  private

  ...

    def set_discussion
      @discussion = Discussion.find(params[:id])
    end


    def discussion_params
      params.require(:discussion).permit(:discussion_group_id, :discussion_category_id, :subject, :body, :document, discussion_attachments_attributes: [:id, :document])
    end
end

讨论观点：

=render partial: 'shared/error_messages', locals: {object: @discussion}

%h1 Create Discussion
%h4 #{@discussion_group.name }

.form-box
  =form_for @discussion, url: discussion_group_discussions_path, html: {multipart: true}, method: :post do |f|
    =f.hidden_field :discussion_group_id, value: @discussion_group.id
    .row
      .col-md-8.form-group
        =f.label :subject
        %span.required *
        =f.text_field :subject, class: "form-control", placeholder: 'Enter a subject for your discussion'

      .col-md-4.form-group
        =f.label :discussion_category, 'Discussion Category'
        =f.select :discussion_category_id, DiscussionCategory.show.collect{|category| [category.name, category.id]}, {prompt: true}, {class: 'dropselection form-control'}


    .row
      .col-md-8.form-group
        =f.label :body, "Body"
        %span.required *
        =f.text_area :body, class: "form-control", rows: 10

      .col-md-4.form-group
        %label Upload Files
        = f.fields_for :discussion_attachments, :html => {class: "form-control"} do |builder|
          = builder.file_field :document
          %br

    .form-group.row
      .col-md-12
        =f.submit 'Create', class: "btn btn-default"
        = link_to 'Cancel', discussion_group_path(@discussion_group), class: 'btn btn-default'

    .row
      .col-md-12
        %small
          %span.required *
          Denotes required fields
%br

感谢您提供任何帮助。

Answer 1

如果有人遇到这样的问题。查看rails日志并找出params hash的样子。我遇到的问题是由于构建了多个附件字段，所以：discussion_attachments_attributes指向一个哈希，其键值是附件数组的索引。就我而言，有3个领域。

所以，我在讨论控制器中创建了一个私有方法：

def set_attachments_created_by
 attrs = params[:discussion][:discussion_attachments_attributes]
 attrs['0'][:created_by] = current_user.PersonID if attrs['0'].present?
 attrs['1'][:created_by] = current_user.PersonID if attrs['1'].present?
 attrs['2'][:created_by] = current_user.PersonID if attrs['2'].present?
end

然后在创建中，我在创建讨论之前调用该方法：

def create
  set_attachments_created_by if params[:discussion][:discussion_attachments_attributes].present?
  @discussion = Discussion.new(discussion_params)
  @discussion.created_by = current_user.PersonID
  ....

这可能是一种更优雅的方法，但它可以用于此目的，并允许nested_attribute传递给DiscussionAttachments模型。只需记住在强参数声明中添加：created_by。

通过Rails中的nested_attributes传递current_user ID

1 个答案: