Question

我收到此错误：param is missing or the value is empty: character。我很困惑。 form_for必定存在问题，但我找不到它。我正在更新Character控制器中的Users属性，但这不应该重要吗？

参数：

{"utf8"=>"✓",
"_method"=>"patch",
"authenticity_token"=>"...",
"picturethings"=>{"picture"=>[#<ActionDispatch::Http::UploadedFile:0x000001100087f8 @tempfile=#<Tempfile:/var/folders/19/_vdcl1r913g6fzvk1l56x4km0000gn/T/RackMultipart20150524-4855-1eieu5j.jpeg>,
@original_filename="GOT1.jpeg",
@content_type="image/jpeg",
@headers="Content-Disposition: form-data; name=\"picturethings[picture][]\"; filename=\"GOT1.jpeg\"\r\nContent-Type: image/jpeg\r\n">]},
"commit"=>"Upload pictures",
"callsign"=>"bazzer"}

视图/用户/ edit.html.erb

<%= form_for @character, url: update_pictures_user_path do |f| %>
  <%= f.fields_for :picturethings, html: { multipart: true } do |p| %>
    <%= p.label :picture %>
    <%= p.file_field :picture, multiple: true, name: "picturethings[picture][]" %>
  <% end %>
  <%= f.submit "Upload pictures" %>
<% end %>

users_controller.rb

def edit
  @character = Character.find_by(callsign: params[:callsign])
  @user = @character.sociable
  @picturething = @character.picturethings.build
end

def update_pictures
  @character = Character.find_by(callsign: params[:callsign])
  if @character.update_attributes(update_pictures_user_params)
    flash[:success] = "Pictures updated"
    params[:picturethings]['picture'].each do |p|
      @picturething = @character.picturethings.create!(picture: p, character_id: @character.id)
    end
    render 'edit'
  else
    render 'edit'
  end
end

def update_pictures_user_params
  params.require(:character).permit(picturethings_attributes: [:picture])
end

character.rb

belongs_to :sociable, polymorphic: true
has_many :picturethings
accepts_nested_attributes_for :picturethings

user.rb

has_one  :character, as: :sociable, dependent: :destroy

的routes.rb

patch '/users/:callsign/update_pictures', to: 'users#update_pictures', as: :update_pictures_user

Answer 1

您的文件输入名称不正确。如果您查看表单数据：

form-data; name=\"picturethings[picture][]\"; filename=\"GOT1.jpeg\"\r\nContent-Type: image/jpeg\r\n"

没有character参数。

正确的名称属性如下所示：

character[picturethings_attributes][1][picture][]

当Rails分析表单数据时，它会将其转换为以下哈希：

character: {
  picturethings_attributes: {
    0 => {
      picture : [] # an array of files.
    }
  }
}

您无需手动指定名称：

<%= form_for @character, url: update_pictures_user_path do |f| %>
  <%= f.fields_for :picturethings, html: { multipart: true } do |p| %>
    <%= p.label :picture %>
    <%= p.file_field :picture, multiple: true %>
  <% end %>
  <%= f.submit "Upload pictures" %>
<% end %>

Rails会为您提供正确的名称属性。您也不需要手动创建相关记录 - 这是accepts_nested_attributes_for的全部内容：

def update_pictures
  @character = Character.find_by(callsign: params[:callsign])
  if @character.update_attributes(update_pictures_user_params)
    flash[:success] = "Pictures updated"
    render 'edit'
  else
    render 'edit'
  end
end

Rails自定义路由form_for错误：param丢失或值为空

1 个答案: