Rails自定义路由form_for错误：param丢失或值为空

Question

我得到此错误：param is missing or the value is empty: character。我很困惑。在某处某处form_for必须存在问题，但我无法找到它。我正在更新Users控制器中的Character属性，但我认为这应该不重要？

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"} 

的意见/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。如果你看表​​格数据：

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

没有character参数。

正确的name属性会是这个样子：

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

当Rails的解析表单数据，将其转换成以下散列：

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

你并不需要指定名称手动：

<%= 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会给你正确的名称属性。你也不需要手动创建相关的记录 - 这是的accepts_nested_attributes_for整点：

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