Rails：使用回形針上傳音頻文件返回NoMethodError

Question

我正在嘗試使用rails（5.1.4）構建一個簡單的音樂上傳/流式web應用程序。我已經安裝了回形針寶石，添加回形針遷移到我的曲目模型與 - $ rails g paperclip track audio，其中t.attachment :audio添加到我的軌道表，然後運行所有必要的分貝：遷移。然後我驗證:audio所以我track.rb模型現在看起來是這樣的：

class Track < ApplicationRecord 
    belongs_to :user 
    belongs_to :genre 

    has_attached_file :audio 
    validates :audio, presence: true 
    validates_attachment_content_type :audio, :content_type => [ 
    'audio/mpeg', 'audio/mp3' ] 
end 

然後在創建新的軌道，我添加的是，file_field標籤我_form.html.erb文件，所以現在看起來像這樣：

<%= simple_form_for @track do |f| %> 

<%= f.input :title, label: "Track Name:" %> 
<%= f.input :price %> 
<%= f.file_field :audio %> 
<%= select_tag(:genre_id, options_for_select(@genres), :prompt => "Select a Genre", class: "genre_select") %> 
<%= f.input :description %> 
<%= f.button :submit %> 
<% end %> 

曲目/新仍然正確呈現表單視圖，並讓我輸入的數據字段，但是，當我點擊「創建軌道」我得到一個錯誤NoMethod看起來像這樣：

這似乎與相關的流派不同意（我以前添加到軌道模型的另一個遷移）

對不起，這個瘋狂囉嗦的問題，林很新的軌道，所以我不能更好地解釋它..任何幫助將大規模讚賞。

還..這裏是我的軌道控制器看起來像以供參考：

class TracksController < ApplicationController 
    before_action :find_track, only: [:show, :edit, :update, :destroy] 

    def index 
    if params[:genre].blank? 
     @tracks = Track.all.order("created_at DESC") 
    else 
     @genre_id = Genre.find_by(name: params[:genre]).id 
     @tracks = Track.where(:genre_id => @genre_id).order("created_at DESC") 
    end 
    end 

    def new 
    #associates the new path to current user 
    @track = current_user.tracks.build 

    #gets all existing genres from table with all existing params, similar to a loop thru 
    @genres = Genre.all.map{ |g| [g.name, g.id]} 
    end 

    def show 
    # first finds track by id (code is in private find_track method) 
    end 

    def create 
    #initialises the create for the current user 
    @track = current_user.tracks.build(track_params) 

    # associates and passes in the selected genre param (id) into tracks table 
    @track.genre_id = params[:genre_id] 

    if @track.save 
     redirect_to root_path 
    else 
     render 'new' 
    end 

    end # --- end CREATE 

    def edit 
    #gets all existing genres from table with all existing params, similar to a loop thru 
    @genres = Genre.all.map{ |g| [g.name, g.id]} 
    end 

    def update 
    if @track.update(track_params) 
     redirect_to track_path(@track) 
    else 
     render 'edit' 
    end 
    end 

    def destroy 
    @track.destroy 
    redirect_to root_path 
    end 

private 

    def track_params 
    params.require(:track).permit(:title, :description, :artist, :genre_id, :price, :audio) 
    end 

    def find_track 
    @track = Track.find(params[:id]) 
    end 

end 

軌複製c Genre.all

2.4.0 :002 > Genre.all 
    Genre Load (1.3ms) SELECT "genres".* FROM "genres" LIMIT ? [["LIMIT", 11]] 
=> #<ActiveRecord::Relation [#<Genre id: 1, name: "Acoustic", created_at: "2017-09-11 12:53:37", updated_at: "2017-09-11 12:53:37">, #<Genre id: 2, name: "Electronic", created_at: "2017-09-11 12:54:02", updated_at: "2017-09-11 12:54:02">, #<Genre id: 3, name: "Rock", created_at: "2017-09-11 12:54:07", updated_at: "2017-09-11 12:54:07">, #<Genre id: 4, name: "Reggae", created_at: "2017-09-11 12:54:13", updated_at: "2017-09-11 12:54:13">, #<Genre id: 5, name: "Classical", created_at: "2017-09-11 12:54:19", updated_at: "2017-09-11 12:54:19">, #<Genre id: 6, name: "Piano", created_at: "2017-09-11 12:54:26", updated_at: "2017-09-11 12:54:26">, #<Genre id: 7, name: "Pop", created_at: "2017-09-11 12:54:29", updated_at: "2017-09-11 12:54:29">, #<Genre id: 8, name: "Theme", created_at: "2017-09-11 12:54:32", updated_at: "2017-09-11 12:54:32">, #<Genre id: 9, name: "Animation", created_at: "2017-09-11 12:54:36", updated_at: "2017-09-11 12:54:36">, #<Genre id: 10, name: "Country", created_at: "2017-09-11 12:54:55", updated_at: "2017-09-11 12:54:55">, ...]> 
2.4.0 :003 > 

Answer 1

我想你應該嘗試渲染你的部分像軌道/ new.html.erb：

<%= render 'tracks/form.html.erb', genres: @genres, track: @track %> 

並更新部分這樣的：

<%= simple_form_for track do |f| %> 
    <%= f.input :title, label: "Track Name:" %> 
    <%= f.input :price %> 
    <%= f.file_field :audio %> 
    <%= select_tag(:genre_id, options_for_select(genres), :prompt => "Select a Genre", class: "genre_select") %> 
    <%= f.input :description %> 
    <%= f.button :submit %> 
<% end %> 

好運。