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ruby-on-rails - ActiveStorage：NoMethodError（nil:NilClass 的未定义方法“[]”）

问题描述

过去 2 天我一直在调查这个问题，我正在运行 rails 5.3.2，我一直在尝试使用活动存储来上传已创建的用户的个人资料图片

我的模型如下所示：

MyModel < ApplicationRecord
  has_one_attached :avatar
  ...
end

我的控制器：

class MyModelsController < ApplicationController
  before_action :load_my_model, only: %i[edit show update]
  ...
  def update
    authorize @my_model

    @my_model.avatar.attach(params[:my_model][:avatar])

    respond_to do |format|
      if @my_model.update(model_params)
        format.html { redirect_to my_model_url(@my_model), notice: 'My model was successfully updated.' }
        format.json { render :show, status: :ok, location: @my_model }
      else
        format.html { render :edit }
        format.json { render json: @my_model.errors, status: :unprocessable_entity }
      end
    end
  end
  ...
  private

  def load_my_model
    @my_model = MyModel.find(params[:id])
  end
 end

每次在此行上都会引发错误：

 @my_model.avatar.attach(params[:my_model][:avatar])

错误： 

NoMethodError (undefined method `[]' for nil:NilClass):

(erb):19:in `<main>'
app/controllers/my_models_controller.rb:38:in `block in update'
app/controllers/my_models_controller.rb:37:in `update'

原始参数：

{
"utf8"=>"✓",
"authenticity_token"=>"*******REDACTED****", 
"my_model"=>
 {
  "name"=>"Bambam",
  "my_model_type"=>"",
  "country"=>"blue",
  "avatar"=>#<ActionDispatch::Http::UploadedFile:0x00007fdd275ce3e0 @tempfile=#<Tempfile:/var/folders/9p/llb8yydx59g535nqkbj0xv0w0000gp/T/RackMultipart20200201-7622-vp74wb.png>, @original_filename="undraw_instant_information_6755.png", @content_type="image/png", @headers="Content-Disposition: form-data; name=\"hair_stylist[avatar]\"; filename=\"undraw_instant_information_6755.png\"\r\nContent-Type: image/png\r\n">
 },
 "commit"=>"Update",
 "id"=>"2"
}

我试过：

我真的没有想法了，知道问题是什么吗？

标签： ruby-on-railsruby-on-rails-5rails-activestorage

解决方案

There is a issue related to rails credentials. if you just followed the active storage guide you might have configured a storage service provider at config/storage.yml. Regardless your using it as development storage service it will raise this exception when attaching files. For instance:

amazon:
  service: S3
    access_key_id: <%= Rails.application.credentials[Rails.env.to_sym][:aws][:access_key_id] %>
    secret_access_key: <%= Rails.application.credentials[Rails.env.to_sym][:aws][:secret_access_key] %>
    region: us-east-1
    bucket: ...

So make sure you have rails credentials set, or change it to your environment variables.

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