# Rails 圖片（在地） > https://guides.rubyonrails.org/active_storage_overview.html ## 1.首先把Ｇemfile的 `gem "image_processing", ">= 1.2"` ## 這行註解取消掉。 終端機執行```rails active_storage:install ``` ## 2.在`config/environments/development.rb`加上 ```ruby # Store files locally. config.active_storage.service = :local ``` 如果要用s3 ```ruby # Store files on Amazon S3. config.active_storage.service = :amazon ``` 並且在`config/storage.yml`加上 ```ruby local: service: Disk root: <%= Rails.root.join("storage") %> test: service: Disk root: <%= Rails.root.join("tmp/storage") %> amazon: service: S3 access_key_id: "" secret_access_key: "" bucket: "" region: "" # e.g. 'us-east-1' ``` ## 3.has_one_attached 在想要加上圖片功能的model加上has_one_attached，這裡用User這個model，:avatar是符號，可以改成其他名字例如:image ```ruby class User < ApplicationRecord has_one_attached :avatar end ``` 如果沒有這個model也可以用終端機增加 ``` bin/rails generate model User avatar:attachment ``` 在你的form表單上用 ```ruby <%= form.file_field :avatar %> ``` 並且在controller上permit :avatar ```ruby class SignupController < ApplicationController def create user = User.create!(user_params) session[:user_id] = user.id redirect_to root_path end private def user_params params.require(:user).permit(:email_address, :password, :avatar) end end ``` 想要把圖片呈現在view上的話， ```ruby <%= image_tag user.avatar %> ``` ```ruby <%= image_tag user.avatar.variant(resize_to_limit: [100, 100]) if user.avatar.attached?%> ``` ``` if user.avatar.attached? ``` 判斷是否有圖片 ``` resize_to_limit ``` 用來限制其大小