Rails调用文章中通过shrine上传的图片

gem 'shrine'

rails generate shrine:install

Shrine.storages = {
  cache: Shrine::Storage::FileSystem.new('public', prefix: 'uploads/cache'),
  store: Shrine::Storage::FileSystem.new('public', prefix: 'uploads'),
}

rails generate shrine:processor ImageProcessor

class Article < ApplicationRecord
  include Shrine::Attachment.new(:image)
end

rails generate migration AddImageToArticles image:string

rails db:migrate

<%= form_with model: @article, local: true do |form| %>
  <%= form.label :image %>
  <%= form.file_field :image %>
  <%= form.submit %>
<% end %>

class ArticlesController < ApplicationController
  def create
    @article = Article.new(article_params)
    if @article.save
      redirect_to @article, notice: 'Article was successfully created.'
    else
      render :new
    end
  end

  private

  def article_params
    params.require(:article).permit(:title, :content, :image)
  end
end

<%= image_tag @article.image_url(:medium) %>

Shrine.plugin :derivatives
Shrine.plugin :derivation_endpoint

Shrine.derivatives[:medium] = ->(io, context) {
  io.download do |original|
    MiniMagick::Tool.new('convert').call(original.path, '-resize', '300>', original.path)
  end
}

gem 'mini_magick'

class Article < ApplicationRecord
  include Shrine::Attachment.new(:image, versions: { medium: Shrine::Derivative[:medium] })
end