在rails应用程序中从多个模型创建pdf文件

这里排序教程如何使用prawn pdf打印相关模型

例如我有父模型，它有很多汽车（相关模型）

class Parent < ActiveRecord::Base
  has_many :cars, dependent: :destroy
  accepts_nested_attributes_for :cars, allow_destroy: :true
end

在我的控制器中，我定义如下

class ParentsController < ApplicationController

  def show
      @parent = Parent.find(params[:id])

      respond_to do |format|
        format.html     
        format.pdf do
            # here you call prawn pdf class (see below)
            pdf = ParentPdf.new(@parent)
            send_data pdf.render, filename: 'family.pdf',
                                  type: 'application/pdf',
                                  disposition: 'inline'
          end
        end
      end
    end
  end
end

您可以按照 app/pdf/parent_pdf.rb 创建文件夹和文件，它继承自 Prawn::Document 类

class ParentPdf < Prawn::Document

  def initialize(parent)
    # init margin and size
    super(top_margin: 5, left_margin: 5, page_size: 'A4', page_layout: :landscape, print_scaling: :none)

    # pass argument to variable
    @parent = parent
    # here is you access related models like you access from your controller
    @cars = @parent.cars
    # you print the model
    print_header 
    # and print related model
    print_detail
  end 

  def print_header
    bounding_box([420, 510], width: 350, height: 90) do
      text "name: #{@parent.name}", size: 11
    end
  end

  def print_detail
    font 'Helvetica'
    font_size 9
    @cars.each do |car|
      text "car: #{car.name}", size: 11
    end
  end

end

最后是通过超链接打印pdf的命令

<%= link_to 'print pdf', parent_path(parent, format: "pdf"), :class => 'btn btn-sm btn-secondary' %>