在我的发票模型中,我使用state_machine宝石跟踪发票状态.当发票从“未结算”到“已结算”状态时,我想获取发票PDF的副本,并使用CarrierWave将其附加到发票模型.

我有三个部分分开工作：控制器创建一个PDF视图,模型跟踪状态,并在进行正确的转换时触发回调,并且CarrierWave设置正确.但是,我有一个时间让他们一起玩得很好.

如果我只想抓住发票的HTML版本,我可以从模型中调用render_to_string.但是render_to_string似乎在接收PDF二进制文件时窒息.如果我可以得到一个数据流,那么很容易将该数据写入临时文件并将其附加到上传者,但是我不知道如何获取数据流.

有什么想法吗？代码如下：

发票控制器

def show
  @invoice = @agg_class.find(params[:id])

  respond_to do |format|
    format.pdf do
      render_pdf
    end
    format.html # show.html.erb
    format.json { render json: @aggregation }
  end
end

…

def render_pdf(options = {})
  options[:pdf] = pdf_filename
  options[:layout] = 'pdf.html'
  options[:page_size] = 'Letter'
  options[:wkhtmltopdf] = '/usr/local/bin/wkhtmltopdf'
  options[:margin] = {
    :top      => '0.5in',:bottom   => '1in',:left     => '0in',:right    => '0in'
  }
  options[:footer] = {
    :html => {
      :template   => 'aggregations/footer.pdf.haml',:layout     => false,}
  }
  options[:header] = {
    :html => {
      :template   => 'aggregations/header.pdf.haml',}
  }
  render options
end

Invoice.rb

def create_pdf_copy

   # This does not work.    
   pdf_file = ApplicationController.new.render_to_string(
    :action => 'aggregations/show',:format => :pdf,:locals => { 
      :invoice => self
    }
  )

  # This part works fine if the above works.
  unless pdf_file.blank?
    self.uploads.clear
    self.uploads.create(:fileinfo => File.new(pdf_file),:job_id => self.job.id)
  end

end

UPDATE找到一个解决方案.

def create_pdf_copy

    wicked = WickedPdf.new

    # Make a PDF in memory
    pdf_file = wicked.pdf_from_string( 
        ActionController::Base.new().render_to_string(
            :template   => 'aggregations/show.pdf.haml',:layout     => 'layouts/pdf.html.haml',:locals     => { 
                :aggregation => self
            } 
        ),:pdf => "#{self.type}-#{self}",:layout => 'pdf.html',:page_size => 'Letter',:wkhtmltopdf => '/usr/local/bin/wkhtmltopdf',:margin => {
            :top      => '0.5in',:right    => '0in'
        },:footer => {
            :content => ActionController::Base.new().render_to_string({
                :template => 'aggregations/footer.pdf.haml',:layout => false
            })
        },:header => {
            :content => ActionController::Base.new().render_to_string({
                :template => 'aggregations/header.pdf.haml',:layout => false
            })
        }
    )

    # Write it to tempfile
    tempfile = Tempfile.new(['invoice','.pdf'],Rails.root.join('tmp'))
    tempfile.binmode
    tempfile.write pdf_file
    tempfile.close

    # Attach that tempfile to the invoice
    unless pdf_file.blank?
        self.uploads.clear
        self.uploads.create(:fileinfo => File.open(tempfile.path),:job_id => self.job.id)
        tempfile.unlink
    end

end