railsAPI接收Base64文件

             tmp_dir = "tmp/pdf/"
              FileUtils.mkdir(tmp_dir) unless File.exists?(tmp_dir)
              pdf_tmp_path = "#{tmp_dir}#{file_name}.pdf"
              File.open(pdf_tmp_path, 'wb') { |f| f.write(Base64.decode64(pdf_base64_code)) }
              attachment = Attachment.new(attachment_entity_type: finance_bill.class.name, attachment_entity_id: finance_bill.id)
              File.open(pdf_tmp_path) do |f|
                attachment.path = f
              end
              attachment.save

# 导出txt价格
  def pubchem_txt
    head = %w{smiles PUBCHEM_EXT_DATASOURCE_REGID  PUBCHEM_SUBSTANCE_SYNONYM  PUBCHEM_EXT_SUBSTANCE_URL  PUBCHEM_EXT_DATASOURCE_URL PUBCHEM_GENERIC _REGISTRY_NAME}
    local_file_d = File.join("") 

    local_file_d << head.join("\t") + "\n" 

    chemical_ids = StockChemicalPriceRecord.select(:chemical_id).joins("left join ban_chemicals b on b.chemical_id = stock_chemical_price_records.chemical_id ").where('b.id is null ').group(:chemical_id)
    chemicals = Chemical.where(id:chemical_ids)
    chemicals.each do |chemical|
      data_list = ["#{chemical.smiles}","#{chemical.catalog_no}","#{chemical.name}","http://www.ichemical.com/products/#{chemical.cas}.html","http://www.ichemical.com","#{chemical.cas}"]
      local_file_d << data_list.join("\t") + "\n"
    end

    send_data(
        local_file_d,
        filename: "pubchem Package Info-#{rand(99999)}.txt",
        type: "application/txt",
        disposition: "attachment"
    )
  end