Direct Download Base

Download large reports (Excel/PDF/CSV) using less memory. The file is generated on disk and delivered through a download link.

Benefits

• Better for heavy reports (kardex, stock moves, valuations, etc.).
• Avoids huge base64 data in RAM (more stable / lower memory usage).
• Faster than saving into Binary fields or attachments just to download.

Note: Excel has a limit of 1,048,576 rows per sheet (Microsoft Excel limitation).

Standard Odoo vs this module

• Standard: usually uses Binary/base64 (more RAM) or ir.attachment.
• Here: the file is written to disk and downloaded via URL (no base64).
• “One-shot” download: the file is removed when the download starts.

How to use it (the most important part)

• 1) Add dependency: direct_download_base
• 2) Inherit the mixin: direct.download.mixin
• 3) Generate the XLSX writing to output.part_path
• 4) Return: return output.action()

Minimal example (XLSX):

# __manifest__.py (your module)
# "depends": ["direct_download_base", ...]

import xlsxwriter
from odoo import models, _

class MyWizard(models.TransientModel):
    _name = "my.wizard"
    _inherit = ["direct.download.mixin"]

    def action_export(self):
        self.ensure_one()

        output = self.dd_output_xlsx(_("Report") + ".xlsx")

        wb = xlsxwriter.Workbook(output.part_path, {
            "constant_memory": True,
            "default_date_format": "dd/mm/yyyy",
        })

        ws = wb.add_worksheet("Report")
        ws.write(0, 0, "Hello")

        wb.close()
        return output.action()
      

Permissions: Odoo must be able to write to data_dir. Temp files are stored in: data_dir/direct_download/<dbname>/

Tip: you don’t need output.seek(0) (that only applies to BytesIO/base64).