Quote PDFs in Django

Why quotes become PDFs

A quote is an offer with an expiry, and it gets forwarded to people who will never log into your product. It has to stand alone and it has to be fixed at the moment it was sent. That is the difference between a document and a view of a database, and it is why sales teams keep asking for this.

What a quote has to carry

Before any of the code below matters, the template has to produce a document that is actually a quote. These are the fields that make it one, and the ones a reader or an auditor will look for first.

• a quote reference, which the eventual order will cite
• the validity date, after which the pricing no longer stands
• each line with the price offered, which may not be list price
• any discount shown as a discount rather than folded into the unit price
• the terms attached to the offer: payment schedule, lead time, exclusions

Turning your the Django template language template into a document

You already have the markup. Render_to_string("invoices/detail.html", context) gives you it as a string, which is the only input the render needs. Django resolves {% static %} to a path relative to STATIC_URL, which means the stylesheet URL in your rendered HTML is only meaningful to a browser that already has a session on your host. A renderer fetching it from outside gets a 404 and produces an unstyled document. Inline the CSS into the string you send, or make STATIC_URL absolute for this one code path.

The Django implementation

httpx is the client most projects here already have. The render happens in a view that returns FileResponse, and you hand the bytes back as a FileResponse with an explicit content type.

# views.py
import httpx
from django.conf import settings
from django.http import FileResponse
from django.shortcuts import get_object_or_404
from django.template.loader import render_to_string

from .models import Quote


def quote_pdf(request, pk):
    quote = get_object_or_404(Quote, pk=pk)

    # A template that extends nothing. The on-screen template carries base.html,
    # the nav and the messages block, none of which belong in a quote.
    html = render_to_string("quotes/pdf.html", {"quote": quote})

    upstream = httpx.stream(
        "POST",
        "https://api.pdfpipe.xyz/v1/pdf",
        headers={"Authorization": f"Bearer {settings.PDFPIPE_KEY}"},
        json={"html": html, "options": {"format": "A4", "printBackground": True}},
        timeout=60.0,
    )

    response = upstream.__enter__()
    response.raise_for_status()

    return FileResponse(
        response.iter_bytes(),
        content_type="application/pdf",
        filename=f"quote-{quote.reference}.pdf",
    )

The CSS that makes a quote page correctly

The layout problem specific to this document is that optional line items and discount blocks make the length unpredictable, so the signature area must not orphan onto a page of its own. These rules handle it.

/* Backgrounds are dropped unless printBackground is set on the
   request, which is the usual reason a document renders in plain
   black and white when it looked right in the browser. */
@page {
  size: A4;
  margin: 18mm 16mm;
}

table { break-inside: avoid; }
h2    { break-after: avoid; }

What goes wrong in Django

The template that renders your on-screen view is almost always the wrong one to send. It carries the base layout, the nav, and the messages framework, all of which land in the PDF. Render a template that extends nothing, and keep it beside the view template so the two do not drift.

What people try first

Most Django projects reach for WeasyPrint or xhtml2pdf, both of which put layout in your Python process. WeasyPrint needs Cairo and Pango in the image; xhtml2pdf supports a subset of CSS that stopped growing years ago. That works until it is running on more than one machine, at which point the browser becomes the thing you operate rather than the thing you use.

Where the quote lives afterwards

Rendering is the short part. A quote is dead once it expires or converts, so retention is short and driven by the sales system rather than by law. What matters is that the version the customer received is the one you can produce later, because a disputed price is settled by the document that was sent.

Getting the document right

• Check the validity date, since a quote without one is an open-ended commitment.
• Generation is triggered by a salesperson sending it, so latency is felt directly by a person waiting, so size the timeout for that path rather than for a health check.
• These are produced one at a time by a person who is waiting, so latency is felt directly.
• Backgrounds are painted by default here, so a design that uses colour needs nothing set. Only an explicit print_background of false turns them off.

Frequently asked

Related

Other Django documents, and the same quote in other stacks.