pdf.py

# Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
# License: MIT. See LICENSE
import contextlib
import io
import os
import re
import subprocess

import pdfkit
from bs4 import BeautifulSoup
from packaging.version import Version
from pypdf import PdfReader, PdfWriter

import frappe
from frappe import _
from frappe.utils import scrub_urls
from frappe.utils.jinja_globals import bundled_asset, is_rtl

PDF_CONTENT_ERRORS = [
	"ContentNotFoundError",
	"ContentOperationNotPermittedError",
	"UnknownContentError",
	"RemoteHostClosedError",
]


def pdf_header_html(soup, head, content, styles, html_id, css):
	return frappe.render_template(
		"templates/print_formats/pdf_header_footer.html",
		{
			"head": head,
			"content": content,
			"styles": styles,
			"html_id": html_id,
			"css": css,
			"lang": frappe.local.lang,
			"layout_direction": "rtl" if is_rtl() else "ltr",
		},
	)


def pdf_body_html(template, args, **kwargs):
	try:
		return template.render(args, filters={"len": len})
	except Exception as e:
		# Guess line number ?
		frappe.throw(
			_("Error in print format on line {0}: {1}").format(
				_guess_template_error_line_number(template), e
			),
			exc=frappe.PrintFormatError,
			title=_("Print Format Error"),
		)


def _guess_template_error_line_number(template) -> int | None:
	"""Guess line on which exception occurred from current traceback."""
	with contextlib.suppress(Exception):
		import sys
		import traceback

		_, _, tb = sys.exc_info()

		for frame in reversed(traceback.extract_tb(tb)):
			if template.filename in frame.filename:
				return frame.lineno


def pdf_footer_html(soup, head, content, styles, html_id, css):
	return pdf_header_html(soup=soup, head=head, content=content, styles=styles, html_id=html_id, css=css)


def get_pdf(html, options=None, output: PdfWriter | None = None):
	html = scrub_urls(html)
	html, options = prepare_options(html, options)

	options.update({"disable-javascript": "", "disable-local-file-access": ""})

	filedata = ""
	if Version(get_wkhtmltopdf_version()) > Version("0.12.3"):
		options.update({"disable-smart-shrinking": ""})

	try:
		# Set filename property to false, so no file is actually created
		filedata = pdfkit.from_string(html, options=options or {}, verbose=True)

		# create in-memory binary streams from filedata and create a PdfReader object
		reader = PdfReader(io.BytesIO(filedata))
	except OSError as e:
		if any([error in str(e) for error in PDF_CONTENT_ERRORS]):
			if not filedata:
				print(html, options)
				frappe.throw(_("PDF generation failed because of broken image links"))

			# allow pdfs with missing images if file got created
			if output:
				output.append_pages_from_reader(reader)
		else:
			raise
	finally:
		cleanup(options)

	if "password" in options:
		password = options["password"]

	if output:
		output.append_pages_from_reader(reader)
		return output

	writer = PdfWriter()
	writer.append_pages_from_reader(reader)

	if "password" in options:
		writer.encrypt(password)

	filedata = get_file_data_from_writer(writer)

	return filedata


def get_file_data_from_writer(writer_obj):
	# https://docs.python.org/3/library/io.html
	stream = io.BytesIO()
	writer_obj.write(stream)

	# Change the stream position to start of the stream
	stream.seek(0)

	# Read up to size bytes from the object and return them
	return stream.read()


def prepare_options(html, options):
	if not options:
		options = {}

	options.update(
		{
			"print-media-type": None,
			"background": None,
			"images": None,
			"quiet": None,
			# 'no-outline': None,
			"encoding": "UTF-8",
			# 'load-error-handling': 'ignore'
		}
	)

	if not options.get("margin-right"):
		options["margin-right"] = "15mm"

	if not options.get("margin-left"):
		options["margin-left"] = "15mm"

	html, html_options = read_options_from_html(html)
	options.update(html_options or {})

	# cookies
	options.update(get_cookie_options())

	# page size
	pdf_page_size = (
		options.get("page-size") or frappe.db.get_single_value("Print Settings", "pdf_page_size") or "A4"
	)

	if pdf_page_size == "Custom":
		options["page-height"] = options.get("page-height") or frappe.db.get_single_value(
			"Print Settings", "pdf_page_height"
		)
		options["page-width"] = options.get("page-width") or frappe.db.get_single_value(
			"Print Settings", "pdf_page_width"
		)
	else:
		options["page-size"] = pdf_page_size

	return html, options


def get_cookie_options():
	options = {}
	if frappe.session and frappe.session.sid and hasattr(frappe.local, "request"):
		# Use wkhtmltopdf's cookie-jar feature to set cookies and restrict them to host domain
		cookiejar = f"/tmp/{frappe.generate_hash()}.jar"

		# Remove port from request.host
		# https://werkzeug.palletsprojects.com/en/0.16.x/wrappers/#werkzeug.wrappers.BaseRequest.host
		domain = frappe.utils.get_host_name().split(":", 1)[0]
		with open(cookiejar, "w") as f:
			f.write(f"sid={frappe.session.sid}; Domain={domain};\n")

		options["cookie-jar"] = cookiejar

	return options


def read_options_from_html(html):
	options = {}
	soup = BeautifulSoup(html, "html5lib")

	options.update(prepare_header_footer(soup))

	toggle_visible_pdf(soup)

	# use regex instead of soup-parser
	for attr in (
		"margin-top",
		"margin-bottom",
		"margin-left",
		"margin-right",
		"page-size",
		"header-spacing",
		"orientation",
		"page-width",
		"page-height",
	):
		try:
			pattern = re.compile(r"(\.print-format)([\S|\s][^}]*?)(" + str(attr) + r":)(.+)(mm;)")
			match = pattern.findall(html)
			if match:
				options[attr] = str(match[-1][3]).strip()
		except Exception:
			pass

	return str(soup), options


def prepare_header_footer(soup: BeautifulSoup):
	options = {}

	head = soup.find("head").contents
	styles = soup.find_all("style")

	print_css = bundled_asset("print.bundle.css").lstrip("/")
	css = frappe.read_file(os.path.join(frappe.local.sites_path, print_css))

	# extract header and footer
	for html_id in ("header-html", "footer-html"):
		if content := soup.find(id=html_id):
			content = content.extract()
			# `header/footer-html` are extracted, rendered as html
			# and passed in wkhtmltopdf options (as '--header/footer-html')
			# Remove instances of them from main content for render_template
			for tag in soup.find_all(id=html_id):
				tag.extract()

			toggle_visible_pdf(content)
			id_map = {"header-html": "pdf_header_html", "footer-html": "pdf_footer_html"}
			hook_func = frappe.get_hooks(id_map.get(html_id))
			html = frappe.get_attr(hook_func[-1])(
				soup=soup,
				head=head,
				content=content,
				styles=styles,
				html_id=html_id,
				css=css,
			)

			# create temp file
			fname = os.path.join("/tmp", f"frappe-pdf-{frappe.generate_hash()}.html")
			with open(fname, "wb") as f:
				f.write(html.encode("utf-8"))

			# {"header-html": "/tmp/frappe-pdf-random.html"}
			options[html_id] = fname
		else:
			if html_id == "header-html":
				options["margin-top"] = "15mm"
			elif html_id == "footer-html":
				options["margin-bottom"] = "15mm"

	return options


def cleanup(options):
	for key in ("header-html", "footer-html", "cookie-jar"):
		if options.get(key) and os.path.exists(options[key]):
			os.remove(options[key])


def toggle_visible_pdf(soup):
	for tag in soup.find_all(attrs={"class": "visible-pdf"}):
		# remove visible-pdf class to unhide
		tag.attrs["class"].remove("visible-pdf")

	for tag in soup.find_all(attrs={"class": "hidden-pdf"}):
		# remove tag from html
		tag.extract()


def get_wkhtmltopdf_version():
	wkhtmltopdf_version = frappe.cache.hget("wkhtmltopdf_version", None)

	if not wkhtmltopdf_version:
		try:
			res = subprocess.check_output(["wkhtmltopdf", "--version"])
			wkhtmltopdf_version = res.decode("utf-8").split(" ")[1]
			frappe.cache.hset("wkhtmltopdf_version", None, wkhtmltopdf_version)
		except Exception:
			pass

	return wkhtmltopdf_version or "0"