359 lines
12 KiB
Python
359 lines
12 KiB
Python
|
"""Specific handling for some HTML elements, especially replaced elements.
|
|||
|
|
|
|||
|
|
Replaced elements (eg. <img> elements) are rendered externally and behave as an
|
|||
|
|
atomic opaque box in CSS. In general, they may or may not have intrinsic
|
|||
|
|
dimensions. But the only replaced elements currently supported in WeasyPrint
|
|||
|
|
are images with intrinsic dimensions.
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
|
|||
|
|
try:
|
|||
|
|
# Available in Python 3.9+
|
|||
|
|
from importlib.resources import files
|
|||
|
|
except ImportError: # pragma: no cover
|
|||
|
|
# Deprecated in Python 3.11+
|
|||
|
|
from importlib.resources import read_text
|
|||
|
|
else:
|
|||
|
|
def read_text(package, resource):
|
|||
|
|
return (files(package) / resource).read_text('utf-8')
|
|||
|
|
|
|||
|
|
import re
|
|||
|
|
|
|||
|
|
from . import CSS, Attachment, css
|
|||
|
|
from .css import get_child_text
|
|||
|
|
from .css.counters import CounterStyle
|
|||
|
|
from .formatting_structure import boxes
|
|||
|
|
from .images import SVGImage
|
|||
|
|
from .logger import LOGGER
|
|||
|
|
from .urls import get_url_attribute
|
|||
|
|
|
|||
|
|
HTML5_UA_COUNTER_STYLE = CounterStyle()
|
|||
|
|
HTML5_UA = read_text(css, 'html5_ua.css')
|
|||
|
|
HTML5_UA_FORM = read_text(css, 'html5_ua_form.css')
|
|||
|
|
HTML5_PH = read_text(css, 'html5_ph.css')
|
|||
|
|
HTML5_UA_STYLESHEET = CSS(
|
|||
|
|
string=HTML5_UA, counter_style=HTML5_UA_COUNTER_STYLE)
|
|||
|
|
HTML5_UA_FORM_STYLESHEET = CSS(
|
|||
|
|
string=HTML5_UA_FORM, counter_style=HTML5_UA_COUNTER_STYLE)
|
|||
|
|
HTML5_PH_STYLESHEET = CSS(string=HTML5_PH)
|
|||
|
|
|
|||
|
|
# https://html.spec.whatwg.org/multipage/#space-character
|
|||
|
|
HTML_WHITESPACE = ' \t\n\f\r'
|
|||
|
|
HTML_SPACE_SEPARATED_TOKENS_RE = re.compile(f'[^{HTML_WHITESPACE}]+')
|
|||
|
|
|
|||
|
|
|
|||
|
|
def ascii_lower(string):
|
|||
|
|
r"""Transform (only) ASCII letters to lower case: A-Z is mapped to a-z.
|
|||
|
|
|
|||
|
|
This is used for `ASCII case-insensitive
|
|||
|
|
<https://whatwg.org/C#ascii-case-insensitive>`_ matching.
|
|||
|
|
|
|||
|
|
This is different from the :meth:`str.lower` method of Unicode strings
|
|||
|
|
which also affect non-ASCII characters,
|
|||
|
|
sometimes mapping them into the ASCII range:
|
|||
|
|
|
|||
|
|
>>> keyword = 'Bac\N{KELVIN SIGN}ground'
|
|||
|
|
>>> assert keyword.lower() == 'background'
|
|||
|
|
>>> assert ascii_lower(keyword) != keyword.lower()
|
|||
|
|
>>> assert ascii_lower(keyword) == 'bac\N{KELVIN SIGN}ground'
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
# This turns out to be faster than unicode.translate()
|
|||
|
|
return string.encode().lower().decode()
|
|||
|
|
|
|||
|
|
|
|||
|
|
def element_has_link_type(element, link_type):
|
|||
|
|
"""Return whether element has a ``rel`` attribute with given link type."""
|
|||
|
|
tokens = HTML_SPACE_SEPARATED_TOKENS_RE.findall(element.get('rel', ''))
|
|||
|
|
return any(ascii_lower(token) == link_type for token in tokens)
|
|||
|
|
|
|||
|
|
|
|||
|
|
# Maps HTML tag names to function taking an HTML element and returning a Box.
|
|||
|
|
HTML_HANDLERS = {}
|
|||
|
|
|
|||
|
|
|
|||
|
|
def handle_element(element, box, get_image_from_uri, base_url):
|
|||
|
|
"""Handle HTML elements that need special care.
|
|||
|
|
|
|||
|
|
:returns: a (possibly empty) list of boxes.
|
|||
|
|
"""
|
|||
|
|
if box.element_tag in HTML_HANDLERS:
|
|||
|
|
return HTML_HANDLERS[element.tag](
|
|||
|
|
element, box, get_image_from_uri, base_url)
|
|||
|
|
else:
|
|||
|
|
return [box]
|
|||
|
|
|
|||
|
|
|
|||
|
|
def handler(tag):
|
|||
|
|
"""Return a decorator registering a function handling ``tag`` elements."""
|
|||
|
|
def decorator(function):
|
|||
|
|
"""Decorator registering a function handling ``tag`` elements."""
|
|||
|
|
HTML_HANDLERS[tag] = function
|
|||
|
|
return function
|
|||
|
|
return decorator
|
|||
|
|
|
|||
|
|
|
|||
|
|
def make_replaced_box(element, box, image):
|
|||
|
|
"""Wrap an image in a replaced box.
|
|||
|
|
|
|||
|
|
That box is either block-level or inline-level, depending on what the
|
|||
|
|
element should be.
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
type_ = (
|
|||
|
|
boxes.BlockReplacedBox if 'block' in box.style['display']
|
|||
|
|
else boxes.InlineReplacedBox)
|
|||
|
|
new_box = type_(element.tag, box.style, element, image)
|
|||
|
|
# TODO: check other attributes that need to be copied
|
|||
|
|
# TODO: find another solution
|
|||
|
|
new_box.string_set = box.string_set
|
|||
|
|
new_box.bookmark_label = box.bookmark_label
|
|||
|
|
return new_box
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('img')
|
|||
|
|
def handle_img(element, box, get_image_from_uri, base_url):
|
|||
|
|
"""Handle ``<img>`` elements.
|
|||
|
|
|
|||
|
|
Return either an image or the alt-text.
|
|||
|
|
|
|||
|
|
See: https://www.w3.org/TR/html5/embedded-content-1.html#the-img-element
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
src = get_url_attribute(element, 'src', base_url)
|
|||
|
|
alt = element.get('alt')
|
|||
|
|
if src:
|
|||
|
|
image = get_image_from_uri(
|
|||
|
|
url=src, orientation=box.style['image_orientation'])
|
|||
|
|
if image is not None:
|
|||
|
|
return [make_replaced_box(element, box, image)]
|
|||
|
|
else:
|
|||
|
|
# Invalid image, use the alt-text.
|
|||
|
|
if alt:
|
|||
|
|
box.children = [boxes.TextBox.anonymous_from(box, alt)]
|
|||
|
|
return [box]
|
|||
|
|
elif alt == '':
|
|||
|
|
# The element represents nothing
|
|||
|
|
return []
|
|||
|
|
else:
|
|||
|
|
assert alt is None
|
|||
|
|
# TODO: find some indicator that an image is missing.
|
|||
|
|
# For now, just remove the image.
|
|||
|
|
return []
|
|||
|
|
else:
|
|||
|
|
if alt:
|
|||
|
|
box.children = [boxes.TextBox.anonymous_from(box, alt)]
|
|||
|
|
return [box]
|
|||
|
|
else:
|
|||
|
|
return []
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('embed')
|
|||
|
|
def handle_embed(element, box, get_image_from_uri, base_url):
|
|||
|
|
"""Handle ``<embed>`` elements, return either an image or nothing.
|
|||
|
|
|
|||
|
|
See: https://www.w3.org/TR/html5/embedded-content-0.html#the-embed-element
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
src = get_url_attribute(element, 'src', base_url)
|
|||
|
|
type_ = element.get('type', '').strip()
|
|||
|
|
if src:
|
|||
|
|
image = get_image_from_uri(
|
|||
|
|
url=src, forced_mime_type=type_,
|
|||
|
|
orientation=box.style['image_orientation'])
|
|||
|
|
if image is not None:
|
|||
|
|
return [make_replaced_box(element, box, image)]
|
|||
|
|
# No fallback.
|
|||
|
|
return []
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('object')
|
|||
|
|
def handle_object(element, box, get_image_from_uri, base_url):
|
|||
|
|
"""Handle ``<object>`` elements, return either an image or the fallback.
|
|||
|
|
|
|||
|
|
See: https://www.w3.org/TR/html5/embedded-content-0.html#the-object-element
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
data = get_url_attribute(element, 'data', base_url)
|
|||
|
|
type_ = element.get('type', '').strip()
|
|||
|
|
if data:
|
|||
|
|
image = get_image_from_uri(
|
|||
|
|
url=data, forced_mime_type=type_,
|
|||
|
|
orientation=box.style['image_orientation'])
|
|||
|
|
if image is not None:
|
|||
|
|
return [make_replaced_box(element, box, image)]
|
|||
|
|
# The element’s children are the fallback.
|
|||
|
|
return [box]
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('colgroup')
|
|||
|
|
def handle_colgroup(element, box, _get_image_from_uri, _base_url):
|
|||
|
|
"""Handle the ``span`` attribute."""
|
|||
|
|
if isinstance(box, boxes.TableColumnGroupBox):
|
|||
|
|
if not any(child.tag == 'col' for child in element):
|
|||
|
|
box.children = [
|
|||
|
|
boxes.TableColumnBox.anonymous_from(box, [])
|
|||
|
|
for _ in range(box.span)]
|
|||
|
|
return [box]
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('col')
|
|||
|
|
def handle_col(element, box, _get_image_from_uri, _base_url):
|
|||
|
|
"""Handle the ``span`` attribute."""
|
|||
|
|
if isinstance(box, boxes.TableColumnBox) and box.span > 1:
|
|||
|
|
# Generate multiple boxes
|
|||
|
|
# https://lists.w3.org/Archives/Public/www-style/2011Nov/0293.html
|
|||
|
|
return [box.copy() for _i in range(box.span)]
|
|||
|
|
return [box]
|
|||
|
|
|
|||
|
|
|
|||
|
|
@handler('{http://www.w3.org/2000/svg}svg')
|
|||
|
|
def handle_svg(element, box, get_image_from_uri, base_url):
|
|||
|
|
"""Handle ``<svg>`` elements.
|
|||
|
|
|
|||
|
|
Return either an image or the fallback content.
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
# TODO: handle href base for inline svg tags
|
|||
|
|
url_fetcher = get_image_from_uri.keywords['url_fetcher']
|
|||
|
|
context = get_image_from_uri.keywords['context']
|
|||
|
|
try:
|
|||
|
|
image = SVGImage(element, base_url, url_fetcher, context)
|
|||
|
|
except Exception as exception: # pragma: no cover
|
|||
|
|
LOGGER.error('Failed to load inline SVG: %s', exception)
|
|||
|
|
return []
|
|||
|
|
else:
|
|||
|
|
return [make_replaced_box(element, box, image)]
|
|||
|
|
|
|||
|
|
|
|||
|
|
def get_html_metadata(html):
|
|||
|
|
"""Get metadata dictionary out of HTML object.
|
|||
|
|
|
|||
|
|
Relevant specs:
|
|||
|
|
|
|||
|
|
https://www.whatwg.org/html#the-title-element
|
|||
|
|
https://www.whatwg.org/html#standard-metadata-names
|
|||
|
|
https://wiki.whatwg.org/wiki/MetaExtensions
|
|||
|
|
https://microformats.org/wiki/existing-rel-values#HTML5_link_type_extensions
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
title = None
|
|||
|
|
description = None
|
|||
|
|
generator = None
|
|||
|
|
keywords = []
|
|||
|
|
authors = []
|
|||
|
|
created = None
|
|||
|
|
modified = None
|
|||
|
|
attachments = []
|
|||
|
|
custom = {}
|
|||
|
|
lang = html.etree_element.attrib.get('lang', None)
|
|||
|
|
for element in html.wrapper_element.query_all('title', 'meta', 'link'):
|
|||
|
|
element = element.etree_element
|
|||
|
|
if element.tag == 'title' and title is None:
|
|||
|
|
title = get_child_text(element)
|
|||
|
|
elif element.tag == 'meta':
|
|||
|
|
name = ascii_lower(element.get('name', ''))
|
|||
|
|
content = element.get('content', '')
|
|||
|
|
if name == 'keywords':
|
|||
|
|
for keyword in map(strip_whitespace, content.split(',')):
|
|||
|
|
if keyword not in keywords:
|
|||
|
|
keywords.append(keyword)
|
|||
|
|
elif name == 'author':
|
|||
|
|
authors.append(content)
|
|||
|
|
elif name == 'description':
|
|||
|
|
if description is None:
|
|||
|
|
description = content
|
|||
|
|
elif name == 'generator':
|
|||
|
|
if generator is None:
|
|||
|
|
generator = content
|
|||
|
|
elif name == 'dcterms.created':
|
|||
|
|
if created is None:
|
|||
|
|
created = parse_w3c_date(name, content)
|
|||
|
|
elif name == 'dcterms.modified':
|
|||
|
|
if modified is None:
|
|||
|
|
modified = parse_w3c_date(name, content)
|
|||
|
|
elif name and name not in custom:
|
|||
|
|
custom[name] = content
|
|||
|
|
elif element.tag == 'link' and element_has_link_type(
|
|||
|
|
element, 'attachment'):
|
|||
|
|
url = get_url_attribute(element, 'href', html.base_url)
|
|||
|
|
attachment_title = element.get('title', None)
|
|||
|
|
if url is None:
|
|||
|
|
LOGGER.error('Missing href in <link rel="attachment">')
|
|||
|
|
else:
|
|||
|
|
attachment = Attachment(
|
|||
|
|
url=url, description=attachment_title,
|
|||
|
|
url_fetcher=html.url_fetcher)
|
|||
|
|
attachments.append(attachment)
|
|||
|
|
return {
|
|||
|
|
'title': title,
|
|||
|
|
'description': description,
|
|||
|
|
'generator': generator,
|
|||
|
|
'keywords': keywords,
|
|||
|
|
'authors': authors,
|
|||
|
|
'created': created,
|
|||
|
|
'modified': modified,
|
|||
|
|
'attachments': attachments,
|
|||
|
|
'lang': lang,
|
|||
|
|
'custom': custom,
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
|
|||
|
|
def strip_whitespace(string):
|
|||
|
|
"""Use the HTML definition of "space character",
|
|||
|
|
not all Unicode Whitespace.
|
|||
|
|
|
|||
|
|
https://www.whatwg.org/html#strip-leading-and-trailing-whitespace
|
|||
|
|
https://www.whatwg.org/html#space-character
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
return string.strip(HTML_WHITESPACE)
|
|||
|
|
|
|||
|
|
|
|||
|
|
# YYYY (eg 1997)
|
|||
|
|
# YYYY-MM (eg 1997-07)
|
|||
|
|
# YYYY-MM-DD (eg 1997-07-16)
|
|||
|
|
# YYYY-MM-DDThh:mmTZD (eg 1997-07-16T19:20+01:00)
|
|||
|
|
# YYYY-MM-DDThh:mm:ssTZD (eg 1997-07-16T19:20:30+01:00)
|
|||
|
|
# YYYY-MM-DDThh:mm:ss.sTZD (eg 1997-07-16T19:20:30.45+01:00)
|
|||
|
|
|
|||
|
|
W3C_DATE_RE = re.compile('''
|
|||
|
|
^
|
|||
|
|
[ \t\n\f\r]*
|
|||
|
|
(?P<year>\\d\\d\\d\\d)
|
|||
|
|
(?:
|
|||
|
|
-(?P<month>0\\d|1[012])
|
|||
|
|
(?:
|
|||
|
|
-(?P<day>[012]\\d|3[01])
|
|||
|
|
(?:
|
|||
|
|
T(?P<hour>[01]\\d|2[0-3])
|
|||
|
|
:(?P<minute>[0-5]\\d)
|
|||
|
|
(?:
|
|||
|
|
:(?P<second>[0-5]\\d)
|
|||
|
|
(?:\\.\\d+)? # Second fraction, ignored
|
|||
|
|
)?
|
|||
|
|
(?:
|
|||
|
|
Z | # UTC
|
|||
|
|
(?P<tz_hour>[+-](?:[01]\\d|2[0-3]))
|
|||
|
|
:(?P<tz_minute>[0-5]\\d)
|
|||
|
|
)
|
|||
|
|
)?
|
|||
|
|
)?
|
|||
|
|
)?
|
|||
|
|
[ \t\n\f\r]*
|
|||
|
|
$
|
|||
|
|
''', re.VERBOSE)
|
|||
|
|
|
|||
|
|
|
|||
|
|
def parse_w3c_date(meta_name, string):
|
|||
|
|
"""Parse datetimes as defined by the W3C.
|
|||
|
|
|
|||
|
|
See https://www.w3.org/TR/NOTE-datetime
|
|||
|
|
|
|||
|
|
"""
|
|||
|
|
if W3C_DATE_RE.match(string):
|
|||
|
|
return string
|
|||
|
|
else:
|
|||
|
|
LOGGER.warning(
|
|||
|
|
'Invalid date in <meta name="%s"> %r', meta_name, string)
|