debian-weasyprint/weasyprint/__init__.py

444 lines
18 KiB
Python

"""
WeasyPrint
==========
WeasyPrint converts web documents to PDF.
The public API is what is accessible from this "root" packages
without importing sub-modules.
:copyright: Copyright 2011-2019 Simon Sapin and contributors, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
import contextlib
import os
import sys
from pathlib import Path
import cssselect2
import html5lib
import tinycss2
if sys.version_info.major < 3:
raise RuntimeError(
'WeasyPrint does not support Python 2.x anymore. '
'Please use Python 3 or install an older version of WeasyPrint.')
if hasattr(sys, 'frozen'):
if hasattr(sys, '_MEIPASS'):
# Frozen with PyInstaller
# See https://github.com/Kozea/WeasyPrint/pull/540
ROOT = Path(sys._MEIPASS)
else:
# Frozen with something else (py2exe, etc.)
# See https://github.com/Kozea/WeasyPrint/pull/269
ROOT = os.path.dirname(sys.executable)
else:
ROOT = Path(os.path.dirname(__file__))
VERSION = __version__ = (ROOT / 'VERSION').read_text().strip()
# Used for 'User-Agent' in HTTP and 'Creator' in PDF
VERSION_STRING = 'WeasyPrint %s (http://weasyprint.org/)' % VERSION
__all__ = ['HTML', 'CSS', 'Attachment', 'Document', 'Page',
'default_url_fetcher', 'VERSION']
# Import after setting the version, as the version is used in other modules
from .urls import ( # noqa isort:skip
fetch, default_url_fetcher, path2url, ensure_url, url_is_absolute)
from .logger import LOGGER, PROGRESS_LOGGER # noqa isort:skip
# Some imports are at the end of the file (after the CSS class)
# to work around circular imports.
class HTML(object):
"""Represents an HTML document parsed by html5lib.
You can just create an instance with a positional argument:
``doc = HTML(something)``
The class will try to guess if the input is a filename, an absolute URL,
or a :term:`file object`.
Alternatively, use **one** named argument so that no guessing is involved:
:type filename: str or pathlib.Path
:param filename: A filename, relative to the current directory, or
absolute.
:type url: str
:param url: An absolute, fully qualified URL.
:type file_obj: :term:`file object`
:param file_obj: Any object with a ``read`` method.
:type string: str
:param string: A string of HTML source.
Specifying multiple inputs is an error:
``HTML(filename="foo.html", url="localhost://bar.html")``
will raise a :obj:`TypeError`.
You can also pass optional named arguments:
:type encoding: str
:param encoding: Force the source character encoding.
:type base_url: str
:param base_url: The base used to resolve relative URLs
(e.g. in ``<img src="../foo.png">``). If not provided, try to use
the input filename, URL, or ``name`` attribute of :term:`file objects
<file object>`.
:type url_fetcher: function
:param url_fetcher: A function or other callable
with the same signature as :func:`default_url_fetcher` called to
fetch external resources such as stylesheets and images.
(See :ref:`url-fetchers`.)
:type media_type: str
:param media_type: The media type to use for ``@media``.
Defaults to ``'print'``. **Note:** In some cases like
``HTML(string=foo)`` relative URLs will be invalid if ``base_url``
is not provided.
"""
def __init__(self, guess=None, filename=None, url=None, file_obj=None,
string=None, encoding=None, base_url=None,
url_fetcher=default_url_fetcher, media_type='print'):
PROGRESS_LOGGER.info(
'Step 1 - Fetching and parsing HTML - %s',
guess or filename or url or
getattr(file_obj, 'name', 'HTML string'))
result = _select_source(
guess, filename, url, file_obj, string, base_url, url_fetcher)
with result as (source_type, source, base_url, protocol_encoding):
if isinstance(source, str):
result = html5lib.parse(source, namespaceHTMLElements=False)
else:
result = html5lib.parse(
source, override_encoding=encoding,
transport_encoding=protocol_encoding,
namespaceHTMLElements=False)
assert result
self.base_url = find_base_url(result, base_url)
self.url_fetcher = url_fetcher
self.media_type = media_type
self.wrapper_element = cssselect2.ElementWrapper.from_html_root(
result, content_language=None)
self.etree_element = self.wrapper_element.etree_element
def _ua_stylesheets(self):
return [HTML5_UA_STYLESHEET]
def _ph_stylesheets(self):
return [HTML5_PH_STYLESHEET]
def _get_metadata(self):
return get_html_metadata(self.wrapper_element, self.base_url)
def render(self, stylesheets=None, enable_hinting=False,
presentational_hints=False, font_config=None):
"""Lay out and paginate the document, but do not (yet) export it
to PDF or PNG.
This returns a :class:`~document.Document` object which provides
access to individual pages and various meta-data.
See :meth:`write_pdf` to get a PDF directly.
.. versionadded:: 0.15
:type stylesheets: list
:param stylesheets:
An optional list of user stylesheets. List elements are
:class:`CSS` objects, filenames, URLs, or file
objects. (See :ref:`stylesheet-origins`.)
:type enable_hinting: bool
:param enable_hinting:
Whether text, borders and background should be *hinted* to fall
at device pixel boundaries. Should be enabled for pixel-based
output (like PNG) but not for vector-based output (like PDF).
:type presentational_hints: bool
:param presentational_hints: Whether HTML presentational hints are
followed.
:type font_config: :class:`~fonts.FontConfiguration`
:param font_config: A font configuration handling ``@font-face`` rules.
:returns: A :class:`~document.Document` object.
"""
return Document._render(
self, stylesheets, enable_hinting, presentational_hints,
font_config)
def write_pdf(self, target=None, stylesheets=None, zoom=1,
attachments=None, presentational_hints=False,
font_config=None):
"""Render the document to a PDF file.
This is a shortcut for calling :meth:`render`, then
:meth:`Document.write_pdf() <document.Document.write_pdf>`.
:type target: str, pathlib.Path or file object
:param target:
A filename where the PDF file is generated, a file object, or
:obj:`None`.
:type stylesheets: list
:param stylesheets:
An optional list of user stylesheets. The list's elements
are :class:`CSS` objects, filenames, URLs, or file-like
objects. (See :ref:`stylesheet-origins`.)
:type zoom: float
:param zoom:
The zoom factor in PDF units per CSS units. **Warning**:
All CSS units are affected, including physical units like
``cm`` and named sizes like ``A4``. For values other than
1, the physical CSS units will thus be "wrong".
:type attachments: list
:param attachments: A list of additional file attachments for the
generated PDF document or :obj:`None`. The list's elements are
:class:`Attachment` objects, filenames, URLs or file-like objects.
:type presentational_hints: bool
:param presentational_hints: Whether HTML presentational hints are
followed.
:type font_config: :class:`~fonts.FontConfiguration`
:param font_config: A font configuration handling ``@font-face`` rules.
:returns:
The PDF as :obj:`bytes` if ``target`` is not provided or
:obj:`None`, otherwise :obj:`None` (the PDF is written to
``target``).
"""
return self.render(
stylesheets, enable_hinting=False,
presentational_hints=presentational_hints,
font_config=font_config).write_pdf(
target, zoom, attachments)
def write_image_surface(self, stylesheets=None, resolution=96,
presentational_hints=False, font_config=None):
"""Render pages vertically on a cairo image surface.
.. versionadded:: 0.17
There is no decoration around pages other than those specified in CSS
with ``@page`` rules. The final image is as wide as the widest page.
Each page is below the previous one, centered horizontally.
This is a shortcut for calling :meth:`render`, then
:meth:`Document.write_image_surface()
<document.Document.write_image_surface>`.
:type stylesheets: list
:param stylesheets:
An optional list of user stylesheets. The list's elements
are :class:`CSS` objects, filenames, URLs, or file-like
objects. (See :ref:`stylesheet-origins`.)
:type resolution: float
:param resolution:
The output resolution in PNG pixels per CSS inch. At 96 dpi
(the default), PNG pixels match the CSS ``px`` unit.
:type presentational_hints: bool
:param presentational_hints: Whether HTML presentational hints are
followed.
:type font_config: :class:`~fonts.FontConfiguration`
:param font_config: A font configuration handling ``@font-face`` rules.
:returns: A cairo :class:`ImageSurface <cairocffi.ImageSurface>`.
"""
surface, _width, _height = (
self.render(stylesheets, enable_hinting=True,
presentational_hints=presentational_hints,
font_config=font_config)
.write_image_surface(resolution))
return surface
def write_png(self, target=None, stylesheets=None, resolution=96,
presentational_hints=False, font_config=None):
"""Paint the pages vertically to a single PNG image.
There is no decoration around pages other than those specified in CSS
with ``@page`` rules. The final image is as wide as the widest page.
Each page is below the previous one, centered horizontally.
This is a shortcut for calling :meth:`render`, then
:meth:`Document.write_png() <document.Document.write_png>`.
:type target: str, pathlib.Path or file object
:param target:
A filename where the PNG file is generated, a file object, or
:obj:`None`.
:type stylesheets: list
:param stylesheets:
An optional list of user stylesheets. The list's elements
are :class:`CSS` objects, filenames, URLs, or file-like
objects. (See :ref:`stylesheet-origins`.)
:type resolution: float
:param resolution:
The output resolution in PNG pixels per CSS inch. At 96 dpi
(the default), PNG pixels match the CSS ``px`` unit.
:type presentational_hints: bool
:param presentational_hints: Whether HTML presentational hints are
followed.
:type font_config: :class:`~fonts.FontConfiguration`
:param font_config: A font configuration handling ``@font-face`` rules.
:returns:
The image as :obj:`bytes` if ``target`` is not provided or
:obj:`None`, otherwise :obj:`None` (the image is written to
``target``.)
"""
png_bytes, _width, _height = (
self.render(stylesheets, enable_hinting=True,
presentational_hints=presentational_hints,
font_config=font_config)
.write_png(target, resolution))
return png_bytes
class CSS(object):
"""Represents a CSS stylesheet parsed by tinycss2.
An instance is created in the same way as :class:`HTML`, with the same
arguments.
An additional argument called ``font_config`` must be provided to handle
``@font-config`` rules. The same ``fonts.FontConfiguration`` object must be
used for different ``CSS`` objects applied to the same document.
``CSS`` objects have no public attributes or methods. They are only meant
to be used in the :meth:`~HTML.write_pdf`, :meth:`~HTML.write_png` and
:meth:`~HTML.render` methods of :class:`HTML` objects.
"""
def __init__(self, guess=None, filename=None, url=None, file_obj=None,
string=None, encoding=None, base_url=None,
url_fetcher=default_url_fetcher, _check_mime_type=False,
media_type='print', font_config=None, matcher=None,
page_rules=None):
PROGRESS_LOGGER.info(
'Step 2 - Fetching and parsing CSS - %s',
filename or url or getattr(file_obj, 'name', 'CSS string'))
result = _select_source(
guess, filename, url, file_obj, string,
base_url=base_url, url_fetcher=url_fetcher,
check_css_mime_type=_check_mime_type)
with result as (source_type, source, base_url, protocol_encoding):
if source_type == 'string' and not isinstance(source, bytes):
# unicode, no encoding
stylesheet = tinycss2.parse_stylesheet(source)
else:
if source_type == 'file_obj':
source = source.read()
stylesheet, encoding = tinycss2.parse_stylesheet_bytes(
source, environment_encoding=encoding,
protocol_encoding=protocol_encoding)
self.base_url = base_url
self.matcher = matcher or cssselect2.Matcher()
self.page_rules = [] if page_rules is None else page_rules
self.fonts = []
preprocess_stylesheet(
media_type, base_url, stylesheet, url_fetcher, self.matcher,
self.page_rules, self.fonts, font_config)
class Attachment(object):
"""Represents a file attachment for a PDF document.
.. versionadded:: 0.22
An instance is created in the same way as :class:`HTML`, except that the
HTML specific arguments (``encoding`` and ``media_type``) are not
supported. An optional description can be provided with the ``description``
argument.
:param description: A description of the attachment to be included in the
PDF document. May be :obj:`None`.
"""
def __init__(self, guess=None, filename=None, url=None, file_obj=None,
string=None, base_url=None, url_fetcher=default_url_fetcher,
description=None):
self.source = _select_source(
guess, filename, url, file_obj, string,
base_url=base_url, url_fetcher=url_fetcher)
self.description = description
@contextlib.contextmanager
def _select_source(guess=None, filename=None, url=None, file_obj=None,
string=None, base_url=None, url_fetcher=default_url_fetcher,
check_css_mime_type=False):
"""
Check that only one input is not None, and return it with the
normalized ``base_url``.
"""
if base_url is not None:
base_url = ensure_url(base_url)
selected_params = [
param for param in (guess, filename, url, file_obj, string) if
param is not None]
if len(selected_params) != 1:
raise TypeError('Expected exactly one source, got ' + (
', '.join(selected_params) or 'nothing'
))
elif guess is not None:
if hasattr(guess, 'read'):
type_ = 'file_obj'
elif isinstance(guess, Path):
type_ = 'filename'
elif url_is_absolute(guess):
type_ = 'url'
else:
type_ = 'filename'
result = _select_source(
base_url=base_url, url_fetcher=url_fetcher,
check_css_mime_type=check_css_mime_type,
**{type_: guess})
with result as result:
yield result
elif filename is not None:
if isinstance(filename, Path):
filename = str(filename)
if base_url is None:
base_url = path2url(filename)
with open(filename, 'rb') as file_obj:
yield 'file_obj', file_obj, base_url, None
elif url is not None:
with fetch(url_fetcher, url) as result:
if check_css_mime_type and result['mime_type'] != 'text/css':
LOGGER.error(
'Unsupported stylesheet type %s for %s',
result['mime_type'], result['redirected_url'])
yield 'string', '', base_url, None
else:
proto_encoding = result.get('encoding')
if base_url is None:
base_url = result.get('redirected_url', url)
if 'string' in result:
yield 'string', result['string'], base_url, proto_encoding
else:
yield (
'file_obj', result['file_obj'], base_url,
proto_encoding)
elif file_obj is not None:
if base_url is None:
# filesystem file-like objects have a 'name' attribute.
name = getattr(file_obj, 'name', None)
# Some streams have a .name like '<stdin>', not a filename.
if name and not name.startswith('<'):
base_url = ensure_url(name)
yield 'file_obj', file_obj, base_url, None
elif string is not None:
yield 'string', string, base_url, None
else:
sources = dict(locals())
sources_names = ', '.join(
name for name in ('guess', 'filename', 'url', 'file_obj', 'string')
if sources[name] is not None) or 'nothing'
raise TypeError('Expected exactly one source, got ' + sources_names)
# Work around circular imports.
from .css import preprocess_stylesheet # noqa isort:skip
from .html import ( # noqa isort:skip
HTML5_UA_STYLESHEET, HTML5_PH_STYLESHEET, find_base_url, get_html_metadata)
from .document import Document, Page # noqa isort:skip