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307 lines
12 KiB
Python
307 lines
12 KiB
Python
# coding: utf8
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"""
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WeasyPrint
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==========
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WeasyPrint converts web documents to PDF.
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The public API is what is accessible from this "root" packages
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without importing sub-modules.
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:copyright: Copyright 2011-2012 Simon Sapin and contributors, see AUTHORS.
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:license: BSD, see LICENSE for details.
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"""
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from __future__ import division, unicode_literals
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VERSION = '0.17.1'
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__version__ = VERSION
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# Used for 'User-Agent' in HTTP and 'Creator' in PDF
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VERSION_STRING = 'WeasyPrint %s (http://weasyprint.org/)' % VERSION
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__all__ = ['HTML', 'CSS', 'Document', 'Page', 'default_url_fetcher',
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'VERSION']
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import lxml.etree
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from .urls import (default_url_fetcher, wrap_url_fetcher,
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path2url, ensure_url, url_is_absolute)
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from .logger import LOGGER
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# Some import are at the end of the file (after the CSS class) is defined
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# to work around circular imports.
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class HTML(object):
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"""Represents an HTML document parsed by `lxml <http://lxml.de/>`_.
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You can just create an instance with a positional argument:
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``doc = HTML(something)``
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The class will try to guess if the input is a filename, an absolute URL,
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or a file-like object.
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Alternatively, use **one** named argument so that no guessing is involved:
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:param filename: A filename, relative to the current directory or absolute.
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:param url: An absolute, fully qualified URL.
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:param file_obj: a file-like: any object with a :meth:`~file.read` method.
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:param string: a string of HTML source. (This argument must be named.)
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:param tree: a parsed lxml tree. (This argument must be named.)
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Specifying multiple inputs is an error: ``HTML(filename=foo, url=bar)``
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will raise.
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You can also pass optional named arguments:
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:param encoding: Force the source character encoding.
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:param base_url: The base used to resolve relative URLs
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(eg. in ``<img src="../foo.png">``). If not provided, try to use
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the input filename, URL, or ``name`` attribute of file-like objects.
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:param url_fetcher: a function or other callable
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with the same signature as :func:`default_url_fetcher` called to
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fetch external resources such as stylesheets and images.
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(See :ref:`url-fetchers`.)
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:param media_type: The media type to use for ``@media``.
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Defaults to ``'print'``. **Note:** In some cases like
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``HTML(string=foo)`` relative URLs will be invalid if ``base_url``
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is not provided.
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"""
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def __init__(self, guess=None, filename=None, url=None, file_obj=None,
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string=None, tree=None, encoding=None, base_url=None,
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url_fetcher=default_url_fetcher, media_type='print'):
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url_fetcher = wrap_url_fetcher(url_fetcher)
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source_type, source, base_url, protocol_encoding = _select_source(
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guess, filename, url, file_obj, string, tree, base_url,
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url_fetcher)
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if source_type == 'tree':
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result = source
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else:
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if source_type == 'string':
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parse = lxml.etree.fromstring
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else:
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parse = lxml.etree.parse
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if not encoding:
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encoding = protocol_encoding
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parser = lxml.etree.HTMLParser(encoding=encoding)
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result = parse(source, parser=parser)
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if result is None:
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raise ValueError('Error while parsing HTML')
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base_url = find_base_url(result, base_url)
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if hasattr(result, 'getroot'):
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result.docinfo.URL = base_url
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result = result.getroot()
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else:
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result.getroottree().docinfo.URL = base_url
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self.root_element = result
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self.base_url = base_url
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self.url_fetcher = url_fetcher
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self.media_type = media_type
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def _ua_stylesheets(self):
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return [HTML5_UA_STYLESHEET]
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def render(self, stylesheets=None, enable_hinting=False):
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"""Lay out and paginate the document, but do not (yet) export it
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to PDF or another format.
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This returns a :class:`~document.Document` object which provides
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access to individual pages and various meta-data.
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See :meth:`write_pdf` to get a PDF directly.
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.. versionadded:: 0.15
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:param stylesheets:
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An optional list of user stylesheets. (See
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:ref:`stylesheet-origins`\.) List elements are :class:`CSS`
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objects, filenames, URLs, or file-like objects.
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:type enable_hinting: bool
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:param enable_hinting:
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Whether text, borders and background should be *hinted* to fall
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at device pixel boundaries. Should be enabled for pixel-based
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output (like PNG) but not vector based output (like PDF).
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:returns: A :class:`~document.Document` object.
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"""
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return Document._render(self, stylesheets, enable_hinting)
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def write_pdf(self, target=None, stylesheets=None, zoom=1):
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"""Render the document to a PDF file.
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This is a shortcut for calling :meth:`render`, then
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:meth:`Document.write_pdf() <document.Document.write_pdf>`.
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:param target:
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A filename, file-like object, or :obj:`None`.
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:param stylesheets:
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An optional list of user stylesheets. (See
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:ref:`stylesheet-origins`\.) The list’s elements are
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:class:`CSS` objects, filenames, URLs, or file-like objects.
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:type zoom: float
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:param zoom:
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The zoom factor in PDF units per CSS units.
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**Warning**: All CSS units (even physical, like ``cm``)
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are affected.
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For values other than 1, physical CSS units will thus be “wrong”.
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Page size declarations are affected too, even with keyword values
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like ``@page { size: A3 landscape; }``
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:returns:
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The PDF as byte string if :obj:`target` is not provided or
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:obj:`None`, otherwise :obj:`None` (the PDF is written to
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:obj:`target`.)
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"""
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return self.render(stylesheets).write_pdf(target, zoom)
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def write_image_surface(self, stylesheets=None, resolution=96):
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surface, _width, _height = (
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self.render(stylesheets, enable_hinting=True)
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.write_image_surface(resolution))
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return surface
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def write_png(self, target=None, stylesheets=None, resolution=96):
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"""Paint the pages vertically to a single PNG image.
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There is no decoration around pages other than those specified in CSS
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with ``@page`` rules. The final image is as wide as the widest page.
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Each page is below the previous one, centered horizontally.
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This is a shortcut for calling :meth:`render`, then
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:meth:`Document.write_png() <document.Document.write_png>`.
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:param target:
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A filename, file-like object, or :obj:`None`.
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:param stylesheets:
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An optional list of user stylesheets. (See
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:ref:`stylesheet-origins`\.) The list’s elements are
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:class:`CSS` objects, filenames, URLs, or file-like objects.
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:type resolution: float
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:param resolution:
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The output resolution in PNG pixels per CSS inch. At 96 dpi
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(the default), PNG pixels match the CSS ``px`` unit.
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:returns:
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The image as byte string if :obj:`target` is not provided or
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:obj:`None`, otherwise :obj:`None` (the image is written to
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:obj:`target`.)
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"""
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png_bytes, _width, _height = (
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self.render(stylesheets, enable_hinting=True)
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.write_png(target, resolution))
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return png_bytes
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class CSS(object):
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"""Represents a CSS stylesheet parsed by tinycss.
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An instance is created in the same way as :class:`HTML`, except that
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the ``tree`` parameter is not available. All other parameters are the same.
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``CSS`` objects have no public attribute or method. They are only meant to
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be used in the :meth:`~HTML.write_pdf`, :meth:`~HTML.write_png` and
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:meth:`~HTML.render` methods of :class:`HTML` objects.
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"""
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def __init__(self, guess=None, filename=None, url=None, file_obj=None,
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string=None, encoding=None, base_url=None,
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url_fetcher=default_url_fetcher, _check_mime_type=False,
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media_type='print'):
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url_fetcher = wrap_url_fetcher(url_fetcher)
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source_type, source, base_url, protocol_encoding = _select_source(
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guess, filename, url, file_obj, string, tree=None,
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base_url=base_url, url_fetcher=url_fetcher,
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check_css_mime_type=_check_mime_type,)
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kwargs = dict(linking_encoding=encoding,
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protocol_encoding=protocol_encoding)
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if source_type == 'string':
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if isinstance(source, bytes):
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method = 'parse_stylesheet_bytes'
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else:
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# unicode, no encoding
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method = 'parse_stylesheet'
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kwargs.clear()
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else:
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# file_obj or filename
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method = 'parse_stylesheet_file'
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# TODO: do not keep this?
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self.stylesheet = getattr(PARSER, method)(source, **kwargs)
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self.base_url = base_url
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self.rules = list(preprocess_stylesheet(
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media_type, base_url, self.stylesheet.rules, url_fetcher))
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for error in self.stylesheet.errors:
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LOGGER.warn(error)
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def _select_source(guess=None, filename=None, url=None, file_obj=None,
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string=None, tree=None, base_url=None,
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url_fetcher=default_url_fetcher, check_css_mime_type=False):
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"""
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Check that only one input is not None, and return it with the
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normalized ``base_url``.
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"""
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if base_url is not None:
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base_url = ensure_url(base_url)
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nones = [guess is None, filename is None, url is None,
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file_obj is None, string is None, tree is None]
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if nones == [False, True, True, True, True, True]:
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if hasattr(guess, 'read'):
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type_ = 'file_obj'
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elif url_is_absolute(guess):
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type_ = 'url'
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else:
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type_ = 'filename'
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return _select_source(
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base_url=base_url, url_fetcher=url_fetcher,
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check_css_mime_type=check_css_mime_type,
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**{type_: guess})
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if nones == [True, False, True, True, True, True]:
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if base_url is None:
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base_url = path2url(filename)
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return 'filename', filename, base_url, None
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if nones == [True, True, False, True, True, True]:
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result = url_fetcher(url)
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if check_css_mime_type and result['mime_type'] != 'text/css':
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LOGGER.warn(
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'Unsupported stylesheet type %s for %s',
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result['mime_type'], result['redirected_url'])
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return 'string', '', base_url, None
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protocol_encoding = result.get('encoding')
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if base_url is None:
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base_url = result.get('redirected_url', url)
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if 'string' in result:
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return 'string', result['string'], base_url, protocol_encoding
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else:
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return 'file_obj', result['file_obj'], base_url, protocol_encoding
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if nones == [True, True, True, False, True, True]:
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if base_url is None:
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# filesystem file-like objects have a 'name' attribute.
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name = getattr(file_obj, 'name', None)
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# Some streams have a .name like '<stdin>', not a filename.
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if name and not name.startswith('<'):
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base_url = ensure_url(name)
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return 'file_obj', file_obj, base_url, None
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if nones == [True, True, True, True, False, True]:
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return 'string', string, base_url, None
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if nones == [True, True, True, True, True, False]:
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return 'tree', tree, base_url, None
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raise TypeError('Expected exactly one source, got ' + (
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', '.join(name for i, name in enumerate(
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'guess filename url file_obj string tree'.split()) if not nones[i]
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) or 'nothing'))
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# Work around circular imports.
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from .css import PARSER, preprocess_stylesheet
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from .html import find_base_url, HTML5_UA_STYLESHEET
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from .document import Document, Page
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