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195 lines
7.0 KiB
Python
195 lines
7.0 KiB
Python
![]()
2 months ago
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# Add x/html serialization to `Elementree`
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# Taken from ElementTree 1.3 preview with slight modifications
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#
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# Copyright (c) 1999-2007 by Fredrik Lundh. All rights reserved.
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#
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# fredrik@pythonware.com
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# https://www.pythonware.com/
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#
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# --------------------------------------------------------------------
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# The ElementTree toolkit is
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#
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# Copyright (c) 1999-2007 by Fredrik Lundh
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#
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# By obtaining, using, and/or copying this software and/or its
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# associated documentation, you agree that you have read, understood,
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# and will comply with the following terms and conditions:
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#
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# Permission to use, copy, modify, and distribute this software and
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# its associated documentation for any purpose and without fee is
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# hereby granted, provided that the above copyright notice appears in
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# all copies, and that both that copyright notice and this permission
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# notice appear in supporting documentation, and that the name of
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# Secret Labs AB or the author not be used in advertising or publicity
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# pertaining to distribution of the software without specific, written
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# prior permission.
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#
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# SECRET LABS AB AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD
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# TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANT-
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# ABILITY AND FITNESS. IN NO EVENT SHALL SECRET LABS AB OR THE AUTHOR
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# BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY
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# DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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# WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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# ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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# OF THIS SOFTWARE.
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# --------------------------------------------------------------------
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"""
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Python-Markdown provides two serializers which render [`ElementTree.Element`][xml.etree.ElementTree.Element]
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objects to a string of HTML. Both functions wrap the same underlying code with only a few minor
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differences as outlined below:
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1. Empty (self-closing) tags are rendered as `<tag>` for HTML and as `<tag />` for XHTML.
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2. Boolean attributes are rendered as `attrname` for HTML and as `attrname="attrname"` for XHTML.
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"""
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from __future__ import annotations
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from xml.etree.ElementTree import ProcessingInstruction
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from xml.etree.ElementTree import Comment, ElementTree, Element, QName, HTML_EMPTY
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import re
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from typing import Callable, Literal, NoReturn
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__all__ = ['to_html_string', 'to_xhtml_string']
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RE_AMP = re.compile(r'&(?!(?:\#[0-9]+|\#x[0-9a-f]+|[0-9a-z]+);)', re.I)
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def _raise_serialization_error(text: str) -> NoReturn: # pragma: no cover
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raise TypeError(
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"cannot serialize {!r} (type {})".format(text, type(text).__name__)
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)
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def _escape_cdata(text) -> str:
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# escape character data
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try:
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# it's worth avoiding do-nothing calls for strings that are
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# shorter than 500 character, or so. assume that's, by far,
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# the most common case in most applications.
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if "&" in text:
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# Only replace & when not part of an entity
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text = RE_AMP.sub('&', text)
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if "<" in text:
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text = text.replace("<", "<")
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if ">" in text:
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text = text.replace(">", ">")
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return text
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except (TypeError, AttributeError): # pragma: no cover
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_raise_serialization_error(text)
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def _escape_attrib(text: str) -> str:
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# escape attribute value
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try:
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if "&" in text:
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# Only replace & when not part of an entity
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text = RE_AMP.sub('&', text)
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if "<" in text:
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text = text.replace("<", "<")
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if ">" in text:
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text = text.replace(">", ">")
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if "\"" in text:
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text = text.replace("\"", """)
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if "\n" in text:
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text = text.replace("\n", " ")
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return text
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except (TypeError, AttributeError): # pragma: no cover
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_raise_serialization_error(text)
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def _escape_attrib_html(text: str) -> str:
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# escape attribute value
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try:
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if "&" in text:
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# Only replace & when not part of an entity
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text = RE_AMP.sub('&', text)
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if "<" in text:
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text = text.replace("<", "<")
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if ">" in text:
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text = text.replace(">", ">")
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if "\"" in text:
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text = text.replace("\"", """)
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return text
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except (TypeError, AttributeError): # pragma: no cover
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_raise_serialization_error(text)
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def _serialize_html(write: Callable[[str], None], elem: Element, format: Literal["html", "xhtml"]) -> None:
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tag = elem.tag
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text = elem.text
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if tag is Comment:
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write("<!--%s-->" % _escape_cdata(text))
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elif tag is ProcessingInstruction:
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write("<?%s?>" % _escape_cdata(text))
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elif tag is None:
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if text:
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write(_escape_cdata(text))
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for e in elem:
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_serialize_html(write, e, format)
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else:
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namespace_uri = None
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if isinstance(tag, QName):
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# `QNAME` objects store their data as a string: `{uri}tag`
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if tag.text[:1] == "{":
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namespace_uri, tag = tag.text[1:].split("}", 1)
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else:
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raise ValueError('QName objects must define a tag.')
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write("<" + tag)
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items = elem.items()
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if items:
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items = sorted(items) # lexical order
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for k, v in items:
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if isinstance(k, QName):
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# Assume a text only `QName`
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k = k.text
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if isinstance(v, QName):
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# Assume a text only `QName`
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v = v.text
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else:
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v = _escape_attrib_html(v)
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if k == v and format == 'html':
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# handle boolean attributes
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write(" %s" % v)
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else:
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write(' {}="{}"'.format(k, v))
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if namespace_uri:
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write(' xmlns="%s"' % (_escape_attrib(namespace_uri)))
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if format == "xhtml" and tag.lower() in HTML_EMPTY:
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write(" />")
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else:
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write(">")
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if text:
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if tag.lower() in ["script", "style"]:
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write(text)
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else:
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write(_escape_cdata(text))
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for e in elem:
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_serialize_html(write, e, format)
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if tag.lower() not in HTML_EMPTY:
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write("</" + tag + ">")
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if elem.tail:
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write(_escape_cdata(elem.tail))
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def _write_html(root: Element, format: Literal["html", "xhtml"] = "html") -> str:
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assert root is not None
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data: list[str] = []
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write = data.append
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_serialize_html(write, root, format)
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return "".join(data)
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# --------------------------------------------------------------------
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# public functions
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def to_html_string(element: Element) -> str:
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""" Serialize element and its children to a string of HTML5. """
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return _write_html(ElementTree(element).getroot(), format="html")
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def to_xhtml_string(element: Element) -> str:
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""" Serialize element and its children to a string of XHTML. """
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return _write_html(ElementTree(element).getroot(), format="xhtml")
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