Current File : //lib/python3/dist-packages/markdown/core.py
# Python Markdown
# A Python implementation of John Gruber's Markdown.
# Documentation: https://python-markdown.github.io/
# GitHub: https://github.com/Python-Markdown/markdown/
# PyPI: https://pypi.org/project/Markdown/
# Started by Manfred Stienstra (http://www.dwerg.net/).
# Maintained for a few years by Yuri Takhteyev (http://www.freewisdom.org).
# Currently maintained by Waylan Limberg (https://github.com/waylan),
# Dmitry Shachnev (https://github.com/mitya57) and Isaac Muse (https://github.com/facelessuser).
# Copyright 2007-2023 The Python Markdown Project (v. 1.7 and later)
# Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
# Copyright 2004 Manfred Stienstra (the original version)
# License: BSD (see LICENSE.md for details).
from __future__ import annotations
import codecs
import sys
import logging
import importlib
from typing import TYPE_CHECKING, Any, BinaryIO, Callable, ClassVar, Mapping, Sequence
from . import util
from .preprocessors import build_preprocessors
from .blockprocessors import build_block_parser
from .treeprocessors import build_treeprocessors
from .inlinepatterns import build_inlinepatterns
from .postprocessors import build_postprocessors
from .extensions import Extension
from .serializers import to_html_string, to_xhtml_string
from .util import BLOCK_LEVEL_ELEMENTS
if TYPE_CHECKING: # pragma: no cover
from xml.etree.ElementTree import Element
__all__ = ['Markdown', 'markdown', 'markdownFromFile']
logger = logging.getLogger('MARKDOWN')
class Markdown:
"""
A parser which converts Markdown to HTML.
Attributes:
Markdown.tab_length (int): The number of spaces which correspond to a single tab. Default: `4`.
Markdown.ESCAPED_CHARS (list[str]): List of characters which get the backslash escape treatment.
Markdown.block_level_elements (list[str]): List of HTML tags which get treated as block-level elements.
See [`markdown.util.BLOCK_LEVEL_ELEMENTS`][] for the full list of elements.
Markdown.registeredExtensions (list[Extension]): List of extensions which have called
[`registerExtension`][markdown.Markdown.registerExtension] during setup.
Markdown.doc_tag (str): Element used to wrap document. Default: `div`.
Markdown.stripTopLevelTags (bool): Indicates whether the `doc_tag` should be removed. Default: 'True'.
Markdown.references (dict[str, tuple[str, str]]): A mapping of link references found in a parsed document
where the key is the reference name and the value is a tuple of the URL and title.
Markdown.htmlStash (util.HtmlStash): The instance of the `HtmlStash` used by an instance of this class.
Markdown.output_formats (dict[str, Callable[xml.etree.ElementTree.Element]]): A mapping of known output
formats by name and their respective serializers. Each serializer must be a callable which accepts an
[`Element`][xml.etree.ElementTree.Element] and returns a `str`.
Markdown.output_format (str): The output format set by
[`set_output_format`][markdown.Markdown.set_output_format].
Markdown.serializer (Callable[xml.etree.ElementTree.Element]): The serializer set by
[`set_output_format`][markdown.Markdown.set_output_format].
Markdown.preprocessors (util.Registry): A collection of [`preprocessors`][markdown.preprocessors].
Markdown.parser (blockparser.BlockParser): A collection of [`blockprocessors`][markdown.blockprocessors].
Markdown.inlinePatterns (util.Registry): A collection of [`inlinepatterns`][markdown.inlinepatterns].
Markdown.treeprocessors (util.Registry): A collection of [`treeprocessors`][markdown.treeprocessors].
Markdown.postprocessors (util.Registry): A collection of [`postprocessors`][markdown.postprocessors].
"""
doc_tag = "div" # Element used to wrap document - later removed
output_formats: ClassVar[dict[str, Callable[[Element], str]]] = {
'html': to_html_string,
'xhtml': to_xhtml_string,
}
"""
A mapping of known output formats by name and their respective serializers. Each serializer must be a
callable which accepts an [`Element`][xml.etree.ElementTree.Element] and returns a `str`.
"""
def __init__(self, **kwargs):
"""
Creates a new Markdown instance.
Keyword Arguments:
extensions (list[Extension | str]): A list of extensions.
If an item is an instance of a subclass of [`markdown.extensions.Extension`][],
the instance will be used as-is. If an item is of type `str`, it is passed
to [`build_extension`][markdown.Markdown.build_extension] with its corresponding
`extension_configs` and the returned instance of [`markdown.extensions.Extension`][]
is used.
extension_configs (dict[str, dict[str, Any]]): Configuration settings for extensions.
output_format (str): Format of output. Supported formats are:
* `xhtml`: Outputs XHTML style tags. Default.
* `html`: Outputs HTML style tags.
tab_length (int): Length of tabs in the source. Default: `4`
"""
self.tab_length: int = kwargs.get('tab_length', 4)
self.ESCAPED_CHARS: list[str] = [
'\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '>', '#', '+', '-', '.', '!'
]
""" List of characters which get the backslash escape treatment. """
self.block_level_elements: list[str] = BLOCK_LEVEL_ELEMENTS.copy()
self.registeredExtensions: list[Extension] = []
self.docType = "" # TODO: Maybe delete this. It does not appear to be used anymore.
self.stripTopLevelTags: bool = True
self.build_parser()
self.references: dict[str, tuple[str, str]] = {}
self.htmlStash: util.HtmlStash = util.HtmlStash()
self.registerExtensions(extensions=kwargs.get('extensions', []),
configs=kwargs.get('extension_configs', {}))
self.set_output_format(kwargs.get('output_format', 'xhtml'))
self.reset()
def build_parser(self) -> Markdown:
"""
Build the parser from the various parts.
Assigns a value to each of the following attributes on the class instance:
* **`Markdown.preprocessors`** ([`Registry`][markdown.util.Registry]) -- A collection of
[`preprocessors`][markdown.preprocessors].
* **`Markdown.parser`** ([`BlockParser`][markdown.blockparser.BlockParser]) -- A collection of
[`blockprocessors`][markdown.blockprocessors].
* **`Markdown.inlinePatterns`** ([`Registry`][markdown.util.Registry]) -- A collection of
[`inlinepatterns`][markdown.inlinepatterns].
* **`Markdown.treeprocessors`** ([`Registry`][markdown.util.Registry]) -- A collection of
[`treeprocessors`][markdown.treeprocessors].
* **`Markdown.postprocessors`** ([`Registry`][markdown.util.Registry]) -- A collection of
[`postprocessors`][markdown.postprocessors].
This method could be redefined in a subclass to build a custom parser which is made up of a different
combination of processors and patterns.
"""
self.preprocessors = build_preprocessors(self)
self.parser = build_block_parser(self)
self.inlinePatterns = build_inlinepatterns(self)
self.treeprocessors = build_treeprocessors(self)
self.postprocessors = build_postprocessors(self)
return self
def registerExtensions(
self,
extensions: Sequence[Extension | str],
configs: Mapping[str, dict[str, Any]]
) -> Markdown:
"""
Load a list of extensions into an instance of the `Markdown` class.
Arguments:
extensions (list[Extension | str]): A list of extensions.
If an item is an instance of a subclass of [`markdown.extensions.Extension`][],
the instance will be used as-is. If an item is of type `str`, it is passed
to [`build_extension`][markdown.Markdown.build_extension] with its corresponding `configs` and the
returned instance of [`markdown.extensions.Extension`][] is used.
configs (dict[str, dict[str, Any]]): Configuration settings for extensions.
"""
for ext in extensions:
if isinstance(ext, str):
ext = self.build_extension(ext, configs.get(ext, {}))
if isinstance(ext, Extension):
ext.extendMarkdown(self)
logger.debug(
'Successfully loaded extension "%s.%s".'
% (ext.__class__.__module__, ext.__class__.__name__)
)
elif ext is not None:
raise TypeError(
'Extension "{}.{}" must be of type: "{}.{}"'.format(
ext.__class__.__module__, ext.__class__.__name__,
Extension.__module__, Extension.__name__
)
)
return self
def build_extension(self, ext_name: str, configs: Mapping[str, Any]) -> Extension:
"""
Build extension from a string name, then return an instance using the given `configs`.
Arguments:
ext_name: Name of extension as a string.
configs: Configuration settings for extension.
Returns:
An instance of the extension with the given configuration settings.
First attempt to load an entry point. The string name must be registered as an entry point in the
`markdown.extensions` group which points to a subclass of the [`markdown.extensions.Extension`][] class.
If multiple distributions have registered the same name, the first one found is returned.
If no entry point is found, assume dot notation (`path.to.module:ClassName`). Load the specified class and
return an instance. If no class is specified, import the module and call a `makeExtension` function and return
the [`markdown.extensions.Extension`][] instance returned by that function.
"""
configs = dict(configs)
entry_points = [ep for ep in util.get_installed_extensions() if ep.name == ext_name]
if entry_points:
ext = entry_points[0].load()
return ext(**configs)
# Get class name (if provided): `path.to.module:ClassName`
ext_name, class_name = ext_name.split(':', 1) if ':' in ext_name else (ext_name, '')
try:
module = importlib.import_module(ext_name)
logger.debug(
'Successfully imported extension module "%s".' % ext_name
)
except ImportError as e:
message = 'Failed loading extension "%s".' % ext_name
e.args = (message,) + e.args[1:]
raise
if class_name:
# Load given class name from module.
return getattr(module, class_name)(**configs)
else:
# Expect `makeExtension()` function to return a class.
try:
return module.makeExtension(**configs)
except AttributeError as e:
message = e.args[0]
message = "Failed to initiate extension " \
"'%s': %s" % (ext_name, message)
e.args = (message,) + e.args[1:]
raise
def registerExtension(self, extension: Extension) -> Markdown:
"""
Register an extension as having a resettable state.
Arguments:
extension: An instance of the extension to register.
This should get called once by an extension during setup. A "registered" extension's
`reset` method is called by [`Markdown.reset()`][markdown.Markdown.reset]. Not all extensions have or need a
resettable state, and so it should not be assumed that all extensions are "registered."
"""
self.registeredExtensions.append(extension)
return self
def reset(self) -> Markdown:
"""
Resets all state variables to prepare the parser instance for new input.
Called once upon creation of a class instance. Should be called manually between calls
to [`Markdown.convert`][markdown.Markdown.convert].
"""
self.htmlStash.reset()
self.references.clear()
for extension in self.registeredExtensions:
if hasattr(extension, 'reset'):
extension.reset()
return self
def set_output_format(self, format: str) -> Markdown:
"""
Set the output format for the class instance.
Arguments:
format: Must be a known value in `Markdown.output_formats`.
"""
self.output_format = format.lower().rstrip('145') # ignore number
try:
self.serializer = self.output_formats[self.output_format]
except KeyError as e:
valid_formats = list(self.output_formats.keys())
valid_formats.sort()
message = 'Invalid Output Format: "%s". Use one of %s.' \
% (self.output_format,
'"' + '", "'.join(valid_formats) + '"')
e.args = (message,) + e.args[1:]
raise
return self
# Note: the `tag` argument is type annotated `Any` as ElementTree uses many various objects as tags.
# As there is no standardization in ElementTree, the type of a given tag is unpredictable.
def is_block_level(self, tag: Any) -> bool:
"""
Check if the given `tag` is a block level HTML tag.
Returns `True` for any string listed in `Markdown.block_level_elements`. A `tag` which is
not a string always returns `False`.
"""
if isinstance(tag, str):
return tag.lower().rstrip('/') in self.block_level_elements
# Some ElementTree tags are not strings, so return False.
return False
def convert(self, source: str) -> str:
"""
Convert a Markdown string to a string in the specified output format.
Arguments:
source: Markdown formatted text as Unicode or ASCII string.
Returns:
A string in the specified output format.
Markdown parsing takes place in five steps:
1. A bunch of [`preprocessors`][markdown.preprocessors] munge the input text.
2. A [`BlockParser`][markdown.blockparser.BlockParser] parses the high-level structural elements of the
pre-processed text into an [`ElementTree`][xml.etree.ElementTree.ElementTree] object.
3. A bunch of [`treeprocessors`][markdown.treeprocessors] are run against the
[`ElementTree`][xml.etree.ElementTree.ElementTree] object. One such `treeprocessor`
([`markdown.treeprocessors.InlineProcessor`][]) runs [`inlinepatterns`][markdown.inlinepatterns]
against the [`ElementTree`][xml.etree.ElementTree.ElementTree] object, parsing inline markup.
4. Some [`postprocessors`][markdown.postprocessors] are run against the text after the
[`ElementTree`][xml.etree.ElementTree.ElementTree] object has been serialized into text.
5. The output is returned as a string.
"""
# Fix up the source text
if not source.strip():
return '' # a blank Unicode string
try:
source = str(source)
except UnicodeDecodeError as e: # pragma: no cover
# Customize error message while maintaining original traceback
e.reason += '. -- Note: Markdown only accepts Unicode input!'
raise
# Split into lines and run the line preprocessors.
self.lines = source.split("\n")
for prep in self.preprocessors:
self.lines = prep.run(self.lines)
# Parse the high-level elements.
root = self.parser.parseDocument(self.lines).getroot()
# Run the tree-processors
for treeprocessor in self.treeprocessors:
newRoot = treeprocessor.run(root)
if newRoot is not None:
root = newRoot
# Serialize _properly_. Strip top-level tags.
output = self.serializer(root)
if self.stripTopLevelTags:
try:
start = output.index(
'<%s>' % self.doc_tag) + len(self.doc_tag) + 2
end = output.rindex('</%s>' % self.doc_tag)
output = output[start:end].strip()
except ValueError as e: # pragma: no cover
if output.strip().endswith('<%s />' % self.doc_tag):
# We have an empty document
output = ''
else:
# We have a serious problem
raise ValueError('Markdown failed to strip top-level '
'tags. Document=%r' % output.strip()) from e
# Run the text post-processors
for pp in self.postprocessors:
output = pp.run(output)
return output.strip()
def convertFile(
self,
input: str | BinaryIO | None = None,
output: str | BinaryIO | None = None,
encoding: str | None = None,
) -> Markdown:
"""
Converts a Markdown file and returns the HTML as a Unicode string.
Decodes the file using the provided encoding (defaults to `utf-8`),
passes the file content to markdown, and outputs the HTML to either
the provided stream or the file with provided name, using the same
encoding as the source file. The
[`xmlcharrefreplace`](https://docs.python.org/3/library/codecs.html#error-handlers)
error handler is used when encoding the output.
**Note:** This is the only place that decoding and encoding of Unicode
takes place in Python-Markdown. (All other code is Unicode-in /
Unicode-out.)
Arguments:
input: File object or path. Reads from `stdin` if `None`.
output: File object or path. Writes to `stdout` if `None`.
encoding: Encoding of input and output files. Defaults to `utf-8`.
"""
encoding = encoding or "utf-8"
# Read the source
if input:
if isinstance(input, str):
input_file = codecs.open(input, mode="r", encoding=encoding)
else:
input_file = codecs.getreader(encoding)(input)
text = input_file.read()
input_file.close()
else:
text = sys.stdin.read()
text = text.lstrip('\ufeff') # remove the byte-order mark
# Convert
html = self.convert(text)
# Write to file or stdout
if output:
if isinstance(output, str):
output_file = codecs.open(output, "w",
encoding=encoding,
errors="xmlcharrefreplace")
output_file.write(html)
output_file.close()
else:
writer = codecs.getwriter(encoding)
output_file = writer(output, errors="xmlcharrefreplace")
output_file.write(html)
# Don't close here. User may want to write more.
else:
# Encode manually and write bytes to stdout.
html = html.encode(encoding, "xmlcharrefreplace")
sys.stdout.buffer.write(html)
return self
"""
EXPORTED FUNCTIONS
=============================================================================
Those are the two functions we really mean to export: `markdown()` and
`markdownFromFile()`.
"""
def markdown(text: str, **kwargs: Any) -> str:
"""
Convert a markdown string to HTML and return HTML as a Unicode string.
This is a shortcut function for [`Markdown`][markdown.Markdown] class to cover the most
basic use case. It initializes an instance of [`Markdown`][markdown.Markdown], loads the
necessary extensions and runs the parser on the given text.
Arguments:
text: Markdown formatted text as Unicode or ASCII string.
Keyword arguments:
**kwargs: Any arguments accepted by the Markdown class.
Returns:
A string in the specified output format.
"""
md = Markdown(**kwargs)
return md.convert(text)
def markdownFromFile(**kwargs: Any):
"""
Read Markdown text from a file and write output to a file or a stream.
This is a shortcut function which initializes an instance of [`Markdown`][markdown.Markdown],
and calls the [`convertFile`][markdown.Markdown.convertFile] method rather than
[`convert`][markdown.Markdown.convert].
Keyword arguments:
input (str | BinaryIO): A file name or readable object.
output (str | BinaryIO): A file name or writable object.
encoding (str): Encoding of input and output.
**kwargs: Any arguments accepted by the `Markdown` class.
"""
md = Markdown(**kwargs)
md.convertFile(kwargs.get('input', None),
kwargs.get('output', None),
kwargs.get('encoding', None))
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