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Python Markdown
Python Markdown converts Markdown to HTML and can be used as a library or
called from the command line.
## Basic usage as a module:
import markdown
html = markdown.markdown(your_text_string)
See <> for more
information and instructions on how to extend the functionality of
Python Markdown. Read that before you try modifying this file.
## Authors and License
Started by [Manfred Stienstra]( Continued and
maintained by [Yuri Takhteyev](, [Waylan
Limberg]( and [Artem Yunusov](
Copyright 2007-2013 The Python Markdown Project (v. 1.7 and later)
Copyright 200? Django Software Foundation (OrderedDict implementation)
Copyright 2004, 2005, 2006 Yuri Takhteyev (v. 0.2-1.6b)
Copyright 2004 Manfred Stienstra (the original version)
License: BSD (see LICENSE for details).
from __future__ import absolute_import
from __future__ import unicode_literals
from .__version__ import version, version_info # noqa
import codecs
import sys
import logging
import warnings
import importlib
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
__all__ = ['Markdown', 'markdown', 'markdownFromFile']
logger = logging.getLogger('MARKDOWN')
class Markdown(object):
"""Convert Markdown to HTML."""
doc_tag = "div" # Element used to wrap document - later removed
option_defaults = {
'html_replacement_text': '[HTML_REMOVED]',
'tab_length': 4,
'enable_attributes': True,
'smart_emphasis': True,
'lazy_ol': True,
output_formats = {
'html': to_html_string,
'html4': to_html_string,
'html5': to_html_string,
'xhtml': to_xhtml_string,
'xhtml1': to_xhtml_string,
'xhtml5': to_xhtml_string,
ESCAPED_CHARS = ['\\', '`', '*', '_', '{', '}', '[', ']',
'(', ')', '>', '#', '+', '-', '.', '!']
def __init__(self, *args, **kwargs):
Creates a new Markdown instance.
Keyword arguments:
* extensions: A list of extensions.
If they are of type string, the module will be loaded.
If they are a subclass of markdown.Extension, they will be used
* extension_configs: Configuration settings for extensions.
* output_format: Format of output. Supported formats are:
* "xhtml1": Outputs XHTML 1.x. Default.
* "xhtml5": Outputs XHTML style tags of HTML 5
* "xhtml": Outputs latest supported version of XHTML
(currently XHTML 1.1).
* "html4": Outputs HTML 4
* "html5": Outputs HTML style tags of HTML 5
* "html": Outputs latest supported version of HTML
(currently HTML 4).
Note that it is suggested that the more specific formats ("xhtml1"
and "html4") be used as "xhtml" or "html" may change in the future
if it makes sense at that time.
* safe_mode: Deprecated! Disallow raw html. One of "remove", "replace"
or "escape".
* html_replacement_text: Deprecated! Text used when safe_mode is set
to "replace".
* tab_length: Length of tabs in the source. Default: 4
* enable_attributes: Enable the conversion of attributes. Default: True
* smart_emphasis: Treat `_connected_words_` intelligently Default: True
* lazy_ol: Ignore number of first item of ordered lists. Default: True
# For backward compatibility, loop through old positional args
pos = ['extensions', 'extension_configs', 'safe_mode', 'output_format']
for c, arg in enumerate(args):
if pos[c] not in kwargs:
kwargs[pos[c]] = arg
if c+1 == len(pos): # pragma: no cover
# ignore any additional args
if len(args):
warnings.warn('Positional arguments are deprecated in Markdown. '
'Use keyword arguments only.',
# Loop through kwargs and assign defaults
for option, default in self.option_defaults.items():
setattr(self, option, kwargs.get(option, default))
self.safeMode = kwargs.get('safe_mode', False)
if self.safeMode and 'enable_attributes' not in kwargs:
# Disable attributes in safeMode when not explicitly set
self.enable_attributes = False
if 'safe_mode' in kwargs:
warnings.warn('"safe_mode" is deprecated in Python-Markdown. '
'Use an HTML sanitizer (like '
'Bleach '
'if you are parsing untrusted markdown text. '
'See the 2.6 release notes for more info',
if 'html_replacement_text' in kwargs:
warnings.warn('The "html_replacement_text" keyword is '
'deprecated along with "safe_mode".',
self.registeredExtensions = []
self.docType = ""
self.stripTopLevelTags = True
self.references = {}
self.htmlStash = util.HtmlStash()
self.registerExtensions(extensions=kwargs.get('extensions', []),
configs=kwargs.get('extension_configs', {}))
self.set_output_format(kwargs.get('output_format', 'xhtml1'))
def build_parser(self):
""" Build the parser from the various parts. """
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, configs):
Register extensions with this instance of Markdown.
Keyword arguments:
* extensions: A list of extensions, which can either
be strings or objects. See the docstring on Markdown.
* configs: A dictionary mapping module names to config options.
for ext in extensions:
if isinstance(ext, util.string_type):
ext = self.build_extension(ext, configs.get(ext, {}))
if isinstance(ext, Extension):
ext.extendMarkdown(self, globals())
'Successfully loaded extension "%s.%s".'
% (ext.__class__.__module__, ext.__class__.__name__)
elif ext is not None:
raise TypeError(
'Extension "%s.%s" must be of type: "markdown.Extension"'
% (ext.__class__.__module__, ext.__class__.__name__))
return self
def build_extension(self, ext_name, configs):
"""Build extension by name, then return the module.
The extension name may contain arguments as part of the string in the
following format: "extname(key1=value1,key2=value2)"
configs = dict(configs)
# Parse extensions config params (ignore the order)
pos = ext_name.find("(") # find the first "("
if pos > 0:
ext_args = ext_name[pos+1:-1]
ext_name = ext_name[:pos]
pairs = [x.split("=") for x in ext_args.split(",")]
configs.update([(x.strip(), y.strip()) for (x, y) in pairs])
warnings.warn('Setting configs in the Named Extension string is '
'deprecated. It is recommended that you '
'pass an instance of the extension class to '
'Markdown or use the "extension_configs" keyword. '
'The current behavior will raise an error in version 2.7. '
'See the Release Notes for Python-Markdown version '
'2.6 for more info.', DeprecationWarning)
# Get class name (if provided): ``
ext_name, class_name = ext_name.split(':', 1) \
if ':' in ext_name else (ext_name, '')
# Try loading the extension first from one place, then another
# Assume string uses dot syntax (``)
module = importlib.import_module(ext_name)
'Successfuly imported extension module "%s".' % ext_name
# For backward compat (until deprecation)
# check that this is an extension.
if ('.' not in ext_name and not (hasattr(module, 'makeExtension') or
(class_name and hasattr(module, class_name)))):
# We have a name conflict
# eg: extensions=['tables'] and PyTables is installed
raise ImportError
except ImportError:
# Preppend `markdown.extensions.` to name
module_name = '.'.join(['markdown.extensions', ext_name])
module = importlib.import_module(module_name)
'Successfuly imported extension module "%s".' %
warnings.warn('Using short names for Markdown\'s builtin '
'extensions is deprecated. Use the '
'full path to the extension with Python\'s dot '
'notation (eg: "%s" instead of "%s"). The '
'current behavior will raise an error in version '
'2.7. See the Release Notes for '
'Python-Markdown version 2.6 for more info.' %
(module_name, ext_name),
except ImportError:
# Preppend `mdx_` to name
module_name_old_style = '_'.join(['mdx', ext_name])
module = importlib.import_module(module_name_old_style)
'Successfuly imported extension module "%s".' %
warnings.warn('Markdown\'s behavior of prepending "mdx_" '
'to an extension name is deprecated. '
'Use the full path to the '
'extension with Python\'s dot notation '
'(eg: "%s" instead of "%s"). The current '
'behavior will raise an error in version 2.7. '
'See the Release Notes for Python-Markdown '
'version 2.6 for more info.' %
(module_name_old_style, ext_name),
except ImportError as e:
message = "Failed loading extension '%s' from '%s', '%s' " \
"or '%s'" % (ext_name, ext_name, module_name,
e.args = (message,) + e.args[1:]
if class_name:
# Load given class name from module.
return getattr(module, class_name)(**configs)
# Expect makeExtension() function to return a class.
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:]
def registerExtension(self, extension):
""" This gets called by the extension """
return self
def reset(self):
Resets all state variables so that we can start with a new text.
for extension in self.registeredExtensions:
if hasattr(extension, 'reset'):
return self
def set_output_format(self, format):
""" Set the output format for the class instance. """
self.output_format = format.lower()
self.serializer = self.output_formats[self.output_format]
except KeyError as e:
valid_formats = list(self.output_formats.keys())
message = 'Invalid Output Format: "%s". Use one of %s.' \
% (self.output_format,
'"' + '", "'.join(valid_formats) + '"')
e.args = (message,) + e.args[1:]
return self
def convert(self, source):
Convert markdown to serialized XHTML or HTML.
Keyword arguments:
* source: Source text as a Unicode string.
Markdown processing takes place in five steps:
1. A bunch of "preprocessors" munge the input text.
2. BlockParser() parses the high-level structural elements of the
pre-processed text into an ElementTree.
3. A bunch of "treeprocessors" are run against the ElementTree. One
such treeprocessor runs InlinePatterns against the ElementTree,
detecting inline markup.
4. Some post-processors are run against the text after the ElementTree
has been serialized into text.
5. The output is written to a string.
# Fixup the source text
if not source.strip():
return '' # a blank unicode string
source = util.text_type(source)
except UnicodeDecodeError as e:
# Customise error message while maintaining original trackback
e.reason += '. -- Note: Markdown only accepts unicode input!'
# Split into lines and run the line preprocessors.
self.lines = source.split("\n")
for prep in self.preprocessors.values():
self.lines =
# Parse the high-level elements.
root = self.parser.parseDocument(self.lines).getroot()
# Run the tree-processors
for treeprocessor in self.treeprocessors.values():
newRoot =
if newRoot is not None:
root = newRoot
# Serialize _properly_. Strip top-level tags.
output = self.serializer(root)
if self.stripTopLevelTags:
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: # pragma: no cover
if output.strip().endswith('<%s />' % self.doc_tag):
# We have an empty document
output = ''
# We have a serious problem
raise ValueError('Markdown failed to strip top-level '
'tags. Document=%r' % output.strip())
# Run the text post-processors
for pp in self.postprocessors.values():
output =
return output.strip()
def convertFile(self, input=None, output=None, encoding=None):
"""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' 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 /
Keyword 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, util.string_type):
input_file =, mode="r", encoding=encoding)
input_file = codecs.getreader(encoding)(input)
text =
text =
if not isinstance(text, util.text_type):
text = text.decode(encoding)
text = text.lstrip('\ufeff') # remove the byte-order mark
# Convert
html = self.convert(text)
# Write to file or stdout
if output:
if isinstance(output, util.string_type):
output_file =, "w",
writer = codecs.getwriter(encoding)
output_file = writer(output, errors="xmlcharrefreplace")
# Don't close here. User may want to write more.
# Encode manually and write bytes to stdout.
html = html.encode(encoding, "xmlcharrefreplace")
# Write bytes directly to buffer (Python 3).
except AttributeError:
# Probably Python 2, which works with bytes by default.
return self
Those are the two functions we really mean to export: markdown() and
def markdown(text, *args, **kwargs):
"""Convert a Markdown string to HTML and return HTML as a Unicode string.
This is a shortcut function for `Markdown` class to cover the most
basic use case. It initializes an instance of Markdown, loads the
necessary extensions and runs the parser on the given text.
Keyword arguments:
* text: Markdown formatted text as Unicode or ASCII string.
* Any arguments accepted by the Markdown class.
Returns: An HTML document as a string.
md = Markdown(*args, **kwargs)
return md.convert(text)
def markdownFromFile(*args, **kwargs):
"""Read markdown code from a file and write it to a file or a stream.
This is a shortcut function which initializes an instance of Markdown,
and calls the convertFile method rather than convert.
Keyword arguments:
* input: a file name or readable object.
* output: a file name or writable object.
* encoding: Encoding of input and output.
* Any arguments accepted by the Markdown class.
# For backward compatibility loop through positional args
pos = ['input', 'output', 'extensions', 'encoding']
c = 0
for arg in args:
if pos[c] not in kwargs:
kwargs[pos[c]] = arg
c += 1
if c == len(pos):
if len(args):
warnings.warn('Positional arguments are depreacted in '
'Markdown and will raise an error in version 2.7. '
'Use keyword arguments only.',
md = Markdown(**kwargs)
md.convertFile(kwargs.get('input', None),
kwargs.get('output', None),
kwargs.get('encoding', None))