#!/usr/bin/python
"""
HeaderID Extension for Python-Markdown
======================================
Auto-generate id attributes for HTML headers.
Basic usage:
>>> import markdown
>>> text = "# Some Header #"
>>> md = markdown.markdown(text, ['headerid'])
>>> md
u'
'
All header IDs are unique:
>>> text = '''
... #Header
... #Header
... #Header'''
>>> md = markdown.markdown(text, ['headerid'])
>>> md
u'\\n\\n'
To fit within a html template's hierarchy, set the header base level:
>>> text = '''
... #Some Header
... ## Next Level'''
>>> md = markdown.markdown(text, ['headerid(level=3)'])
>>> md
u'\\nNext Level
'
Works with inline markup.
>>> text = '#Some *Header* with [markup](http://example.com).'
>>> md = markdown.markdown(text, ['headerid'])
>>> md
u''
Turn off auto generated IDs:
>>> text = '''
... # Some Header
... # Another Header'''
>>> md = markdown.markdown(text, ['headerid(forceid=False)'])
>>> md
u'Some Header
\\nAnother Header
'
Use with MetaData extension:
>>> text = '''header_level: 2
... header_forceid: Off
...
... # A Header'''
>>> md = markdown.markdown(text, ['headerid', 'meta'])
>>> md
u'A Header
'
Copyright 2007-2011 [Waylan Limberg](http://achinghead.com/).
Project website:
Contact: markdown@freewisdom.org
License: BSD (see ../docs/LICENSE for details)
Dependencies:
* [Python 2.3+](http://python.org)
* [Markdown 2.0+](http://www.freewisdom.org/projects/python-markdown/)
"""
import markdown
from markdown.util import etree
import re
from string import ascii_lowercase, digits, punctuation
import logging
import unicodedata
logger = logging.getLogger('MARKDOWN')
IDCOUNT_RE = re.compile(r'^(.*)_([0-9]+)$')
def slugify(value, separator):
""" Slugify a string, to make it URL friendly. """
value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore')
value = unicode(re.sub('[^\w\s-]', '', value).strip().lower())
return re.sub('[%s\s]+' % separator, separator, value)
def unique(id, ids):
""" Ensure id is unique in set of ids. Append '_1', '_2'... if not """
while id in ids:
m = IDCOUNT_RE.match(id)
if m:
id = '%s_%d'% (m.group(1), int(m.group(2))+1)
else:
id = '%s_%d'% (id, 1)
ids.append(id)
return id
def itertext(elem):
""" Loop through all children and return text only.
Reimplements method of same name added to ElementTree in Python 2.7
"""
if elem.text:
yield elem.text
for e in elem:
for s in itertext(e):
yield s
if e.tail:
yield e.tail
class HeaderIdTreeprocessor(markdown.treeprocessors.Treeprocessor):
""" Assign IDs to headers. """
IDs = set()
def run(self, doc):
start_level, force_id = self._get_meta()
slugify = self.config['slugify']
sep = self.config['separator']
for elem in doc.getiterator():
if elem.tag in ['h1', 'h2', 'h3', 'h4', 'h5', 'h6']:
if force_id:
if "id" in elem.attrib:
id = elem.id
else:
id = slugify(''.join(itertext(elem)), sep)
elem.set('id', unique(id, self.IDs))
if start_level:
level = int(elem.tag[-1]) + start_level
if level > 6:
level = 6
elem.tag = 'h%d' % level
def _get_meta(self):
""" Return meta data suported by this ext as a tuple """
level = int(self.config['level']) - 1
force = self._str2bool(self.config['forceid'])
if hasattr(self.md, 'Meta'):
if self.md.Meta.has_key('header_level'):
level = int(self.md.Meta['header_level'][0]) - 1
if self.md.Meta.has_key('header_forceid'):
force = self._str2bool(self.md.Meta['header_forceid'][0])
return level, force
def _str2bool(self, s, default=False):
""" Convert a string to a booleen value. """
s = str(s)
if s.lower() in ['0', 'f', 'false', 'off', 'no', 'n']:
return False
elif s.lower() in ['1', 't', 'true', 'on', 'yes', 'y']:
return True
return default
class HeaderIdExtension (markdown.Extension):
def __init__(self, configs):
# set defaults
self.config = {
'level' : ['1', 'Base level for headers.'],
'forceid' : ['True', 'Force all headers to have an id.'],
'separator' : ['-', 'Word separator.'],
'slugify' : [slugify, 'Callable to generate anchors'],
}
for key, value in configs:
self.setConfig(key, value)
def extendMarkdown(self, md, md_globals):
md.registerExtension(self)
self.processor = HeaderIdTreeprocessor()
self.processor.md = md
self.processor.config = self.getConfigs()
# Replace existing hasheader in place.
md.treeprocessors.add('headerid', self.processor, '>inline')
def reset(self):
self.processor.IDs = []
def makeExtension(configs=None):
return HeaderIdExtension(configs=configs)
if __name__ == "__main__":
import doctest
doctest.testmod()