summaryrefslogtreecommitdiff
path: root/markdown/extensions/headerid.py
blob: cf3df175a93a91a603fa7951541d6055ac8c1430 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
#!/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'])
    >>> print md
    <h1 id="some-header">Some Header</h1>

All header IDs are unique:

    >>> text = '''
    ... #Header
    ... #Header
    ... #Header'''
    >>> md = markdown.markdown(text, ['headerid'])
    >>> print md
    <h1 id="header">Header</h1>
    <h1 id="header_1">Header</h1>
    <h1 id="header_2">Header</h1>

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)'])
    >>> print md
    <h3 id="some-header">Some Header</h3>
    <h4 id="next-level">Next Level</h4>

Works with inline markup.

    >>> text = '#Some *Header* with [markup](http://example.com).'
    >>> md = markdown.markdown(text, ['headerid'])
    >>> print md
    <h1 id="some-header-with-markup">Some <em>Header</em> with <a href="http://example.com">markup</a>.</h1>

Turn off auto generated IDs:

    >>> text = '''
    ... # Some Header
    ... # Another Header'''
    >>> md = markdown.markdown(text, ['headerid(forceid=False)'])
    >>> print md
    <h1>Some Header</h1>
    <h1>Another Header</h1>

Use with MetaData extension:

    >>> text = '''header_level: 2
    ... header_forceid: Off
    ...
    ... # A Header'''
    >>> md = markdown.markdown(text, ['headerid', 'meta'])
    >>> print md
    <h2>A Header</h2>

Copyright 2007-2011 [Waylan Limberg](http://achinghead.com/).

Project website: <http://packages.python.org/Markdown/extensions/header_id.html>
Contact: markdown@freewisdom.org

License: BSD (see ../docs/LICENSE for details) 

Dependencies:
* [Python 2.3+](http://python.org)
* [Markdown 2.0+](http://packages.python.org/Markdown/)

"""

import markdown
import re
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 = re.sub('[^\w\s-]', '', value.decode('ascii')).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 or not id:
        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.add(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.get('id')
                    else:
                        id = slugify(u''.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()
        if 'attr_list' in md.treeprocessors.keys():
            # insert after attr_list treeprocessor
            md.treeprocessors.add('headerid', self.processor, '>attr_list')
        else:
            # insert after 'prettify' treeprocessor.
            md.treeprocessors.add('headerid', self.processor, '>prettify')

    def reset(self):
        self.processor.IDs = set()


def makeExtension(configs=None):
    return HeaderIdExtension(configs=configs)

if __name__ == "__main__":
    import doctest
    doctest.testmod()