Check in a simple pure-python based Markdown previewer.

third_party/Python-Markdown/markdown/extensions/wikilinks.py

+'''
+WikiLinks Extension for Python-Markdown
+======================================
+
+Converts [[WikiLinks]] to relative links.
+
+See <https://pythonhosted.org/Markdown/extensions/wikilinks.html>
+for documentation.
+
+Original code Copyright [Waylan Limberg](http://achinghead.com/).
+
+All changes Copyright The Python Markdown Project
+
+License: [BSD](http://www.opensource.org/licenses/bsd-license.php)
+
+'''
+
+from __future__ import absolute_import
+from __future__ import unicode_literals
+from . import Extension
+from ..inlinepatterns import Pattern
+from ..util import etree
+import re
+
+
+def build_url(label, base, end):
+    """ Build a url from the label, a base, and an end. """
+    clean_label = re.sub(r'([ ]+_)|(_[ ]+)|([ ]+)', '_', label)
+    return '%s%s%s' % (base, clean_label, end)
+
+
+class WikiLinkExtension(Extension):
+
+    def __init__(self, *args, **kwargs):
+        self.config = {
+            'base_url': ['/', 'String to append to beginning or URL.'],
+            'end_url': ['/', 'String to append to end of URL.'],
+            'html_class': ['wikilink', 'CSS hook. Leave blank for none.'],
+            'build_url': [build_url, 'Callable formats URL from label.'],
+        }
+
+        super(WikiLinkExtension, self).__init__(*args, **kwargs)
+
+    def extendMarkdown(self, md, md_globals):
+        self.md = md
+
+        # append to end of inline patterns
+        WIKILINK_RE = r'\[\[([\w0-9_ -]+)\]\]'
+        wikilinkPattern = WikiLinks(WIKILINK_RE, self.getConfigs())
+        wikilinkPattern.md = md
+        md.inlinePatterns.add('wikilink', wikilinkPattern, "<not_strong")
+
+
+class WikiLinks(Pattern):
+    def __init__(self, pattern, config):
+        super(WikiLinks, self).__init__(pattern)
+        self.config = config
+
+    def handleMatch(self, m):
+        if m.group(2).strip():
+            base_url, end_url, html_class = self._getMeta()
+            label = m.group(2).strip()
+            url = self.config['build_url'](label, base_url, end_url)
+            a = etree.Element('a')
+            a.text = label
+            a.set('href', url)
+            if html_class:
+                a.set('class', html_class)
+        else:
+            a = ''
+        return a
+
+    def _getMeta(self):
+        """ Return meta data or config data. """
+        base_url = self.config['base_url']
+        end_url = self.config['end_url']
+        html_class = self.config['html_class']
+        if hasattr(self.md, 'Meta'):
+            if 'wiki_base_url' in self.md.Meta:
+                base_url = self.md.Meta['wiki_base_url'][0]
+            if 'wiki_end_url' in self.md.Meta:
+                end_url = self.md.Meta['wiki_end_url'][0]
+            if 'wiki_html_class' in self.md.Meta:
+                html_class = self.md.Meta['wiki_html_class'][0]
+        return base_url, end_url, html_class
+
+
+def makeExtension(*args, **kwargs):
+    return WikiLinkExtension(*args, **kwargs)