forked from github.com/blag
120 lines
3.0 KiB
Python
120 lines
3.0 KiB
Python
"""Markdown Processing.
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This module contains the methods responsible for blag's markdown
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processing.
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"""
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from datetime import datetime
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import logging
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from urllib.parse import urlsplit, urlunsplit
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from markdown import Markdown
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from markdown.extensions import Extension
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from markdown.treeprocessors import Treeprocessor
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logger = logging.getLogger(__name__)
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def markdown_factory():
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"""Create a Markdown instance.
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This method exists only to ensure we use the same Markdown instance
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for tests as for the actual thing.
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Returns
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-------
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markdown.Markdown
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"""
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md = Markdown(
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extensions=[
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'meta', 'fenced_code', 'codehilite', 'smarty',
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MarkdownLinkExtension()
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],
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output_format='html5',
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)
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return md
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def convert_markdown(md, markdown):
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"""Convert markdown into html and extract meta data.
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Some meta data is treated special:
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* `date` is converted into datetime with local timezone
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* `tags` is interpreted as a comma-separeted list of strings.
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All strings are stripped and converted to lower case.
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Parameters
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----------
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md : markdown.Markdown instance
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markdown : str
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Returns
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-------
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str, dict :
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html and metadata
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"""
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md.reset()
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content = md.convert(markdown)
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meta = md.Meta
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# markdowns metadata consists as list of strings -- one item per
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# line. let's convert into single strings.
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for key, value in meta.items():
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value = '\n'.join(value)
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meta[key] = value
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# convert known metadata
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# date: datetime
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if 'date' in meta:
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meta['date'] = datetime.fromisoformat(meta['date'])
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meta['date'] = meta['date'].astimezone()
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# tags: list[str] and lower case
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if 'tags' in meta:
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tags = meta['tags'].split(',')
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tags = [t.lower() for t in tags]
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tags = [t.strip() for t in tags]
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meta['tags'] = tags
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return content, meta
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class MarkdownLinkTreeprocessor(Treeprocessor):
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"""Converts relative links to .md files to .html
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"""
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def run(self, root):
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for element in root.iter():
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if element.tag == 'a':
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url = element.get('href')
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converted = self.convert(url)
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element.set('href', converted)
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return root
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def convert(self, url):
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scheme, netloc, path, query, fragment = urlsplit(url)
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logger.debug(
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f'{url}: {scheme=} {netloc=} {path=} {query=} {fragment=}'
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)
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if (scheme or netloc or not path):
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return url
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if path.endswith('.md'):
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path = path[:-3] + '.html'
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url = urlunsplit((scheme, netloc, path, query, fragment))
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return url
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class MarkdownLinkExtension(Extension):
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"""markdown.extension that converts relative .md- to .html-links.
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"""
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def extendMarkdown(self, md):
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md.treeprocessors.register(
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MarkdownLinkTreeprocessor(md), 'mdlink', 0,
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)
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