Pelican plugin that adjusts markdown YAML front matter.

fixup_metayaml.py

# Pelican https://pypi.org/project/pelican/ plugin that adjusts markdown 
# YAML front matter created by Netlify CMS https://www.netlifycms.org/ et al.
# to be handled correctly as metadata in pelican.
# This plugin requires PyYAML https://pypi.org/project/PyYAML/ .

import io
import datetime
import yaml
from pelican import signals
from markdown import Markdown
from pelican.readers import MarkdownReader
from pelican.utils import pelican_open

def fixup_yaml(str_in):
    lines = str_in.split("\n")
    yaml_block = []

    line = lines.pop(0)

    if line == "---":
        while lines:
            line = lines.pop(0)
            if line == "---":
                break
            yaml_block.append(line)

    else:
        lines.insert(0, line)

    if yaml_block:
        meta_data = io.StringIO()
        print("---", file=meta_data)
        for k, v in yaml.safe_load(io.StringIO("\n".join(yaml_block))).items():
            if isinstance(v, datetime.datetime):
                v = v.strftime('%Y-%m-%dT%H:%M:%S.%f')[:-3] + 'Z'
            print(f"{k}: {v}", file=meta_data)
        print("---", file=meta_data)
        meta_data = meta_data.getvalue()
    else:
        meta_data = ""

    return meta_data + "\n".join(lines)


class FixupMetaYamlReader(MarkdownReader):
    def read(self, source_path):
        self._source_path = source_path
        self._md = Markdown(**self.settings['MARKDOWN'])
        with pelican_open(source_path) as text:
            text = fixup_yaml(text)
            content = self._md.convert(text)

        if hasattr(self._md, 'Meta'):
            metadata = self._parse_metadata(self._md.Meta)
        else:
            metadata = {}
        return content, metadata


def add_reader(readers):
    for k in MarkdownReader.file_extensions:
        readers.reader_classes[k] = FixupMetaYamlReader

def register():
    signals.readers_init.connect(add_reader)