datatracker/ietf/utils/hedgedoc.py

127 lines
3.7 KiB
Python

# Copyright The IETF Trust 2021, All Rights Reserved
# -*- coding: utf-8 -*-
"""HedgeDoc API utilities"""
import json
import requests
import subprocess
import debug # pyflakes: ignore
from urllib.parse import urljoin
from django.conf import settings
from ietf.utils.markdown import markdown
class Note:
base_url = settings.IETF_NOTES_URL
def __init__(self, id):
self.id = id
self.url = urljoin(self.base_url, self.id) # URL on notes site
self._metadata = None
self._preview = None
self._source = None
@classmethod
def preprocess_source(cls, raw_source):
"""Perform preprocessing on raw source input
Guaranteed to process input in the same way that the Note class processes
markdown source pulled from the notes site.
"""
return de_gfm(raw_source)
def get_source(self):
"""Retrieve markdown source from hedgedoc
Converts line breaks from GitHub Flavored Markdown (GFM) style to
to traditional markdown.
"""
if self._source is None:
try:
r = requests.get(
urljoin(self.base_url, f'{self.id}/download'),
allow_redirects=True,
timeout=settings.DEFAULT_REQUESTS_TIMEOUT,
)
except requests.RequestException as exc:
raise ServerNoteError from exc
if r.status_code != 200:
raise NoteNotFound
self._source = self.preprocess_source(r.text)
return self._source
def get_preview(self):
if self._preview is None:
self._preview = markdown(self.get_source())
return self._preview
def get_title(self):
try:
metadata = self._retrieve_metadata()
except NoteError:
metadata = {} # don't let an error retrieving the title prevent retrieval
return metadata.get('title', None)
def get_update_time(self):
try:
metadata = self._retrieve_metadata()
except NoteError:
metadata = {} # don't let an error retrieving the update timestamp prevent retrieval
return metadata.get('updatetime', None)
def _retrieve_metadata(self):
if self._metadata is None:
try:
r = requests.get(
urljoin(self.base_url, f'{self.id}/info'),
allow_redirects=True,
timeout=settings.DEFAULT_REQUESTS_TIMEOUT,
)
except requests.RequestException as exc:
raise ServerNoteError from exc
if r.status_code != 200:
raise NoteNotFound
try:
self._metadata = json.loads(r.content)
except json.JSONDecodeError:
raise InvalidNote
return self._metadata
def de_gfm(source: str):
"""Convert GFM line breaks to standard Markdown
Calls de-gfm from the kramdown-rfc2629 gem.
"""
result = subprocess.run(
[settings.DE_GFM_BINARY, "-4"],
capture_output=True,
input=source,
encoding='utf8',
check=True,
)
return result.stdout
class NoteError(Exception):
"""Base class for exceptions in this module"""
default_message = 'A note-related error occurred'
def __init__(self, *args, **kwargs):
if not args:
args = (self.default_message, )
super().__init__(*args)
class ServerNoteError(NoteError):
default_message = 'Could not reach the notes server'
class NoteNotFound(NoteError):
default_message = 'Note did not exist or could not be loaded'
class InvalidNote(NoteError):
default_message = 'Note data invalid'