#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# flake8: noqa
# pylint: disable=broad-exception-raised, raise-missing-from, too-many-arguments, redefined-outer-name
# pylint: disable=multiple-statements, logging-fstring-interpolation, trailing-whitespace, line-too-long
# pylint: disable=broad-exception-caught, missing-function-docstring, missing-class-docstring
# pylint: disable=f-string-without-interpolation
# pylance: disable=reportMissingImports, reportMissingModuleSource
# mypy: disable-error-code="import-untyped"
import copy
import logging
import asyncio
import re
import time
from dataclasses import dataclass
from datetime import datetime, timezone
from typing import Optional
from feedgen.feed import FeedGenerator
from pyrogram import errors, Client
from pyrogram.types import Message
from post_parser import PostParser
from config import get_settings
from tg_throttle import tg_rpc_bounded
from sanitizer import sanitize_html
Config = get_settings()
logger = logging.getLogger(__name__)
@dataclass
class PreparedFeed:
"""Output of _prepare_feed_posts — everything both formatters need after
fetch -> enrich -> render -> filter -> sanitize."""
channel_username: str
channel_title: str # used by RSS metadata only
posts: list[dict] # rendered, filtered, sorted, SANITIZED
class ChannelNotFound(Exception):
"""Channel could not be resolved to a username; formatter -> create_error_feed."""
def __init__(self, channel_identifier):
# The prepared identifier (str or int), rendered into the error feed.
self.channel_identifier = channel_identifier
super().__init__(str(channel_identifier))
def _create_time_based_media_groups(messages: list[Message], merge_seconds: int = 5) -> list[Message]:
"""
Create media groups based on time difference between messages
Plain synchronous function (contains no await): runs inside the render thread
via _render_pipeline. Must not touch asyncio.
"""
# Deep-copy the input list to avoid mutating cached Message objects (the cache may
# reuse the same objects across calls with different merge_seconds values)
messages = copy.deepcopy(messages)
# Compute fallback once so all None-date messages get the same sort key (deterministic order)
_sort_fallback = datetime.now(timezone.utc)
messages_sorted = sorted(messages, key=lambda msg: msg.date or _sort_fallback) # type: ignore
cluster: list[Message] = []
last_msg_date: datetime = datetime.now(timezone.utc)
current_media_group_id: Optional[str] = None
for msg in messages_sorted:
if not cluster:
cluster.append(msg)
# Use current time as fallback when date is None
last_msg_date = msg.date or datetime.now(timezone.utc) # type: ignore
current_media_group_id = getattr(msg, "media_group_id", None)
continue
# Use current time as fallback when date is None to avoid TypeError in subtraction
msg_date = msg.date or datetime.now(timezone.utc)
time_diff = (msg_date - last_msg_date).total_seconds()
msg_media_group_id = getattr(msg, "media_group_id", None)
if time_diff <= merge_seconds:
if current_media_group_id:
msg.media_group_id = current_media_group_id # type: ignore
elif msg_media_group_id:
current_media_group_id = msg_media_group_id
for m in cluster:
m.media_group_id = current_media_group_id # type: ignore
cluster.append(msg)
# Use current time as fallback when date is None
last_msg_date = msg.date or datetime.now(timezone.utc) # type: ignore
else:
if len(cluster) >= 2 and not current_media_group_id:
dates = [m.date for m in cluster if m.date is not None]
if dates:
min_date = min(dates)
new_group_id = f"time_{min_date}"
for m in cluster:
m.media_group_id = new_group_id # type: ignore
cluster = [msg]
# Use current time as fallback when date is None
last_msg_date = msg.date or datetime.now(timezone.utc) # type: ignore
current_media_group_id = msg_media_group_id
if len(cluster) >= 2 and not current_media_group_id:
dates = [m.date for m in cluster if m.date is not None]
if dates:
min_date = min(dates)
new_group_id = f"time_{min_date}"
for m in cluster:
m.media_group_id = new_group_id # type: ignore
return messages_sorted
def _create_messages_groups(messages: list[Message]) -> list[list[Message]]:
"""
Process messages into formatted posts, handling media groups
Plain synchronous function (contains no await): runs inside the render thread.
"""
processing_groups: list[list[Message]] = []
media_groups: dict[str | int, list[Message]] = {}
# First pass - collect messages and organize into processing groups
for message in messages:
try:
# Skip service messages about pinned posts and new chat photos
if message.service:
if 'PINNED_MESSAGE' in str(message.service): continue
if 'NEW_CHAT_PHOTO' in str(message.service): continue
if 'NEW_CHAT_TITLE' in str(message.service): continue
if 'VIDEO_CHAT_STARTED' in str(message.service): continue
if 'VIDEO_CHAT_ENDED' in str(message.service): continue
if 'VIDEO_CHAT_SCHEDULED' in str(message.service): continue
if 'GROUP_CHAT_CREATED' in str(message.service): continue
if 'CHANNEL_CHAT_CREATED' in str(message.service): continue
if 'DELETE_CHAT_PHOTO' in str(message.service): continue
if message.media_group_id:
if message.media_group_id not in media_groups:
media_groups[message.media_group_id] = []
media_groups[message.media_group_id].append(message)
else:
processing_groups.append([message]) # Single message becomes its own processing group
except Exception as e:
username = message.chat.username if message.chat else 'unknown_chat'
logger.error(f"_create_messages_groups: channel {username}, message_id {message.id}, error {str(e)}")
continue
# Sort messages within media groups by message ID in descending order
for media_group in media_groups.values():
media_group.sort(key=lambda x: x.id, reverse=False)
processing_groups.append(media_group)
# Sort processing groups by date of first message in each group
processing_groups.sort(key=lambda group: group[0].date if group[0].date else datetime.now(timezone.utc), reverse=True)
return processing_groups
def _trim_messages_groups(messages_groups: list[list[Message]], limit: int):
"""
Trim messages groups to limit
Plain synchronous function (contains no await): runs inside the render thread.
"""
if len(messages_groups) > limit: # Trim groups if they exceed the specified limit
messages_groups = messages_groups[:limit]
return messages_groups
def _render_messages_groups(messages_groups: list[list[Message]],
post_parser: PostParser,
exclude_flags: str | None = None,
exclude_text: str | None = None):
"""
Render message groups into HTML format
Plain synchronous function (contains no await): runs inside the render thread.
Args:
messages_groups: List of message groups (each group is a list of messages)
post_parser: PostParser instance
exclude_flags: Comma-separated list of flags to exclude
exclude_text: Text to exclude from posts (comma-separated phrases)
Returns:
List of rendered posts
"""
rendered_posts = []
for group in messages_groups:
try:
if len(group) == 1: # Single message - simple case
one_message = group[0]
# Feed path: raw_message not needed and sanitize deferred to the per-post
# pass in _render_pipeline (both RSS and HTML), so each fragment is
# sanitized exactly once.
message_data = post_parser.process_message(one_message, include_raw=False, sanitize=False)
html_parts = [
f'{message_data["html"]["body"]}
',
f''
]
rendered_posts.append({
'html': '\n'.join(html_parts),
'date': message_data['date'],
'message_id': message_data['message_id'],
'title': message_data['html']['title'],
'text': message_data['text'],
'author': message_data['author'],
'flags': message_data['flags']
})
else: # Multiple messages in group - merge text and html body
processed_messages = [post_parser.process_message(msg, include_raw=False, sanitize=False) for msg in group]
# Determine the main message with the SAME criterion the processed dicts
# used: first message that has text or caption, else the first of the
# group. processed_messages[i] corresponds to group[i], so main_message
# (dict, for title/date/author) and main_raw (the real Message, for the
# footer) point at the same index.
main_idx = next((i for i, m in enumerate(group) if (m.text or m.caption)), 0)
main_raw = group[main_idx]
main_message = processed_messages[main_idx]
# Merge text fields from all messages
all_texts = [msg['text'] for msg in processed_messages if msg['text']]
combined_text = '\n'.join(all_texts)
# Merge html body sections from all messages
all_html_bodies = [msg['html']['body'] for msg in processed_messages if msg['html']['body']]
combined_html_body = '\n
\n'.join(all_html_bodies)
# Deterministic merged flags: first-seen order across the group, then
# 'merged' (registry §3.8 — replaces the hash-ordered list(set(...))).
merged_flags = list(dict.fromkeys(f for msg in processed_messages for f in msg['flags']))
merged_flags.append("merged")
# Render the merged footer DIRECTLY from the real main Message — no
# dict->mock round-trip. The raw Message carries its real reactions
# (custom emojis get their own span, registry §3.6) and its naive-local
# date (registry §3.7), matching a single post of the same message.
footer_html = post_parser.generate_html_footer(main_raw, flags_list=merged_flags)
html_parts = [
f'{combined_html_body}
',
f''
]
rendered_posts.append({
'html': '\n'.join(html_parts),
'date': main_message['date'],
'message_id': main_message['message_id'],
'title': main_message['html']['title'],
'text': combined_text,
'author': main_message['author'],
'flags': merged_flags
})
except Exception as e:
logger.error(f"message_group_rendering_error: error {str(e)}")
continue
# Filter posts by exclude_flags
if exclude_flags:
exclude_flag_list = [flag.strip() for flag in exclude_flags.split(',')] # Split comma-separated flags into list
filtered_posts = []
for post in rendered_posts:
# If "all" is specified and the post has any flags, exclude the post.
if "all" in exclude_flag_list and post['flags']:
continue
# Exclude post if any flag in the exclude list is present in the post's flags.
if any(flag in post['flags'] for flag in exclude_flag_list):
continue
filtered_posts.append(post)
rendered_posts = filtered_posts
# Filter posts by exclude_text
if exclude_text:
# Compile single regex pattern with UNICODE flag for proper handling of non-ASCII characters
exclude_pattern = re.compile(exclude_text.strip(), re.IGNORECASE | re.UNICODE)
filtered_posts = []
for post in rendered_posts:
# Check if pattern matches the post text
if not exclude_pattern.search(post['text']):
filtered_posts.append(post)
else:
logger.debug(f"excluded_post: message_id {post['message_id']}, pattern {exclude_pattern.pattern}")
rendered_posts = filtered_posts
# Sort by date; use 0.0 (epoch) as fallback for posts with None date to avoid TypeError
rendered_posts.sort(key=lambda x: x['date'] if x['date'] is not None else 0.0, reverse=True)
return rendered_posts
def _render_pipeline(messages: list[Message],
post_parser: PostParser,
limit: int,
exclude_flags: str | None,
exclude_text: str | None,
merge_seconds: int,
time_based_merge: bool,
channel: str | int):
"""
Full synchronous feed render pipeline (grouping + trimming + rendering + sanitize).
Runs entirely in a worker thread via a single asyncio.to_thread call. It contains
NO await, NO asyncio primitives, NO create_task/get_running_loop — all the CPU-heavy
work (deepcopy, grouping, rendering, bleach) happens here off the event loop.
Media file-id records are accumulated on post_parser._pending_media_ids and flushed
by the caller after this returns.
`channel` is used only for the sanitize log_context (grep-ability).
"""
if time_based_merge:
messages = _create_time_based_media_groups(messages, merge_seconds)
message_groups = _create_messages_groups(messages)
message_groups = _trim_messages_groups(message_groups, limit)
posts = _render_messages_groups(message_groups, post_parser, exclude_flags, exclude_text)
# Sanitize each surviving (post-filter) post exactly once, here in the worker
# thread — no per-post thread hop / per-post CSSSanitizer anymore. Per-post
# granularity means a failed post is html.escape()d in isolation instead of the
# whole feed (registry §3.5), and an unbalanced fragment is normalized within its
# OWN post rather than swallowing the following ones (registry §3.4). sanitize_html
# is fail-closed (registry §3.2). For the HTML path the
divider is joined in
# the formatter AFTER this, so it survives sanitize (registry §3.3).
for post in posts:
post['html'] = sanitize_html(
post['html'],
log_context=f"channel {channel}, message_id {post['message_id']}",
)
return posts
async def _prepare_feed_posts(channel: str | int,
client: Client,
*,
limit: int,
exclude_flags: str | None,
exclude_text: str | None,
merge_seconds: int,
history_limit: int,
enrich_replies: bool,
log_prefix: str) -> PreparedFeed:
"""Single code path feeding both feeds: validate -> resolve chat -> fetch history ->
(optionally) enrich replies -> render/filter/sort/sanitize in one worker thread. The
RSS/HTML formatters used to duplicate this ~80% verbatim; path differences are now
EXPLICIT parameters (history_limit: RSS over-fetches limit*2; enrich_replies: HTML-only;
log_prefix 'rss'|'html' keeps today's paired log-line names).
Raises ChannelNotFound (formatter -> create_error_feed), re-raises errors.FloodWait
for both the get_chat and the get_history path (§3.9; api_server -> HTTP 429), and
wraps any other resolution/history error in ValueError with unified text (§3.10).
"""
# 1) Validate limit.
if limit < 1:
raise ValueError(f"limit must be positive, got {limit}")
if limit > 200:
raise ValueError(f"limit cannot exceed 200, got {limit}")
post_parser = PostParser(client=client)
# 2) Resolve the chat. NOTE: keep `from tg_cache import ...` INSIDE this function —
# feed tests monkeypatch tg_cache and rely on late name resolution.
channel_info_start_time = time.time()
try:
channel = post_parser.channel_name_prepare(channel)
from tg_cache import cached_get_chat
channel_info = await cached_get_chat(post_parser.client, channel)
channel_title = channel_info.title or f"Telegram: {channel}"
channel_username = channel_info.username or (str(channel_info.id) if channel_info.id and str(channel_info.id).startswith('-100') else None)
if not channel_username:
# Prepared channel (which could be int) is carried into the error feed.
logger.warning(f"Could not get username for channel {channel}, using identifier for error feed.")
raise ChannelNotFound(channel)
except (errors.UsernameInvalid, errors.UsernameNotOccupied) as e:
logger.warning(f"Channel not found error for {channel}: {str(e)}")
raise ChannelNotFound(channel) from e
except errors.FloodWait:
# Let FloodWait bubble up to api_server.py, which returns HTTP 429 with Retry-After.
raise
except ChannelNotFound:
# The no-username branch above — not a resolution failure to wrap in ValueError.
raise
except Exception as e:
logger.error(f"Error during get_chat for channel '{channel}' (type: {type(channel)}): {str(e)}", exc_info=True)
raise ValueError(f"Failed to get chat info for {channel}: {str(e)}") from e
channel_info_elapsed = time.time() - channel_info_start_time
logger.debug(f"{log_prefix}_channel_info_timing: channel {channel}, retrieved in {channel_info_elapsed:.3f} seconds")
# 3) Fetch history.
messages_start_time = time.time()
try:
from tg_cache import cached_get_chat_history
messages = await cached_get_chat_history(post_parser.client, channel, limit=history_limit)
except errors.FloodWait:
# §3.9: FloodWait from history propagates -> HTTP 429 (previously wrapped -> 400).
raise
except Exception as e:
logger.error(f"Error during get_chat_history for channel '{channel}' (type: {type(channel)}): {str(e)}", exc_info=True)
raise ValueError(f"Failed to get chat history for {channel}: {str(e)}") from e
messages_elapsed = time.time() - messages_start_time
logger.debug(f"{log_prefix}_messages_retrieval_timing: channel {channel}, {len(messages)} messages retrieved in {messages_elapsed:.3f} seconds")
# 4) Optional reply enrichment (HTML-only today — deliberate, keeps RSS polling cheap).
if enrich_replies:
enrichment_start_time = time.time()
messages = await _reply_enrichment(client, messages)
enrichment_elapsed = time.time() - enrichment_start_time
logger.debug(f"{log_prefix}_reply_enrichment_timing: channel {channel}, replies enriched in {enrichment_elapsed:.3f} seconds")
# 5) Process messages into groups and render them. The whole grouping/trimming/
# rendering pipeline is CPU-heavy (deepcopy + per-message rendering) and contains no
# await, so run it in ONE worker thread to keep the event loop responsive.
processing_start_time = time.time()
try:
posts = await asyncio.to_thread(
_render_pipeline, messages, post_parser, limit,
exclude_flags, exclude_text, merge_seconds, Config['time_based_merge'],
channel,
)
finally:
# Persist media file-ids collected during rendering with a single bulk upsert —
# in a finally so a partial render still records what it collected (the flush is
# best-effort and swallows its own errors, so it cannot mask a render exception).
await post_parser._flush_pending_media_ids()
processing_elapsed = time.time() - processing_start_time
logger.debug(f"{log_prefix}_messages_processing_timing: channel {channel}, {len(posts)} posts processed in {processing_elapsed:.3f} seconds")
return PreparedFeed(channel_username=channel_username, channel_title=channel_title, posts=posts)
async def generate_channel_rss(channel: str | int,
client: Client,
limit: int = 20,
exclude_flags: str | None = None,
exclude_text: str | None = None,
merge_seconds: int = 5
) -> str:
"""
Generate RSS feed for channel using actual messages.
Thin formatter over the shared _prepare_feed_posts: it only turns the prepared,
sanitized posts into a feedgen RSS document. RSS over-fetches (history_limit=limit*2)
and skips reply enrichment (enrich_replies=False).
Args:
channel: Telegram channel name
client: Telegram client instance
limit: Maximum number of posts to include in the RSS feed
exclude_flags: Flags to exclude from the RSS feed
exclude_text: Text to exclude from posts
Returns:
RSS feed as string in XML format
"""
total_start_time = time.time()
base_url = Config['pyrogram_bridge_url']
try:
prepared = await _prepare_feed_posts(
channel, client,
limit=limit, exclude_flags=exclude_flags, exclude_text=exclude_text,
merge_seconds=merge_seconds, history_limit=limit * 2,
enrich_replies=False, log_prefix="rss",
)
channel_username = prepared.channel_username
channel_title = prepared.channel_title
final_posts = prepared.posts
fg = FeedGenerator()
fg.load_extension('dc')
# Set feed metadata
main_name = f"{channel_title} (@{channel_username})"
fg.title(main_name)
fg.link(href=f"https://t.me/{channel_username}", rel='alternate')
fg.description(f'Telegram channel {channel_username} RSS feed')
fg.language('ru')
fg.id(f"{base_url}/rss/{channel_username}") # Use username for feed ID consistency
# Generate feed entries
feed_gen_start_time = time.time()
# Log date range of posts being added to RSS
if final_posts:
dates = [datetime.fromtimestamp(post['date'], tz=timezone.utc) for post in final_posts if post.get('date')]
if dates:
oldest_date = min(dates)
newest_date = max(dates)
logger.info(f"rss_date_range: channel {channel}, oldest_post {oldest_date.isoformat()}, newest_post {newest_date.isoformat()}, total_posts {len(final_posts)}")
for post in final_posts:
fe = fg.add_entry()
fe.title(post['title'])
post_link = f"https://t.me/{channel_username}/{post['message_id']}"
fe.link(href=post_link)
fe.description(post['text'].replace('\n', ' '))
# post['html'] is already sanitized per-post inside _render_pipeline
# (single project-wide bleach config, fail-closed). No per-post thread
# hop / CSSSanitizer here anymore.
fe.content(content=post['html'], type='CDATA')
if post['date'] is not None:
pub_date = datetime.fromtimestamp(post['date'], tz=timezone.utc)
logger.debug(f"rss_entry_date: channel {channel}, message_id {post['message_id']}, timestamp {post['date']}, pub_date {pub_date.isoformat()}")
fe.pubDate(pub_date)
else:
# Date is None (e.g. service or deleted message) — fall back to current time
pub_date = datetime.now(tz=timezone.utc)
logger.warning(f"rss_entry_missing_date: channel {channel}, message_id {post['message_id']}, using current time as fallback")
fe.pubDate(pub_date)
fe.guid(post_link, permalink=True)
if post['author'] and post['author'] != main_name:
fe.author(name="", email=post['author'])
feed_gen_elapsed = time.time() - feed_gen_start_time
logger.debug(f"rss_feed_generation_timing: channel {channel}, feed generated in {feed_gen_elapsed:.3f} seconds")
# Serialize RSS in thread (feedgen may be CPU-heavy)
rss_feed = await asyncio.to_thread(fg.rss_str, pretty=True)
if isinstance(rss_feed, bytes):
return rss_feed.decode('utf-8')
total_elapsed = time.time() - total_start_time
logger.debug(f"rss_total_generation_timing: channel {channel}, total time {total_elapsed:.3f} seconds")
return rss_feed
except ChannelNotFound as e:
return create_error_feed(str(e.channel_identifier), base_url)
except Exception as e:
logger.error(f"generate_channel_rss: channel {channel}, error {str(e)}")
raise
async def _reply_enrichment(client: Client, messages: list[Message]) -> list[Message]:
"""
Enrich messages with reply-to messages.
Instead of one API call per message, replies are batched: all message IDs
that need enrichment are grouped by chat_id and fetched in a single
client.get_messages() call per chat_id.
"""
# Collect messages that need reply enrichment, grouped by chat_id
chat_messages: dict[int, list[Message]] = {}
for message in messages:
if message.reply_to_message_id and message.chat:
chat_id = message.chat.id
if chat_id not in chat_messages:
chat_messages[chat_id] = []
chat_messages[chat_id].append(message)
if not chat_messages:
# No messages with replies — return unchanged
return messages
# Build a lookup: {(chat_id, message_id): full_message} using one batch call per chat
reply_lookup: dict[tuple[int, int], Message] = {}
for chat_id, chat_msgs in chat_messages.items():
ids_to_fetch = [m.id for m in chat_msgs]
try:
# Throttle under the global RPC gate and bound the call via the shared
# tg_rpc_bounded so a hung get_messages cannot pin the gate.
async with tg_rpc_bounded(Config["tg_rpc_timeout"]):
fetched = await client.get_messages(chat_id, ids_to_fetch)
# get_messages may return a single Message or a list
if not isinstance(fetched, list):
fetched = [fetched]
for fm in fetched:
if fm and not getattr(fm, 'empty', False):
reply_lookup[(chat_id, fm.id)] = fm
except Exception as e:
logger.error(f"reply_enrichment_batch_error: chat_id {chat_id}, ids {ids_to_fetch}, error {str(e)}")
# Apply reply_to_message from lookup
for message in messages:
if message.reply_to_message_id and message.chat:
key = (message.chat.id, message.id)
full_message = reply_lookup.get(key)
if full_message and full_message.reply_to_message:
message.reply_to_message = full_message.reply_to_message
return messages
async def generate_channel_html(channel: str | int,
client: Client,
limit: int = 20,
exclude_flags: str | None = None,
exclude_text: str | None = None,
merge_seconds: int = 5
) -> str:
"""
Generate HTML feed for channel using actual messages.
Thin formatter over the shared _prepare_feed_posts: it only joins the prepared,
sanitized posts with the
divider. HTML fetches exactly `limit` messages and
enables reply enrichment (enrich_replies=True).
Args:
channel: Telegram channel name
client: Telegram client instance
limit: Maximum number of posts to include in the HTML feed
exclude_flags: Flags to exclude from the HTML feed
exclude_text: Text to exclude from posts
Returns:
HTML feed as string
"""
total_start_time = time.time()
base_url = Config['pyrogram_bridge_url']
try:
prepared = await _prepare_feed_posts(
channel, client,
limit=limit, exclude_flags=exclude_flags, exclude_text=exclude_text,
merge_seconds=merge_seconds, history_limit=limit,
enrich_replies=True, log_prefix="html",
)
final_posts = prepared.posts
# Generate HTML content.
html_gen_start_time = time.time()
# Each post is already sanitized per-post inside _render_pipeline. Join with the
#
divider AFTER sanitize so the divider survives (registry §3.3), and each
# post's DOM was normalized within its own fragment (registry §3.4). The join is
# a trivial string op — no worker thread needed.
html = '\n
\n'.join(post['html'] for post in final_posts)
html_gen_elapsed = time.time() - html_gen_start_time
logger.debug(f"html_generation_timing: channel {channel}, HTML generated in {html_gen_elapsed:.3f} seconds")
total_elapsed = time.time() - total_start_time
logger.debug(f"html_total_generation_timing: channel {channel}, total time {total_elapsed:.3f} seconds")
return html
except ChannelNotFound as e:
return create_error_feed(str(e.channel_identifier), base_url)
except Exception as e:
logger.error(f"html_generation_error: channel {channel}, error {str(e)}")
raise
def create_error_feed(channel: str | int, base_url: str) -> str:
"""
Create an empty RSS feed with metadata indicating an error when the channel is not found.
Args:
channel: Telegram channel name
base_url: Base URL for RSS feed
Returns:
Empty RSS feed as string in XML format.
"""
fg = FeedGenerator()
fg.title(f"Error: Channel @{channel} not found")
fg.link(href=f"https://t.me/{channel}", rel='alternate')
fg.description(f'Error: Telegram channel @{channel} does not exist')
fg.language('en')
fg.id(f"{base_url}/rss/{channel}")
fe = fg.add_entry()
fe.title("Channel not found")
# Use the original channel string identifier passed to the function for links/text
fe.link(href=f"https://t.me/{channel}")
error_html = f"The Telegram channel @{channel} does not exist or is not accessible.
"
fe.description(f"{error_html}")
fe.content(content=error_html, type='CDATA')
fe.pubDate(datetime.now(tz=timezone.utc))
fe.guid(f"https://t.me/{channel}", permalink=True)
rss_feed = fg.rss_str(pretty=True)
if isinstance(rss_feed, bytes):
return rss_feed.decode('utf-8')
return rss_feed