django-tgcms

A reusable Django app for building Telegram posts. Compose posts from blocks (heading, formatted text, photo, video) with a WYSIWYG editor embedded in Django admin. Post.render() returns a Bot API-ready payload, compose() merges blocks into ready-to-send messages — sending is entirely up to you.

No dependencies beyond Django. No bot logic, no HTTP calls.

Installation

pip install django-tgcms
# or
uv add django-tgcms

settings.py:

INSTALLED_APPS = [
    ...
    "tgcms",
]

Run migrations:

python manage.py migrate

Content — Django admin

Posts are edited in the standard Django admin at /admin/tgcms/post/. The change page shows a collapsible "Bot API payload" preview of render().

Block types (drag-and-drop reordering inside each post):

• heading — plain text title, sent bold
• text — formatted text: bold, italic, underline, strikethrough, spoiler, code, pre, blockquote, links
• photo / video — media asset + caption

MediaAsset (/admin/tgcms/mediaasset/) is a shared media registry. One asset can be referenced by any number of blocks across any number of posts. After the first Telegram send the telegram_file_id is cached on the asset — subsequent sends reuse it without re-uploading.

compose() — merged messages

render() gives you raw per-block payloads. compose() merges heading/text blocks into whole messages the way channels usually post:

from tgcms.compose import compose, CAPTION_LIMIT

chunks, media = compose(post)
# chunks: [(text, entities), ...] — headings become bold entities,
#          offsets recalculated in UTF-16 units, split at 4096
# media:  photo/video blocks in post order

Typical delivery strategy: one media block + one chunk that fits CAPTION_LIMIT → a single sendPhoto with caption_entities; otherwise send media, then each chunk via sendMessage with entities.

Bot integration

from tgcms.models import Post

post = Post.objects.prefetch_related("blocks__media").get(pk=post_id)
payload = post.render()
# {
#   "blocks": [
#     {"type": "heading", "text": "Title"},
#     {"type": "text", "text": "Hello!", "entities": [{"type": "bold", "offset": 0, "length": 5}]},
#     {"type": "photo", "media_asset_id": 3, "file": "AgACAgI...", "caption": "..."},
#   ]
# }

aiogram broadcast pattern:

from asgiref.sync import sync_to_async

async def send_post(bot, chat_id: int, post_id: int):
    post = await sync_to_async(
        Post.objects.prefetch_related("blocks__media").get
    )(pk=post_id)

    for block in post.blocks.all():
        data = block.render()

        if data["type"] == "heading":
            await bot.send_message(chat_id, f"<b>{data['text']}</b>", parse_mode="HTML")

        elif data["type"] == "text":
            await bot.send_message(chat_id, data["text"])

        elif data["type"] == "photo":
            msg = await bot.send_photo(
                chat_id,
                photo=data["file"],        # telegram_file_id, S3 URL, or local path
                caption=data.get("caption"),
            )
            # Cache file_id after first upload — all future renders return it
            if block.media and not block.media.telegram_file_id:
                await sync_to_async(block.media.cache_file_id)(msg.photo[-1].file_id)

        elif data["type"] == "video":
            msg = await bot.send_video(chat_id, video=data["file"], caption=data.get("caption"))
            if block.media and not block.media.telegram_file_id:
                await sync_to_async(block.media.cache_file_id)(msg.video.file_id)

Once cache_file_id() is called, block.media.source returns the cached telegram_file_id for every subsequent post that references the same asset.

Models

MediaAsset
  file              FileField — upload from disk
  file_url          URLField  — S3 / CDN link
  telegram_file_id  Cached after first send (read-only in admin)
  .source           Property: returns the best available file reference
  .cache_file_id()  Persists telegram_file_id; call once after the first send

Post
  title, status     draft / published
  .render()         Returns {"blocks": [...]}
  .mark_published() Sets status and published_at

Block               FK → Post, FK → MediaAsset (nullable)
  type              heading / text / photo / video
  order             Managed by drag-and-drop in admin
  text, entities    heading and text blocks
  media             FK → MediaAsset, photo and video blocks
  caption, caption_entities
  .render()         Returns one block in Bot API format

UTF-16 offsets

MessageEntity.offset and length are counted in UTF-16 code units, not Python characters. Non-BMP characters (e.g. 😀 U+1F600) occupy 2 units, not 1. All offset arithmetic in tgcms.formatting goes through utf16_len().

License

MIT