telegram-exporter

Export a Telegram chat's media to a WebDAV server, using far less local disk than the chat's total size.

run.sh runs tdl and rclone as a rolling pipeline: tdl downloads into a small staging directory while rclone concurrently moves finished files to WebDAV and deletes the local copies. Local disk only ever holds the files in flight plus one sync interval of throughput, so a multi-terabyte chat exports fine on a small disk. Telegram caps a single file at 2 GB (4 GB from premium uploaders), so a few dozen GB of staging covers the worst case regardless of chat size.

This is needed because tdl can only write to a local directory — it has no rclone integration and no remote destination of any kind (tdl dl -d takes a filesystem path; tdl --storage is its session database, not an output target). tdl downloads over MTProto with a user account, so Bot API limits do not apply: full history is readable and there is no 20 MB download cap.

Requirements

• tdl — https://docs.iyear.me/tdl/getting-started/installation/
• rclone — https://rclone.org/install/
• bash. On Windows, run under WSL or Git Bash.

Setup

Both steps are one-time.

# 1) log in to Telegram with your user account (phone + code + 2FA)
tdl login

# 2) create the WebDAV remote
rclone config create tg-webdav webdav \
  url=https://dav.example.com/remote.php/dav/files/you \
  vendor=other user=YOU pass=SECRET

rclone lsd tg-webdav:      # verify it works

Usage

./run.sh -r tg-webdav:tg-export -c @mygroup

That is the whole flow. It exports the chat's message metadata to export.json, then downloads and uploads concurrently until finished. Progress and warnings go to stderr; press Ctrl-C at any point and it stops cleanly.

Options

Flag	Meaning
-r REMOTE:PATH	Required. rclone destination, e.g. tg-webdav:tg-export
-c CHAT	Chat to export when the JSON does not exist yet: @username or a numeric chat id
-f FILE	Export JSON to download from (default export.json)
-d DIR	Staging directory (default ./staging)
-i SECONDS	Seconds between rclone sweeps (default 60)
-a AGE	rclone --min-age, a second guard against moving files still being written (default 2m)
-h	Help

Anything after -- is passed straight to tdl dl:

./run.sh -r tg-webdav:tg-export -- -t 4 -l 1      # calmer parallelism, fewer flood waits
./run.sh -r tg-webdav:tg-export -- -i mp4,mkv     # only these file extensions
./run.sh -r tg-webdav:tg-export -- -e jpg,png     # skip these file extensions

tdl defaults to -t 8 -l 4, which is aggressive; lower it if you hit flood waits on a large export.

Exporting a subset

Generate the JSON yourself when you want a narrower export, then point -f at it:

tdl chat export -c @mygroup -T id -i 1000,5000 --all --with-content -o part.json
./run.sh -r tg-webdav:tg-export -f part.json

tdl chat export takes -T time|id|last with -i as the range, and -f as an expression filter over message fields (-f - lists the available fields).

Resuming

Re-run the same command. Both legs resume independently and nothing is downloaded or uploaded twice.

Keep the same export.json between runs: --skip-same compares against the staging directory, which is empty once files have moved to WebDAV, so cross-run deduplication rests on tdl's own --continue tracking. If you must start from a fresh export, narrow it to the missing message-id range (-T id -i <last>,<max>) rather than re-downloading everything.

What it guards against

• Partial uploads. tdl writes <name>.tmp and renames on completion, so every sweep excludes *.tmp. Age alone is not a completion signal: a download stalled by a flood wait stops touching its .tmp, which would then be uploaded half-written and lose its resume point.
• Directories vanishing under tdl. --delete-empty-src-dirs runs only in the final sweep, and the staging directory is recreated after every sweep. Removing a directory under a running tdl makes it fail to create its next file.
• Orphaned downloads. tdl is stopped on exit, Ctrl-C, or SIGTERM, so no download keeps running after the script is gone.
• A failed run looking finished. The unrestricted final sweep happens only after tdl exits 0. An interrupted or crashed run gets the age-guarded sweep and keeps staging for the next attempt.
• A dead remote filling the disk. Five consecutive rclone failures abort the run instead of letting staging grow unbounded.

Exit codes: 0 success, 2 usage error, 3 rclone failure, 130/143 interrupted, anything else is tdl's own exit code.

Limits

• Streaming with no staging at all (piping download chunks straight into a WebDAV PUT) is not possible with tdl and would require custom code.
• The script is bash; the two tools it drives are cross-platform, but Windows needs WSL or Git Bash.