# telegram-exporter Archive a Telegram chat's media to **any rclone remote** — S3, Google Drive, Dropbox, Backblaze B2, SFTP, WebDAV, pikpak, or anything else rclone supports — using far less local disk than the chat's total size. `tgexport` embeds [tdl](https://github.com/iyear/tdl) and [rclone](https://rclone.org/) as libraries and runs both halves in one process. Files are downloaded into a small staging directory and uploaded the moment each one finishes, so local disk only ever holds what is in flight. A multi-terabyte chat archives 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 exists because **tdl can only write to a local directory** — it has 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 - **Go 1.25+** to build, or a prebuilt binary. - **tdl** — only for `tdl login`. - **rclone** — only to configure a remote. Neither tool is invoked at run time; `tgexport` reads the session and config they write. ## Setup Both steps are one-time. ```bash tdl login # writes the Telegram session tgexport reads rclone config # define the destination remote go build -o tgexport ./cmd/tgexport ./tgexport doctor -r myremote:archive ``` `doctor` proves both halves work before a long run: it prints the logged-in account, resolves the destination, and reports free space. ### Build variants | Build | Backends | Size | |---|---|---| | `go build ./cmd/tgexport` | every rclone backend | ~92 MB | | `go build -tags slim ./cmd/tgexport` | pikpak only | ~49 MB | A backend that is not compiled in does not exist at run time, so use the default build unless the destination will never change. ## Usage ```bash ./tgexport sync -c CHAT -r REMOTE:PATH [options] ``` A run states what it found, what it is about to do, and then shows each file as it moves: ``` reading mychannel 12,000 messages read in 4m31s indexing PikPak root 'mychannel' 11,406 objects listed in 2m10s chat holds 12,000 media, 250.0 GiB archived 11,400 never fetched 600 wrong size 6 fetching 606 files, 79.0 GiB (largest 2.0 GiB) into PikPak root 'mychannel' staging ./staging, capped at 40.0 GiB concurrency 2 download(s) x 4 thread(s), 2 upload(s) ↓ total 26/606 files [=> ] 617.5 MiB / 79.0 GiB 2.5 MiB/s 8h47m ↑ total 24/606 files [=> ] 598.0 MiB / 79.0 GiB 2.4 MiB/s 8h58m ↓ …7890_4242_1000000000000000001.mp4 [=======> ] 41.2 MiB / 96.0 MiB 1.8 MiB/s ↑ …7890_4243_1000000000000000002.mp4 ⠹ uploading 1.9 GiB ``` The two legs are counted separately because they run at different speeds and fail for different reasons. They normally track a file or two apart; a widening gap means the remote is falling behind and staging is filling up. Redirected output gets the same two figures as plain periodic lines, plus one line per archived file, with no cursor movement — a captured log stays readable: ``` download 1,200/606 files, 45.0 GiB of 79.0 GiB, 76.8 MiB/s, ETA 7m33s upload 1,190/606 files, 44.2 GiB of 79.0 GiB, 75.4 MiB/s, ETA 7m53s ``` `CHAT` accepts a numeric id as printed by `tdl chat ls`, a username with or without `@`, or a `t.me`/`tg://` link. A Bot API `-100…` id is converted automatically. A link to a single *message* is refused — it names a message, not a chat. ```bash # archive a chat, capping staging at 40 GiB ./tgexport sync -c @mychannel -r gdrive:telegram/media -m 40G # check completeness without downloading anything ./tgexport verify -c @mychannel -r gdrive:telegram/media # list what the chat holds ./tgexport list -c @mychannel ``` ### Options | Flag | Default | Meaning | |---|---|---| | `-c` | — | chat id, username, or link (required) | | `-r` | — | rclone destination, `REMOTE:PATH` (required) | | `-d` | `./staging` | staging directory for files in flight | | `-m` | no cap | cap staging at a size, e.g. `40G` | | `--threads` | 4 | connections per file | | `--limit` | 2 | files downloading at once | | `--uploads` | 2 | files uploading at once | | `--min-free` | 5 | stop if the remote has fewer than this many GiB free, checked before and during the run | | `--limit-items` | 0 | stop after N files; for smoke tests | | `--confirm` | true | re-state each uploaded file to prove its size | | `--takeout` | true | use a takeout session | | `-n` | `default` | tdl session namespace | ### Exit codes | Code | Meaning | |---|---| | 0 | complete | | 1 | ran, but files remain — run again | | 2 | usage error | | 3 | remote or Telegram failure, including either leg refusing transfer after transfer | | 4 | stalled: files remain, none of which can ever be fetched | | 130 / 143 | interrupted (SIGINT / SIGTERM) | Only 1 is worth retrying. A driver looping until 0 should stop on anything else: 3 and 4 both mean the next pass would do exactly what this one did. ## How it works Re-running is the resume path. Each item is checked against a listing of the remote immediately before download, so an interrupted run picks up where it left off and a completed one downloads nothing. **Filenames.** Every file is stored as `{DialogID}_{MessageID}_{FileName}`, where `FileName` is exactly what Telegram reports. One function derives that string, and the same string is used both to ask whether the file is already archived and to write it — so the two can never disagree. A name that cannot survive that round trip is refused rather than rewritten: too long for the filesystem once `.part` is appended, not a single path element, or containing a character rclone's path encoder rewrites (control bytes, `DEL`, and the encoder's own escape character). Those files are reported under `unarchivable` and never counted as present. Rewriting them is what the next paragraph is about. That last point is the reason this program exists. Its predecessor derived the name twice: `tdl chat export` wrote the raw name into a JSON, while `tdl dl` rendered it through a template applying `filenamify`, which rewrites characters a filesystem rejects and collapses runs of `!`. A file whose name contained `!!` was looked up under one name and stored under another, so the verifier never found it and re-fetched it on every pass — forever, at 966 MB a time. Note the consequence: names are **not** run through `filenamify`, so they are not byte-compatible with what the old shell pipeline wrote. A file it stored under a rewritten name will not be recognised and gets fetched again. **Disk.** `-m` is a byte budget. A download reserves its own size before starting and releases it only once the upload is confirmed, so when the remote is slow the downloads pause on their own. The cap must exceed the largest single file, and a cap that does not is refused at startup rather than discovered as a hang. **Integrity.** A download is written to `.part` and renamed only once its size matches what Telegram reported, so a file without the suffix is always whole. Uploads are re-stated afterwards to prove they arrived at the right size, before the local copy is gone, and an object that turns out short is deleted rather than left under a name a later run would trust. `verify` compares stored sizes against what Telegram reports, so a truncated object is outstanding rather than "present". This is stricter than the shell verifier, which matched on name and non-zero size — on the archive this was built for it found six objects that had been counted complete for months, one of them 221 MiB standing in for a 2 GiB video. Re-running repairs them. **File references.** Telegram hands out a short-lived token with every file location, and a run over a large chat outlives the ones its walk collected — the lifetime is undocumented, but an observed run stopped just under two hours in with `FILE_REFERENCE_EXPIRED` on every remaining file. So each message is re-read for a live token immediately before its own download, which costs one round trip per transfer and needs no guess at how long a token lasts. Retry passes go through the same path, so a token that dies during a single very large transfer is replaced rather than replayed. The re-read has to describe the same file — same name, same length — or it is not the file this run recorded, and archiving it under that name would store the wrong bytes. A message that fails that check, or that has been deleted, or that no longer holds a file at all, is skipped and reported: nothing can be archived for it, one of them must not strand the rest of the chat, and the closing `verify` still lists it as outstanding. A re-read that fails for any other reason is counted as a failed download, not a skip, because that is what it is — the connection that serves the re-read is the one that serves the file. So it is retried with the rest, it shows up in the progress report and the closing failure list, and enough of them in a row trip the same breaker below. **Failures.** A failed download is retried inside the run: up to three passes over whatever is still missing, spaced a minute and then two apart. The failure this exists for is the transient one — a connection that dies takes every transfer in flight with it, and all of them are fetchable again minutes later — and leaving them to the next run costs a full re-walk of the chat and a re-index of the remote before a byte can move. Each failure is reported with the reason Telegram gave for it, not just the byte count that arrived. Either leg gives up once five transfers in a row fail. A source or destination that is refusing everything will refuse the rest of the list too, in milliseconds, so the run stops and exits 3 instead of spending the whole outstanding list finding that out. A run that trips and then recovers on a retry reports nothing. ## Replacing the shell pipeline Earlier versions of this repo were three bash scripts — `run.sh`, `export-until-complete.sh` and `verify-export.sh` — driving `tdl` and `rclone` as separate processes. Everything expensive in them existed to work around the fact that neither process could see the other's state: a staging directory polled with `du -sk`, an `--min-age` guard, a `*.tmp` exclusion, `SIGSTOP`/`SIGCONT` to enforce the disk cap, a sweep-failure counter, and an outer loop that re-verified and re-narrowed a JSON export between passes. One process needs none of it. Completion is a function returning; the cap is a semaphore. Some hard-won details were worth keeping, and are: - **pikpak commits uploads as a server-side async task**, and rclone abandons a still-pending one when its low-level retries run out. `transfers=2` and `low-level-retries=20` are the defaults here for that reason. Environment overrides still win. - **A backend with no quota API is treated as unlimited**, so it never blocks a run. - **Zero-byte files count as missing** — rclone overwrites a size-mismatched destination, so re-running repairs them — while files under 1 KiB are reported but trusted, since some real media genuinely is that small. - **Indexing ignores `RCLONE_*` filters.** The transfer tunables above are deliberately env-overridable; the listing is not. A stray `RCLONE_EXCLUDE` or `RCLONE_MIN_SIZE` left over from another job would otherwise narrow the index and re-download everything it hid. ## Notes - `tgexport` and the `tdl` CLI share one session store and cannot run against the same namespace at once. Use `-n` for a second namespace if you need both. - A partially downloaded file is not resumable across restarts — tdl's library exposes no resume offset — so an interrupted run re-fetches whatever was in flight, bounded by `--limit`. - Everything is read-only against Telegram. Nothing is uploaded, deleted, or marked read.