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TelegramDL

Features & Download Engine

TelegramDL is specifically engineered to maximize speed, reliability, and flexibility when downloading media from Telegram.

Section titled “Supported Link Formats”

TelegramDL features an intelligent URL parser (pkg/downloader/parser.go) that handles direct messages, continuous ranges, and forum topics:

Link Format Type Description
https://t.me/c/2121902112/31449 Single private channel message Downloads media from message 31449
https://t.me/c/2121902112/31449-31455 Message Range Queues all messages from 31449 to 31455
https://t.me/publicchannel/1234 Public channel or supergroup Downloads message 1234 from public channel
https://t.me/c/2121902112/450/455 Topic message Downloads message 455 within topic 450

Multi-Worker Chunk Download Engine

Section titled “Multi-Worker Chunk Download Engine”

The download engine (pkg/downloader/engine.go) performs parallel segmented downloads directly over the MTProto protocol:

graph TD
    A[File in Telegram DC] --> B[512 KB Chunk Slicer]
    B --> W1[Worker 1]
    B --> W2[Worker 2]
    B --> W3[Worker 3]
    B --> W4[Worker 4...8]
    W1 --> D[Concurrent File.WriteAt]
    W2 --> D
    W3 --> D
    W4 --> D
    D --> E[Verified Output File]

Engine Highlights:

Section titled “Engine Highlights:”
  1. Per-file Concurrency: Assigns up to 8 parallel workers per download, saturating your available network bandwidth.
  2. Global Concurrency Semaphore: Throttles active tasks (MaxConcurrentDownloads, default 3 active tasks) to avoid rate limits.
  3. Deduplication Safeguards: If a file already exists on disk with identical size, it is immediately marked as skipped (100% complete) without network transfer.
  4. Smoothed Speed Calculation: Uses exponential moving averages to prevent misleading bandwidth spikes.

Intelligent Chunk-based Resume

Section titled “Intelligent Chunk-based Resume”

Unlike sequential download tools:

  • Finished chunks are recorded in SQLite’s download_chunks table.
  • Active files are saved with a temporary .temp suffix.
  • If network drops, your PC reboots, or a task is paused, already downloaded chunks are never re-transferred.
  • Upon reaching 100% completion, the .temp file is seamlessly renamed to its final filename.

Complete Task Management

Section titled “Complete Task Management”

From either the UI or the REST API, you can control any task at any time:

  • Pause: Stops network transfer and frees up workers for queued tasks.
  • Resume: Re-enqueues the task, continuing from the last downloaded chunk.
  • Cancel: Aborts active network context and marks the item as cancelled.
  • Retry: Re-queues any failed or cancelled downloads.
  • Delete: Removes database records and optionally purges the file from disk.
  • Clear History: Purges completed, failed, or cancelled records while preserving downloaded files.

Speed Throttling

Section titled “Speed Throttling”

You can set a global speed limit (in KB/s or MB/s) from the status bar or the Settings view. The engine adjusts chunk dispatching dynamically to prevent network congestion.

Automatic Shutdown When the Queue Finishes

Section titled “Automatic Shutdown When the Queue Finishes”

The «Apagar al terminar» (Power off when done) switch in the sidebar (between Settings and your user) arms PC shutdown:

  • Once the download queue becomes empty after having activity, the server waits a 15-second grace period and powers off the machine.
  • Queueing any download during the countdown cancels the shutdown automatically; turning the switch off or closing the application cancels it too.
  • While a shutdown is scheduled, the sidebar shows a live countdown.
  • The setting is not persisted: it is session-only, so every time you open the application it starts off and must be armed again. This avoids an unexpected shutdown one day just because it was left on in another session.

On Windows it shuts down via shutdown /s /t 0 without forcing applications to close: a program with unsaved work may hold the shutdown.