This is a serverless Telegram bot that transcribes voice, audio, and video notes sent to it using the Groq Whisper API. It also stores and retrieves transcriptions using AWS DynamoDB.

1. The bot receives a voice, audio, or video note message from a user.
2. It downloads the file from Telegram and checks its duration. If the duration is above a specified limit, it sends a warning message to the user and exits.
3. The bot checks if the transcription already exists in AWS DynamoDB. If it does, the saved transcription is sent back to the user.
4. If no transcription is found, the bot uploads the original media to the Groq Whisper API for transcription.
5. The transcription is sent back to the user as a text message and stored in DynamoDB for future reference.

• /start: Initializes the bot and provides a welcome message
• /help: Provides information on how to use the bot and its features
• /transcribe: Transcribes the voice, audio, or video note in the reply message
• /translate: Translates (into English) the voice, audio, or video note in the reply message
• /summarize: Summarizes the voice, audio, or video note in the reply message
• /caveman: Transcribes the voice, audio, or video note in the reply message in a "caveman" style

Developer commands have been removed.

• The bot is built using the teloxide crate for interacting with the Telegram API.
• The transcription is done using the reqwest crate to send a request to the Groq Whisper API.
• The original file from Telegram is uploaded directly to the Groq Whisper API. FFmpeg has been removed due to memory constraints in the serverless environment, so no conversion step is performed.
• The bot uses AWS DynamoDB to cache transcriptions and translations, lowering the amount of API calls. The cache is cleared after 7 days.
• The bot is deployed as a serverless function using AWS Lambda.

• Robust Error Handling: All errors are properly handled and return HTTP 200 to prevent Telegram webhook retry loops.
• Secret Token Validation: Validates webhook requests using the X-Telegram-Bot-Api-Secret-Token header. This is more reliable than IP checking and works correctly behind proxies. Unauthorized requests are silently rejected.
• Multi-API-Key Support: Configure multiple Groq API keys for automatic failover. When a rate limit is hit, the bot automatically tries the next key.
• Rate Limit Feedback: When all API keys are rate limited, the bot reacts with a 😴 emoji on the message to provide visual feedback without spamming the user.
• Type-Safe Errors: Uses a custom TranscriptionError enum for clean error categorization (rate limits, network errors, parse errors, API errors).

• TELEGRAM_BOT_TOKEN: the token for the Telegram bot.
• TELEGRAM_SECRET_TOKEN: a secret token for validating webhook requests. You can use any random string (e.g., generate one with openssl rand -hex 32). This token must be provided when setting up the webhook.
• GROQ_API_KEY: the API key(s) for the Groq Whisper API. Supports multiple keys separated by commas for automatic failover on rate limits (e.g., key1,key2,key3).
• DYNAMODB_TABLE: the name of the DynamoDB table where transcriptions are stored.

Before deploying this bot, ensure you have the following prerequisites installed:

• AWS CLI: Follow the instructions here to install the AWS Command Line Interface.
• cargo-lambda: Install cargo-lambda (not with cargo, it doesn't support cross compilation) by following the instructions here.

To build:

cargo lambda build --release --arm64

To deploy:

cargo lambda deploy

After deploying your Lambda function, you need to configure the Telegram webhook to point to your Lambda function URL.

Replace <YOUR_BOT_TOKEN> with your Telegram bot token, <YOUR_LAMBDA_URL> with your Lambda function URL, and <YOUR_SECRET_TOKEN> with the secret token you set in the TELEGRAM_SECRET_TOKEN environment variable:

curl -X POST "https://api.telegram.org/bot<YOUR_BOT_TOKEN>/setWebhook" \ -H "Content-Type: application/json" \ -d '{  "url": "<YOUR_LAMBDA_URL>",  "secret_token": "<YOUR_SECRET_TOKEN>",  "allowed_updates": ["message"]  }'

Important:

• The secret_token parameter must match the TELEGRAM_SECRET_TOKEN environment variable you configured in your Lambda function. This validates that webhook requests are coming from Telegram.
• The allowed_updates parameter can be set to ["message"] to ensure the bot only receives message updates and nothing else (like inline queries, polls, etc.). This will reduce Lambda costs.

If the bot is stuck in a loop or something goes wrong, you can reset the webhook and drop all pending updates:

curl -X POST "https://api.telegram.org/bot<YOUR_BOT_TOKEN>/setWebhook" \ -H "Content-Type: application/json" \ -d '{  "url": "<YOUR_LAMBDA_URL>",  "secret_token": "<YOUR_SECRET_TOKEN>",  "allowed_updates": ["message"],  "drop_pending_updates": true  }'

FFmpeg has been removed due to memory constraints in the serverless environment and is no longer required.

Ensure that your AWS Lambda function has the necessary permissions to access DynamoDB. You will need to attach a policy that grants the Lambda function read and write permissions to the DynamoDB table. This can be done by attaching the AWSLambdaDynamoDBExecutionRole managed policy or by creating a custom policy with the necessary permissions.

This project is licensed under the GNU General Public License v3.0. See the LICENSE file for details.

Contributions are welcome! If you'd like to help improve this bot, please open a pull request with your changes.