Telegram Convert File

Description

This module downloads files (images, documents, etc.) received through a Telegram bot using the file_id provided by the Telegram API. Its execution flow is:

1. Gets the file_id from the input content (data.content).
2. Verifies that the botToken is available in the input data.
3. Calls the Telegram getFile API to get the file path on Telegram servers.
4. Downloads the file from https://api.telegram.org/file/bot{token}/{file_path}.
5. Saves the file to the temporary directory temporal/cli_{client_id}/:
   • For photos: generates a name with timestamp (image-{timestamp}.png).
   • For documents: uses the original file name (data.metadata.file_name).
6. Generates a public download URL based on ENGINE_HOST.
7. Returns the original data enriched with filename, filePath (local path) and urlPath (public URL).

The downloaded file is available for subsequent nodes that need to process it (e.g.: agentChat for image analysis, sendMail for attachments, etc.).

Configuration

This module has no configuration parameters in scheme. The necessary data is obtained from the flow input:

Parameter (in input data)	Type	Required	Description
content	text	Yes	The file_id of the file sent by Telegram (e.g.: message.photo[n].file_id).
botToken	text	Yes	Telegram bot token.
chatId	text	No	Telegram chat ID.
type	text	No	File type: “photo” for images, other for documents.
metadata.file_name	text	No	Original file name (for documents).

Credentials

The Telegram bot botToken is expected in data.botToken. It does not use the credentials system directly but receives the token from the Telegram trigger node.

Output

{
  "nextModule": "siguiente-nodo",
  "data": {
    "content": "AgACAgIAAxkBAAI...",
    "botToken": "123456:ABC-DEF...",
    "chatId": "987654321",
    "type": "photo",
    "filename": "image-1711180800000.png",
    "filePath": "/app/temporal/cli_1/image-1711180800000.png",
    "urlPath": "https://mi-engine.com/download/cli_1/image-1711180800000.png"
  }
}

Usage Example

Basic case

This module is placed after a Telegram trigger that receives messages with files. Typical input data comes automatically from the trigger:

{
  "content": "AgACAgIAAxkBAAI...",
  "botToken": "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11",
  "chatId": "987654321",
  "type": "photo",
  "metadata": {
    "file_name": "documento.pdf"
  }
}

API Used

• Telegram Bot API:
  • GET https://api.telegram.org/bot{token}/getFile?file_id={fileId} - Get file path.
  • GET https://api.telegram.org/file/bot{token}/{file_path} - Download the file.
• Documentation: https://core.telegram.org/bots/api#getfile

Notes

• Files are saved in temporal/cli_{client_id}/. The directory is created automatically if it doesn’t exist.
• Telegram has a 20 MB limit for file downloads via the bots API.
• For photos, the name is automatically generated with a timestamp. For documents, the original name is used.
• The public download URL depends on the ENGINE_HOST environment variable.
• The original input data is preserved in the output, enriched with the file fields.
• This module is ideal for preprocessing files before passing them to modules like agentChat (image analysis) or sendMail (attachments).

Related Nodes

• agentChat (Conversational AI Agent - for analyzing downloaded images)
• sendMail (Send Mail - for attaching downloaded files)
• openaiImages (OpenAI Generate Image)