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The Telegram service sends PDF ticket files directly to a configured Telegram chat using the Bot API. It handles multipart form data uploads and provides graceful error handling to never interrupt the user experience.

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Functions

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sendTicketToTelegram

Sends a PDF file to the configured Telegram chat with a formatted caption. 
sendTicketToTelegram(pdfUri: string): Promise<void>
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pdfUri
string
required
Local file URI returned by expo-print (e.g., file:///path/to/ticket.pdf)
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void
void
Returns void. Errors are logged to console but never thrown.

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Example

import { generateTicketPDF } from '@/src/lib/services/pdfService';
import { sendTicketToTelegram } from '@/src/lib/services/telegramService';

// Generate the PDF receipt
const pdfUri = await generateTicketPDF(orderData);

// Send to Telegram (fire and forget)
await sendTicketToTelegram(pdfUri);

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Complete payment flow

import { processMockPayment } from '@/src/lib/core/payments/paymentService';
import { generateTicketPDF } from '@/src/lib/services/pdfService';
import { sendTicketToTelegram } from '@/src/lib/services/telegramService';

const paymentResult = await processMockPayment(totalAmount);

if (paymentResult.success) {
  // Generate PDF
  const ticketUri = await generateTicketPDF({
    items: cartItems,
    subtotal,
    discount,
    total,
    shippingCost,
    serviceType: 'DELIVERY'
  });
  
  // Send to Telegram (non-blocking)
  await sendTicketToTelegram(ticketUri);
  
  // Continue with success flow
  router.push('/payment-success');
}

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Behavior

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Silent failure

The function never throws errors to avoid interrupting the payment success flow. All errors are logged to console: 
try {
  // ... upload logic
} catch (err) {
  console.error('[Telegram] sendTicketToTelegram error:', err);
}

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Missing credentials

If bot credentials are not configured, the function logs a warning and returns early: 
if (!botToken || !chatId) {
  console.warn('[Telegram] Bot credentials not configured. See SETUP2.md.');
  return;
}

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File upload format

The function constructs a FormData object compatible with React Native: 
const formData = new FormData();
formData.append('chat_id', chatId);
formData.append('document', {
  uri: pdfUri,
  name: `ticket_orden_${Date.now()}.pdf`,
  type: 'application/pdf',
} as unknown as Blob);

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Caption format

Each PDF is sent with a Spanish-language caption: 
Ticket de pago — [Restaurant Name]
[Date/Time in es-ES format]
Example: 
Ticket de pago — La Cocina
3/3/2026, 14:32:15

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Configuration

The service requires two environment variables: 
EXPO_PUBLIC_TELEGRAM_BOT_TOKEN=your_bot_token_here
EXPO_PUBLIC_TELEGRAM_CHAT_ID=your_chat_id_here
And uses one config value:
  • Config.restaurant.name - Included in the PDF caption

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Getting credentials

  1. Create a bot: Message @BotFather on Telegram and use /newbot
  2. Get token: BotFather will provide a token like 123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11
  3. Get chat ID:
    • Add your bot to a group or message it directly
    • Visit https://api.telegram.org/bot<TOKEN>/getUpdates
    • Find the chat ID in the response
Refer to SETUP2.md for detailed setup instructions.

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API reference

This service uses the Telegram Bot API: 
POST https://api.telegram.org/bot{TOKEN}/sendDocument
Request format: multipart/form-data Form fields:
  • chat_id (string) - Target chat identifier
  • document (file) - PDF file to send
  • caption (string) - Optional message to accompany the file
Response: JSON object with the sent message details (not parsed by this service)

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Error handling

Possible error scenarios (all handled gracefully):
  • Missing credentials → Warning logged, function returns
  • Network failure → Error logged to console
  • Invalid chat ID → Error logged with API response
  • Bot blocked by user → Error logged with API response
  • File too large → Error logged with API response
Telegram Bot API limits file uploads to 50 MB. Receipt PDFs are typically under 100 KB, so this is rarely an issue.

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Best practices

  1. Never await unnecessarily: Since errors are silent, you can fire-and-forget 
    sendTicketToTelegram(pdfUri); // No await needed
  2. Test credentials early: Check console warnings during development
  3. Monitor delivery: Check your Telegram chat to verify receipts are arriving
  4. Privacy consideration: Ensure the chat ID is for an authorized recipient (business owner, not customers)