Sending Documents via Telegram Bot

1. Create Document Bot

# Create bot for document automation
1. Message @BotFather in Telegram
2. Send: /newbot
3. Bot name: "Document Delivery Bot"
4. Username: "your_document_bot"
5. Save token: 123456789:ABC-DEF1234ghIkl-zyx57W2v1u123ew11

# Essential bot commands for document handling
/setcommands to @BotFather

send_pdf - Send PDF document
send_doc - Send Office document  
send_file - Send any file type
list_files - View available documents
help - Get usage instructions

2. API Endpoint Configuration

POST https://api.telegram.org/bot<TOKEN>/sendDocument

Required Parameters:
- chat_id: Target chat or user ID
- document: File to send (multipart/form-data or file_id)

Optional Parameters:  
- caption: Document description (up to 1024 characters)
- parse_mode: HTML or Markdown formatting
- reply_to_message_id: Reply to specific message
- disable_notification: Silent sending

Batch Document Sending

// Advanced batch processing with rate limiting
class DocumentBatchSender {
  constructor(botToken) {
    this.botToken = botToken;
    this.queue = [];
    this.processing = false;
    this.rateLimitDelay = 1000; // 1 second between requests
  }
  
  addToQueue(chatId, filePath, caption) {
    this.queue.push({ chatId, filePath, caption });
    if (!this.processing) this.processQueue();
  }
  
  async processQueue() {
    this.processing = true;
    
    while (this.queue.length > 0) {
      const { chatId, filePath, caption } = this.queue.shift();
      
      try {
        await this.sendDocument(chatId, filePath, caption);
        console.log(`✅ Sent: ${filePath} to ${chatId}`);
      } catch (error) {
        console.error(`❌ Failed: ${filePath}`, error);
        // Implement retry logic here
      }
      
      // Rate limiting delay
      await new Promise(resolve => setTimeout(resolve, this.rateLimitDelay));
    }
    
    this.processing = false;
  }
}

File ID Caching Strategy

// Efficient file caching system
class TelegramFileCache {
  constructor() {
    this.cache = new Map(); // In production, use Redis/Database
  }
  
  async sendCachedDocument(chatId, filePath, caption) {
    const cacheKey = `file:${filePath}`;
    let fileId = this.cache.get(cacheKey);
    
    if (!fileId) {
      // First time upload - store file_id for future use
      const result = await this.uploadDocument(chatId, filePath, caption);
      fileId = result.document.file_id;
      this.cache.set(cacheKey, fileId);
      return result;
    } else {
      // Use cached file_id for instant delivery
      return this.sendByFileId(chatId, fileId, caption);
    }
  }
  
  async sendByFileId(chatId, fileId, caption) {
    const response = await fetch(`https://api.telegram.org/bot${BOT_TOKEN}/sendDocument`, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        chat_id: chatId,
        document: fileId,
        caption: caption
      })
    });
    
    return response.json();
  }
}

Dynamic Document Generation & Sending

const PDFDocument = require('pdfkit');
const fs = require('fs');

async function generateAndSendReport(chatId, data) {
  const filename = `report_${Date.now()}.pdf`;
  const doc = new PDFDocument();
  
  // Generate PDF with dynamic data
  doc.pipe(fs.createWriteStream(filename));
  doc.fontSize(20).text('Sales Report', 100, 100);
  doc.fontSize(12).text(`Generated: ${new Date().toLocaleDateString()}`, 100, 130);
  
  // Add data tables, charts, etc.
  data.forEach((item, index) => {
    doc.text(`${item.name}: ${item.value}`, 100, 160 + (index * 20));
  });
  
  doc.end();
  
  // Wait for PDF generation to complete
  return new Promise((resolve) => {
    doc.on('end', async () => {
      // Send generated document
      const result = await sendDocument(
        chatId, 
        filename, 
        `📊 <b>Automated Report</b>\n🕐 Generated: ${new Date().toLocaleString()}`
      );
      
      // Clean up temporary file
      fs.unlinkSync(filename);
      resolve(result);
    });
  });
}