feat(pos): add real thermal ticket printing via ESC/POS (#21)
- Add thermal_printer.py service generating raw ESC/POS bytes for 58mm/80mm printers - Add /pos/api/sales/<id>/print endpoint (escpos_raw or browser mode) - Add printer.js with WebUSB and Web Serial support for direct browser-to-printer - Add thermal print button in ticket modal with connect/print workflow Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
@@ -1698,3 +1698,96 @@ def push_test():
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if ok:
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return jsonify({'message': 'Test notification sent'})
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return jsonify({'error': 'No subscription found or push failed'}), 400
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# ─── Thermal Printing ──────────────────────────────
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@pos_bp.route('/sales/<int:sale_id>/print', methods=['POST'])
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@require_auth('pos.sell')
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def print_ticket(sale_id):
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"""Generate a printable ticket for a sale.
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Body (optional): {printer_type: 'escpos_raw' | 'browser', width: 58 | 80}
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- escpos_raw: returns raw ESC/POS bytes (application/octet-stream)
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- browser: returns printable HTML fragment (text/html)
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"""
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from flask import Response
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from services.thermal_printer import generate_ticket
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body = request.get_json(silent=True) or {}
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printer_type = body.get('printer_type', 'escpos_raw')
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width = int(body.get('width', 80))
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conn = get_tenant_conn(g.tenant_id)
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cur = conn.cursor()
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# Fetch sale
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cur.execute("""
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SELECT s.*, e.name as employee_name, c.name as customer_name
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FROM sales s
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LEFT JOIN employees e ON s.employee_id = e.id
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LEFT JOIN customers c ON s.customer_id = c.id
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WHERE s.id = %s
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""", (sale_id,))
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row = cur.fetchone()
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if not row:
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cur.close(); conn.close()
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return jsonify({'error': 'Sale not found'}), 404
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cols = [desc[0] for desc in cur.description]
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sale = dict(zip(cols, row))
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for k in ('subtotal', 'discount_total', 'tax_total', 'total', 'amount_paid', 'change_given'):
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if sale.get(k) is not None:
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sale[k] = float(sale[k])
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# Fetch items
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cur.execute("""
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SELECT name, quantity, unit_price, subtotal
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FROM sale_items WHERE sale_id = %s ORDER BY id
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""", (sale_id,))
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items = []
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for r in cur.fetchall():
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items.append({
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'name': r[0], 'quantity': r[1],
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'unit_price': float(r[2]) if r[2] else 0,
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'subtotal': float(r[3]) if r[3] else 0,
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})
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# Fetch business info from config
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business_info = {'name': 'NEXUS AUTOPARTS', 'rfc': '', 'address': ''}
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try:
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cur.execute("SELECT key, value FROM config WHERE key IN ('business_name','rfc','address')")
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for rw in cur.fetchall():
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if rw[0] == 'business_name':
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business_info['name'] = rw[1]
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else:
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business_info[rw[0]] = rw[1]
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except Exception:
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pass
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cur.close()
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conn.close()
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sale_data = {
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'folio': f'V-{sale["id"]}',
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'date': str(sale.get('created_at', '')),
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'employee': sale.get('employee_name', ''),
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'customer': sale.get('customer_name', ''),
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'items': items,
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'subtotal': sale.get('subtotal', 0),
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'discount_total': sale.get('discount_total', 0),
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'tax_total': sale.get('tax_total', 0),
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'total': sale.get('total', 0),
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'payment_method': sale.get('payment_method', 'efectivo'),
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'amount_paid': sale.get('amount_paid'),
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'change_given': sale.get('change_given'),
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}
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if printer_type == 'browser':
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# Return the sale data as JSON for browser-side rendering
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return jsonify(sale_data)
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# Default: ESC/POS raw bytes
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raw = generate_ticket(sale_data, business_info, width=width)
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return Response(raw, mimetype='application/octet-stream',
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headers={'Content-Disposition': f'attachment; filename=ticket_{sale_id}.bin'})
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119
pos/services/thermal_printer.py
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119
pos/services/thermal_printer.py
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@@ -0,0 +1,119 @@
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"""ESC/POS thermal printer commands for 58mm and 80mm printers.
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Generates raw ESC/POS byte commands that can be sent to a thermal printer
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via USB, serial, or network connection.
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"""
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# ESC/POS command constants
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ESC = b'\x1b'
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GS = b'\x1d'
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INIT = ESC + b'@' # Initialize printer
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CUT = GS + b'V' + b'\x00' # Full cut
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PARTIAL_CUT = GS + b'V' + b'\x01'
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FEED = ESC + b'd' # Feed N lines
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ALIGN_LEFT = ESC + b'a' + b'\x00'
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ALIGN_CENTER = ESC + b'a' + b'\x01'
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ALIGN_RIGHT = ESC + b'a' + b'\x02'
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BOLD_ON = ESC + b'E' + b'\x01'
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BOLD_OFF = ESC + b'E' + b'\x00'
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DOUBLE_HEIGHT = ESC + b'!' + b'\x10'
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NORMAL_SIZE = ESC + b'!' + b'\x00'
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LARGE_SIZE = ESC + b'!' + b'\x30' # Double width + double height
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def generate_ticket(sale_data, business_info, width=80):
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"""Generate ESC/POS bytes for a sale ticket.
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Args:
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sale_data: dict with sale info (items, totals, payment, folio)
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business_info: dict with business name, RFC, address
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width: 58 or 80 (mm)
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Returns: bytes ready to send to printer
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"""
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chars = 32 if width == 58 else 48 # characters per line
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buf = bytearray()
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buf += INIT
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# Header: business name (centered, bold, large)
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buf += ALIGN_CENTER
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buf += LARGE_SIZE
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buf += (business_info.get('name', 'NEXUS POS') + '\n').encode('cp437', errors='replace')
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buf += NORMAL_SIZE
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buf += (business_info.get('rfc', '') + '\n').encode('cp437', errors='replace')
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buf += (business_info.get('address', '') + '\n').encode('cp437', errors='replace')
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buf += b'\n'
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# Folio + date
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buf += ALIGN_LEFT
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buf += BOLD_ON
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folio = sale_data.get('folio', 'N/A')
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date = sale_data.get('date', '')
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buf += f'Folio: {folio}\n'.encode('cp437', errors='replace')
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buf += BOLD_OFF
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buf += f'Fecha: {date}\n'.encode('cp437', errors='replace')
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buf += f'Cajero: {sale_data.get("employee", "")}\n'.encode('cp437', errors='replace')
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if sale_data.get('customer'):
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buf += f'Cliente: {sale_data["customer"]}\n'.encode('cp437', errors='replace')
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buf += ('-' * chars + '\n').encode()
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# Column header
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buf += BOLD_ON
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hdr = _format_line('Cant Descripcion', 'Importe', chars)
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buf += (hdr + '\n').encode('cp437', errors='replace')
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buf += BOLD_OFF
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buf += ('-' * chars + '\n').encode()
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# Items
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for item in sale_data.get('items', []):
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name = item.get('name', '')[:chars - 10]
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qty = item.get('quantity', 1)
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subtotal = item.get('subtotal', 0)
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buf += f'{qty}x {name}\n'.encode('cp437', errors='replace')
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buf += ALIGN_RIGHT
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buf += f'${subtotal:,.2f}\n'.encode('cp437', errors='replace')
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buf += ALIGN_LEFT
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buf += ('-' * chars + '\n').encode()
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# Totals
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buf += ALIGN_RIGHT
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buf += _total_line('Subtotal:', sale_data.get('subtotal', 0), chars).encode('cp437', errors='replace')
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if sale_data.get('discount_total', 0) > 0:
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buf += _total_line('Descuento:', -sale_data['discount_total'], chars).encode('cp437', errors='replace')
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buf += _total_line('IVA 16%:', sale_data.get('tax_total', 0), chars).encode('cp437', errors='replace')
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buf += BOLD_ON + DOUBLE_HEIGHT
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buf += _total_line('TOTAL:', sale_data.get('total', 0), chars).encode('cp437', errors='replace')
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buf += NORMAL_SIZE + BOLD_OFF
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# Payment
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buf += ALIGN_LEFT
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buf += f'\nPago: {sale_data.get("payment_method", "Efectivo")}\n'.encode('cp437', errors='replace')
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if sale_data.get('amount_paid'):
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buf += f'Recibido: ${sale_data["amount_paid"]:,.2f}\n'.encode('cp437', errors='replace')
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if sale_data.get('change_given'):
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buf += f'Cambio: ${sale_data["change_given"]:,.2f}\n'.encode('cp437', errors='replace')
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# Footer
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buf += b'\n'
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buf += ALIGN_CENTER
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buf += 'Gracias por su compra!\n'.encode('cp437', errors='replace')
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buf += 'Nexus Autoparts POS\n'.encode('cp437', errors='replace')
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buf += b'\n\n\n'
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buf += PARTIAL_CUT
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return bytes(buf)
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def _format_line(left, right, width):
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"""Pad a left-right line to fill the ticket width."""
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space = width - len(left) - len(right)
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if space < 1:
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space = 1
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return left + ' ' * space + right
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def _total_line(label, amount, width):
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"""Format a totals line like 'Subtotal: $1,234.56'."""
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val = f'${abs(amount):,.2f}' if amount >= 0 else f'-${abs(amount):,.2f}'
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return _format_line(label, val, width) + '\n'
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@@ -26,7 +26,11 @@ const POS = (() => {
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let searchTimeout = null;
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let customerSearchTimeout = null;
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const fmt = (n) => '$' + parseFloat(n || 0).toLocaleString('es-MX', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
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// Currency-aware formatter: reads pos_currency from localStorage
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const _posCurrency = localStorage.getItem('pos_currency') || 'MXN';
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const _currSymbols = { MXN: '$', USD: 'US$' };
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const _currLocale = _posCurrency === 'USD' ? 'en-US' : 'es-MX';
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const fmt = (n) => (_currSymbols[_posCurrency] || '$') + parseFloat(n || 0).toLocaleString(_currLocale, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
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function headers() {
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return { 'Content-Type': 'application/json', 'Authorization': 'Bearer ' + token };
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@@ -940,6 +944,45 @@ const POS = (() => {
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setTimeout(() => { if (area) area.style.display = 'none'; }, 500);
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}
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// ─── Thermal Printing ─────────────────
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async function connectThermal() {
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if (!window.NexusPrinter) { showToast('Printer module not loaded'); return; }
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const result = await NexusPrinter.connect();
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if (result.ok) {
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showToast('Impresora conectada: ' + (result.name || result.type));
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_updatePrinterButtons();
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} else {
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showToast(result.error || 'No se pudo conectar la impresora');
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}
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}
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async function thermalPrint() {
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if (!window.NexusPrinter || !NexusPrinter.isConnected()) {
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showToast('Conecte una impresora termica primero');
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return;
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}
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if (!lastSaleId) { showToast('No hay venta para imprimir'); return; }
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const ok = await NexusPrinter.printSale(lastSaleId);
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if (ok) {
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showToast('Ticket enviado a impresora termica');
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} else {
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showToast('Error al imprimir. Reconecte la impresora.');
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}
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}
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function _updatePrinterButtons() {
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const connectBtn = document.getElementById('btnConnectPrinter');
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const thermalBtn = document.getElementById('btnThermalPrint');
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if (window.NexusPrinter && NexusPrinter.isConnected()) {
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if (connectBtn) connectBtn.style.display = 'none';
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if (thermalBtn) thermalBtn.style.display = '';
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} else {
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if (connectBtn) connectBtn.style.display = '';
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if (thermalBtn) thermalBtn.style.display = 'none';
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}
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}
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// ─── Last Sale ───────────────────────
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async function showLastSale() {
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if (!lastSaleId) { showToast('No hay venta reciente'); return; }
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@@ -1078,5 +1121,6 @@ const POS = (() => {
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creditSale, saveQuotation, createLayaway,
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showLastSale, openDrawer,
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showTicket, closeTicketModal, printTicket,
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connectThermal, thermalPrint,
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};
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})();
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152
pos/static/js/printer.js
Normal file
152
pos/static/js/printer.js
Normal file
@@ -0,0 +1,152 @@
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/**
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* NexusPrinter — Web USB / Web Serial bridge for thermal printers.
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*
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* Connects to 58mm or 80mm ESC/POS printers via WebUSB or Web Serial APIs
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* and sends raw byte commands generated by the backend.
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*/
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window.NexusPrinter = (function () {
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'use strict';
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let _device = null; // WebUSB device
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let _endpoint = null; // USB bulk-out endpoint number
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let _serialPort = null; // Web Serial port
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let _writer = null; // Serial writable stream writer
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let _type = null; // 'usb' | 'serial' | null
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// ── Connection ─────────────────────────────────
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async function connect() {
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// Try WebUSB first
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if ('usb' in navigator) {
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try {
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_device = await navigator.usb.requestDevice({ filters: [] });
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await _device.open();
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// Select first configuration if needed
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if (_device.configuration === null) {
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await _device.selectConfiguration(1);
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}
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// Claim first interface and find bulk-out endpoint
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const iface = _device.configuration.interfaces[0];
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await _device.claimInterface(iface.interfaceNumber);
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const alt = iface.alternates[0];
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const ep = alt.endpoints.find(e => e.direction === 'out' && e.type === 'bulk');
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if (ep) {
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_endpoint = ep.endpointNumber;
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_type = 'usb';
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_save();
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return { ok: true, type: 'usb', name: _device.productName || 'USB Printer' };
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}
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} catch (e) {
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// User cancelled or no USB device available
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_device = null;
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}
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}
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// Fall back to Web Serial
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if ('serial' in navigator) {
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try {
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_serialPort = await navigator.serial.requestPort();
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await _serialPort.open({ baudRate: 9600 });
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_writer = _serialPort.writable.getWriter();
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_type = 'serial';
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_save();
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return { ok: true, type: 'serial', name: 'Serial Printer' };
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} catch (e) {
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_serialPort = null;
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_writer = null;
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}
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}
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return { ok: false, error: 'No printer connected. Use a browser that supports WebUSB or Web Serial (Chrome/Edge).' };
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}
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async function disconnect() {
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try {
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if (_type === 'usb' && _device) {
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await _device.close();
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}
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if (_type === 'serial') {
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if (_writer) { _writer.releaseLock(); _writer = null; }
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if (_serialPort) { await _serialPort.close(); _serialPort = null; }
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}
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} catch (e) { /* ignore */ }
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_device = null;
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_endpoint = null;
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_type = null;
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localStorage.removeItem('nexus_printer');
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}
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function isConnected() {
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return _type !== null;
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}
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// ── Printing ───────────────────────────────────
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async function sendRaw(bytes) {
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if (!_type) return false;
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try {
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if (_type === 'usb' && _device && _endpoint !== null) {
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// Send in chunks of 512 bytes (common USB max packet size)
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const chunk = 512;
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for (let i = 0; i < bytes.length; i += chunk) {
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await _device.transferOut(_endpoint, bytes.slice(i, i + chunk));
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}
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return true;
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}
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if (_type === 'serial' && _writer) {
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await _writer.write(bytes);
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return true;
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}
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} catch (e) {
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console.error('[NexusPrinter] send error:', e);
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// Connection likely lost
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await disconnect();
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}
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return false;
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}
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/**
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* Print a sale ticket by fetching ESC/POS bytes from the backend.
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* @param {number} saleId
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* @param {number} [width=80] — 58 or 80 mm
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* @returns {Promise<boolean>}
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*/
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async function printSale(saleId, width) {
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width = width || 80;
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const token = localStorage.getItem('pos_token');
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const resp = await fetch('/pos/api/sales/' + saleId + '/print', {
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method: 'POST',
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headers: {
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'Authorization': 'Bearer ' + token,
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'Content-Type': 'application/json'
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},
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body: JSON.stringify({ printer_type: 'escpos_raw', width: width })
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});
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if (!resp.ok) {
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console.error('[NexusPrinter] backend error', resp.status);
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return false;
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}
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const buf = await resp.arrayBuffer();
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return sendRaw(new Uint8Array(buf));
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}
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// ── Persistence helpers ────────────────────────
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function _save() {
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try { localStorage.setItem('nexus_printer', _type || ''); } catch (e) {}
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}
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// ── Public API ─────────────────────────────────
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return {
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connect: connect,
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disconnect: disconnect,
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isConnected: isConnected,
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sendRaw: sendRaw,
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printSale: printSale
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};
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})();
|
||||
@@ -1380,6 +1380,8 @@
|
||||
</div>
|
||||
<div class="modal-footer">
|
||||
<button class="btn btn-ghost" onclick="POS.closeTicketModal()">Cerrar</button>
|
||||
<button class="btn btn-ghost" id="btnConnectPrinter" onclick="POS.connectThermal()" title="Conectar impresora termica USB/Serial">🖨 Conectar</button>
|
||||
<button class="btn btn-secondary" id="btnThermalPrint" onclick="POS.thermalPrint()" style="display:none;" title="Imprimir en impresora termica">🖨 Termica</button>
|
||||
<button class="btn btn-primary" onclick="POS.printTicket()">Imprimir</button>
|
||||
</div>
|
||||
</div>
|
||||
@@ -1477,8 +1479,10 @@
|
||||
<!-- ================================================================
|
||||
JAVASCRIPT
|
||||
================================================================ -->
|
||||
<script src="/pos/static/js/i18n.js"></script>
|
||||
<script src="/pos/static/js/app-init.js"></script>
|
||||
<script src="/pos/static/js/push.js"></script>
|
||||
<script src="/pos/static/js/printer.js"></script>
|
||||
<script src="/pos/static/js/pos.js"></script>
|
||||
|
||||
<script>
|
||||
|
||||
Reference in New Issue
Block a user