This might help you

@app.route('/createInvoice', methods=['POST'])
def createInvoice():
    try:
        models = xmlrpc.client.ServerProxy('{}/xmlrpc/2/object'.format(url))
        data = request.get_json()
        if not data:
            return jsonify({'message': 'No data received.'}), 400
        
        sale_order_id = int(data.get('sale_order_id'))
        product_id = int(data.get('product_variant_id'))
        
        if not sale_order_id or not product_id:
            return jsonify({'message': 'Invalid input data.'}), 400
        
        # Fetch data related to the sale order
        sale_order_data = models.execute_kw(db, uid, password, 'sale.order', 'read', 
                                            [sale_order_id], 
                                            {'fields': ['partner_id', 'invoice_status', 'name', 'order_line', 'picking_ids']})
        
        if not sale_order_data:
            return jsonify({'message': 'Sale order not found.'}), 404
        
        invoice_id = None
        
        # Iterate through each picking related to the sale order
        for picking_line in sale_order_data[0].get('picking_ids', []):
            picking_line_data = models.execute_kw(db, uid, password, 'stock.picking', 'search_read', 
                                                [[['id', '=', int(picking_line)],['product_id','=', int(product_id)]]], {})
            # If picking data is found
            if picking_line_data:
                stock_picking_validate = models.execute_kw(db, uid, password, 'stock.picking', 'button_validate', [[picking_line]])
        
        # Iterate through each line of the sale order
        for lineId in sale_order_data[0].get('order_line', []):
            sale_order_line = models.execute_kw(db, uid, password, 'sale.order.line', 'search_read', 
                                                [[["id", "=", lineId],['product_id','=', product_id]]], {})
            if sale_order_line:
                # Generate invoice for the sale order line
                current_date = datetime.now().strftime('%Y-%m-%d')
                context = {
                    'move_type': 'out_invoice',
                    'partner_id': sale_order_data[0]['partner_id'][0],
                    'invoice_origin': sale_order_data[0]['name'],
                    'invoice_date': current_date,
                    'partner_bank_id': 164, #Keep your bank ID
                    'l10n_in_gst_treatment': 'consumer', #Keep your GST treatment (Consumer or Supplier)
                    'ref': '',
                    'l10n_in_type_id': 1, #Eway Bill Document type - ID
                    'l10n_in_mode': '1', #Mode Of Transport - ID
                    'l10n_in_distance': 11, #Distance travelled by vehicle
                    'l10n_in_vehicle_type': 'R', #Vehicle Type - Char
                    'l10n_in_vehicle_no': 'AP00AA0000' #Vehicle Number - Char
                }
                # Create invoice in the system
                invoice_id = models.execute_kw(db, uid, password, 'account.move', 'create', [context])
                invoice_lines = []
                # Populate invoice lines
                for lineId in sale_order_data[0].get('order_line', []):
                    sale_order_line = models.execute_kw(db, uid, password, 'sale.order.line', 'read', [lineId], {})
                    invoice_lines.append((0, 0, {
                        'move_id': int(invoice_id),
                        'product_id': int(sale_order_line[0]['product_id'][0]),
                        'quantity': float(sale_order_line[0]['product_uom_qty']),
                        'price_unit': float(sale_order_line[0]['price_unit']),
                        'name': sale_order_line[0]['name']
                    }))
                # Write invoice lines to the invoice
                models.execute_kw(db, uid, password, 'account.move', 'write', [invoice_id, {'invoice_line_ids': invoice_lines}])
                # Post the invoice
                models.execute_kw(db, uid, password, 'account.move', 'action_post', [invoice_id])
                # Find the invoice line ID
                inv_line_id = models.execute_kw(db, uid, password, 'account.move.line', 'search', 
                                                 [[['product_id', '=', sale_order_line[0]['product_id'][0]], 
                                                   ['move_id', '=', invoice_id], 
                                                   ['quantity', '=', sale_order_line[0]['product_uom_qty']]]])
                # Update sale order line with invoice line and invoice status
                models.execute_kw(db, uid, password, 'sale.order.line', 'write', 
                                  [lineId, {'invoice_lines': [(4, inv_line_id[0])], 'invoice_status': 'invoiced'}])
                # Update sale order with invoice ID and invoice status
                models.execute_kw(db, uid, password, 'sale.order', 'write', 
                                  [[sale_order_id], {'invoice_ids': [(4, invoice_id)], 'invoice_status': 'invoiced'}])
                # Return response based on whether invoice was created or not
                if invoice_id:
                    return jsonify({'invoice_id': invoice_id, 'message':'Invoice created successfully.'}), 200
                else:
                    return jsonify({'message': 'No invoice created for the given conditions.'}), 200
        
        # If no invoice was created
        return jsonify({'message': 'No invoice created.'}), 404
        
    except Exception as e:
        print(f"An error occurred: {e}")
        return jsonify({'message': 'An error occurred while processing the request.'}), 500

Hi Ahmad,

invoice_id = 279777

sale_id = 16

sale_id = models.execute_kw(db, uid, password, 'sale.order', 'search_read', [[

['id', '=', 16]]], {'fields': ['order_line']})

for line in sale_id[0]['order_line']:

sale_line_id = models.execute_kw(db, uid, password, 'sale.order.line', 'search_read', [[

['id', '=', line]]], {'fields': ['product_template_id', 'product_uom_qty']})

product_id = models.execute_kw(db, uid, password, 'product.product', 'search', [[

['product_tmpl_id', '=', sale_line_id[0]['product_template_id'][0]]]])

inv_line_id = models.execute_kw(db, uid, password, 'account.move.line', 'search', [[

['product_id', '=', product_id[0]], 

['move_id', '=', 279777], 

['quantity', '=', sale_line_id[0]['product_uom_qty']]]])

if inv_line_id:

models.execute_kw(db, uid, password, 'sale.order.line', 'write', [line,

{'invoice_lines':[(4, inv_line_id[0])]}])

Regards,

Email:      odoo@aktivsoftware.com  

Skype: kalpeshmaheshwari