From b38dfe2eab942702b8765ef81fc4c6cd391d9e78 Mon Sep 17 00:00:00 2001
From: Gijs Molenaar <gijsmolenaar@gmail.com>
Date: Tue, 13 Oct 2026 19:14:24 +0200
Subject: [PATCH] fix: strip space padding from the structured order code

The S7-1200/1500 order code field is space padded, and only NUL bytes
were stripped, so get_order_code returned "6ES7 212-1BE40-0XB0 " with a
trailing space. The flat S7-300 parser already strips both.
---
 CHANGES.md           |  3 +++
 snap7/szl.py         |  2 +-
 tests/test_server.py | 14 ++++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index b9d296c5..6897013a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -44,6 +44,9 @@ Unreleased
   block (method `0x12`) that real engineering tools send; both previously used the header of a request without data
   and an 8-byte parameter block (#942).
 
+* `get_order_code` no longer keeps the trailing space padding of the order code on S7-1200/1500 CPUs, for example
+  `6ES7 212-1BE40-0XB0 ` is now `6ES7 212-1BE40-0XB0` (#949).
+
 ### Documentation
 
 * Add a "Tested and Verified Hardware" section to the PLC support matrix, listing the CPUs, firmware versions and
diff --git a/snap7/szl.py b/snap7/szl.py
index e540ea61..1d539362 100644
--- a/snap7/szl.py
+++ b/snap7/szl.py
@@ -104,7 +104,7 @@ def _parse_order_code_structured(data: bytes, record_len: int, ndr: int, order_c
 
         if record_id == 0x0001 and record_len >= 22:
             found_structured = True
-            order_code.OrderCode = rec[2:22].rstrip(b"\x00")
+            order_code.OrderCode = rec[2:22].rstrip(b"\x00 ")
             if record_len >= 26 and not has_0x0007 and (rec[23] != 0 or rec[24] != 0):
                 order_code.V1, order_code.V2, order_code.V3 = rec[23], rec[24], rec[25]
 
diff --git a/tests/test_server.py b/tests/test_server.py
index 79e38fbc..ccd8e482 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -857,6 +857,20 @@ def test_parse_order_code_s71516f(self) -> None:
         self.assertEqual(result.V2, 9)
         self.assertEqual(result.V3, 2)
 
+    def test_parse_order_code_strips_trailing_space(self) -> None:
+        """The structured MLFB field is space padded on real PLCs; the padding is not part of the order code."""
+        from snap7.szl import parse_order_code_szl
+        from snap7.type import S7SZL
+
+        payload = b"\x00\x1c\x00\x01\x00\x01" + b"6ES7 212-1BE40-0XB0 " + b"\x00\x00\x00\x02\x00\x00"
+        szl = S7SZL()
+        szl.Header.LengthDR = len(payload)
+        for i, b in enumerate(payload):
+            szl.Data[i] = b
+
+        result = parse_order_code_szl(szl)
+        self.assertEqual(result.OrderCode, b"6ES7 212-1BE40-0XB0")
+
     def test_parse_order_code_s71510sp(self) -> None:
         """Parse a real S7-1510SP dump — should use 0x0007 firmware, not 0x0081 boot loader.