Fix: Trim whitespace from access code to prevent LAN auth failures #930

New Issue

MrUnknownDE · 2026-04-05T16:36:12+02:00

MrUnknownDE commented

2026-04-05 16:36:12 +02:00

Originally created by @myst3k on 1/31/2026

Fixes LAN connection failures caused by trailing whitespace in access codes received from Bambu printers via MQTT.

The Problem

When connecting to a Bambu printer in LAN mode, the printer sends the access code via MQTT with a trailing newline character (e.g., "9de74498\n"). This gets stored directly to the config file, causing
authentication to fail on subsequent connections because the 8-character code becomes 9 characters.

This manifests as OrcaSlicer repeatedly prompting for the LAN access code on every launch, even when credentials are correctly saved.

When This Started

The bug became visible after the Bambu Studio 1.8 beta merge (commit d8dd8fa634, Dec 2023), which added logic to refresh the access code from the printer via MQTT on every connection. The printer firmware
likely always sent the newline, but it wasn't stored until this refresh behavior was added.

Screenshots

Every Time I Opened

Video

https://github.com/user-attachments/assets/c4de806f-010a-43f6-9fa0-a1efcfcf68c3

The Fix

Trim whitespace in set_access_code() and set_user_access_code() before storing. This follows existing patterns in the codebase where boost::algorithm::trim() is used to sanitize input strings.

#6169 - "Orcaslicer forgets access code for X1C in LAN mode constantly" (closed, but root cause was not addressed)
#10534 - "Can't send prints to X1c in LAN mode" (possibly related)

Tests

Test 1: Upgrading from corrupted config

Created corrupted config in OrcaSlicer 2.3.1:
- Logged into Bambu cloud and synced
- This created access_code with newline: "9de74498\n"
- Both access_code and user_access_code became corrupted with \n
Closed 2.3.1
Opened fixed 2.3.2-dev build
Printer connected successfully (trim fix cleaned the value on load)
Close/reopen cycles - remained stable

Test 2: Fresh install with fix

Deleted OrcaSlicer config directory completely
Opened fixed 2.3.2-dev build
Completed setup wizard
Logged into Bambu cloud and synced
Connected to printer via SSDP
Config stored clean user_access_code without newline
Multiple close/reopen cycles - remained stable

Test 3: Reproduced original bug in 2.3.1

Confirmed the bug exists in 2.3.1:

Fresh config, logged into Bambu cloud, synced
access_code stored with \n suffix
Close/reopen resulted in "Incorrect password" error
Re-entering code manually only temporarily fixed it
user_access_code would get deleted or re-corrupted on subsequent close/reopen cycles

*Originally created by @myst3k on 1/31/2026* Fixes LAN connection failures caused by trailing whitespace in access codes received from Bambu printers via MQTT. ### The Problem When connecting to a Bambu printer in LAN mode, the printer sends the access code via MQTT with a trailing newline character (e.g., `"9de74498\n"`). This gets stored directly to the config file, causing authentication to fail on subsequent connections because the 8-character code becomes 9 characters. This manifests as OrcaSlicer repeatedly prompting for the LAN access code on every launch, even when credentials are correctly saved. ### When This Started The bug became visible after the Bambu Studio 1.8 beta merge (commit `d8dd8fa634`, Dec 2023), which added logic to refresh the access code from the printer via MQTT on every connection. The printer firmware likely always sent the newline, but it wasn't stored until this refresh behavior was added. ### Screenshots Every Time I Opened <img width="287" height="196" alt="image" src="https://github.com/user-attachments/assets/848aa51b-a2c8-4939-90ac-75f455af586e" /> ## Video https://github.com/user-attachments/assets/c4de806f-010a-43f6-9fa0-a1efcfcf68c3 ### The Fix Trim whitespace in `set_access_code()` and `set_user_access_code()` before storing. This follows existing patterns in the codebase where `boost::algorithm::trim()` is used to sanitize input strings. ### Related Issues - #6169 - "Orcaslicer forgets access code for X1C in LAN mode constantly" (closed, but root cause was not addressed) - #10534 - "Can't send prints to X1c in LAN mode" (possibly related) ## Tests ### Test 1: Upgrading from corrupted config 1. Created corrupted config in OrcaSlicer 2.3.1: - Logged into Bambu cloud and synced - This created `access_code` with newline: `"9de74498\n"` - Both `access_code` and `user_access_code` became corrupted with `\n` 2. Closed 2.3.1 3. Opened fixed 2.3.2-dev build 4. Printer connected successfully (trim fix cleaned the value on load) 5. Close/reopen cycles - remained stable ### Test 2: Fresh install with fix 1. Deleted OrcaSlicer config directory completely 2. Opened fixed 2.3.2-dev build 3. Completed setup wizard 4. Logged into Bambu cloud and synced 5. Connected to printer via SSDP 6. Config stored clean `user_access_code` without newline 7. Multiple close/reopen cycles - remained stable ### Test 3: Reproduced original bug in 2.3.1 Confirmed the bug exists in 2.3.1: 1. Fresh config, logged into Bambu cloud, synced 2. `access_code` stored with `\n` suffix 3. Close/reopen resulted in "Incorrect password" error 4. Re-entering code manually only temporarily fixed it 5. `user_access_code` would get deleted or re-corrupted on subsequent close/reopen cycles

MrUnknownDE closed this issue

2026-04-05 16:36:12 +02:00

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Reference: github/OrcaSlicer#930