Same override pattern as connect(): required, no default body, five
completely different bodies.
- BambuGenericPrinter::set_fan_speed_impl() is shared by BambuV1Printer and
BambuV2Printer (composition reuse, same as connect_impl) - both speak
the same MQTT gcode-injection mechanism.
- PrusaLinkPrinter and PrusaSerialPrinter both send the same M106 gcode
but over different transports (HTTP command injection vs. raw serial
bytes) - they share the percent->PWM conversion despite having unrelated
connect() implementations.
- KlipperPrinter uses a hypothetical Moonraker-native endpoint that takes
a percentage directly - no PWM conversion at all, since that math only
applies to the gcode-speaking vendors.
percent_to_pwm() lives in mod.rs as a private free function rather than a
trait default: it's genuine shared logic, but only for the subset of
vendors that need it, which is exactly the case a trait default can't
express cleanly. Visible to bambu.rs/prusa.rs via super:: because Rust's
module privacy reaches into child modules.
Verified with cargo check --all-targets and a full run of
printer_polymorphism: 50% converges on the same PWM value (127) across all
three gcode-based printers, Klipper's native path takes 0.50 directly.
Completes the GenericPrinter -> BambuGenericPrinter -> BambuV1/V2 chain this
project wanted from the start. BambuGenericPrinter holds the fields and
behavior every Bambu printer shares (access code, serial number, CA trust,
the TLS test/fetch methods); BambuV1Printer and BambuV2Printer each *have*
one (composition) and are now genuinely separate types, ready to carry
flavour-specific report-schema fields later. Also threads through a new
'sn' (serial number) field the real MQTT topics will need.
Adds real 'fetch the CA automatically' capability, verified against a live
TLS server (not just compiled):
- BambuGenericPrinter::fetch_certificate() does trust-on-first-connect —
connects once with verification disabled, captures the certificate the
printer actually presents via native_tls's peer_certificate()/to_der(),
and returns it as PEM. Deliberately a method you call once by hand
(examples/fetch_bambu_cert.rs), not something connect() falls back to
silently, since TOFU trusts whoever's on the network the moment you run
it. Verified end-to-end against a local openssl s_server: the fetched
PEM's SHA-256 fingerprint exactly matched the server's real certificate.
- Verified the other direction too: test_bambu_certs (bundled-CA mode)
correctly REJECTS that same test server's cert, since it wasn't signed
by the real Bambu CA.
Splitting BambuV1Printer/BambuV2Printer into distinct types broke the
PrinterHandle::BambuV1(x) | PrinterHandle::BambuV2(x) or-pattern in both
examples (or-patterns require every alternative to bind the same type) —
fixed by giving each variant its own match arm.
Certs:
- Vendor Bambu's shared LAN-mode root CA (certs/bambu_ca2.pem, verified
self-signed CA:TRUE, see certs/README.md for provenance/fingerprint).
- Config gains bambu_ca_cert_path (per-printer override) and
bambu_require_valid_cert (the allow/reject flag); printer::bambu::BambuTls
turns those into BundledCa/Custom/Insecure. connect() doesn't perform a
real handshake yet (no TLS-capable MQTT client wired in), just reports
which trust mode it would use.
Also reconciles a rename in flight (Printer -> GenericPrinter trait) and
finishes the PrusaPrinter -> PrusaLinkPrinter/PrusaSerialPrinter split:
added the missing GenericPrinter impl for PrusaSerialPrinter, fixed
PrinterHandle's variant payload types, updated mod.rs's pub use list and
doc comments, and updated the example to the new 5-variant shape.
Verified with cargo check --all-targets (0 errors) and a full run of
cargo run --example printer_polymorphism.
Drop reqwest, RPITIT+Send signature, and multi-variant error enum from the
teaching example so the only new idea per file is the trait override itself.
Real networking stays in adapters/, unaffected.
octoturge
