The bridge was falling back to mock mode with a confusing
'Cannot read properties of null (reading code)' error. The actual
underlying error (ECONNREFUSED, timeout, protocol mismatch) was
being swallowed by our error handler that did `(e as Error).message`
on a value that was sometimes null.
Wrap the kRPC client connect() in per-step try/catch with a
formatErr() helper that handles:
- null / undefined
- strings
- Error with .code (NodeJS.ErrnoException)
- arbitrary objects (JSON.stringify fallback)
Now when the bridge can't reach kRPC you get a real error like
'kRPC RPC TCP connect to 127.0.0.1:50000 failed: code=ECONNREFUSED:
connect ECONNREFUSED 127.0.0.1:50000' instead of the cryptic
null-code message.
Also fixed the bridge's main() error handler to be null-safe.
Discovered while debugging the user's first end-to-end run on
Windows: kRPC was reachable (Test-NetConnection succeeded) but
the bridge couldn't complete the handshake. With this fix we'll
see the real failure mode on the next attempt.
Built the missing piece that connects the ksp-bridge to a real KSP
instance via kRPC. This adds a typed service client on top of the
existing KRPCClient, plus the SpaceCenter-specific extraction logic
that pulls the universe state from a running KSP save.
@kerbal-rt/krpc-client
- types.ts — runtime representation of kRPC Type descriptors
(TypeCode enum, KrpcType interface, decodeKrpcType, typeName)
- decoder.ts — kRPC value codec: primitive decode/encode, class refs,
enums, collections (LIST/SET/TUPLE/DICTIONARY), system messages
(STATUS/SERVICES/STREAM/EVENT/PROCEDURE_CALL). 34 unit tests.
- services.ts — ServiceCache built from KRPC.GetServices() response.
Lookup by (service, procedure), enum value/name resolution. 12 tests.
- service-client.ts — KrpcServices: high-level invoke-by-name client.
loadServices() helper to connect + load catalog. 9 integration tests
with a mock kRPC server.
- schema.ts — added Set/Dictionary/Event/Expression types so the
decoder can handle system messages without external .proto files.
Also fixed a bug where 'STREAM' was being encoded as 0 due to
protobufjs's nested-enum string lookup.
ksp-bridge
- extract.ts — the actual SpaceCenter calls. ~280 procedure calls
per poll for a typical KSP save (UT, bodies, vessels, then per-body
and per-vessel class methods in parallel). Build the UniverseSnapshot.
- krpc-adapter.ts — rewrote to use KrpcServices (typed) instead of
the stub extract function. Supports an optional injected services
for testing.
- bridge.ts — uses the new ExtractedState type and buildSnapshot.
- index.ts — connects to kRPC; falls back to mock mode if no server.
- convert.ts — backward-compat shim, re-exports from extract.ts.
The ksp-bridge can now talk to a real KSP install. We do NOT need
the kRPC mod's .proto files on disk — the server's GetServices()
response is the source of truth for type info. Documented the full
list of procedures we call, the kRPC value encoding, and the new
architecture in ksp/README.md.
Tests: 119 total, all green. Typecheck and build clean across all 11
projects.
Bonus: fixed an integer-overflow bug in the krpc-client connect()
handshake (was passing 'RPC'/'STREAM' strings to protobufjs; its
nested-enum string lookup silently encodes as 0, which made the
stream handshake send the wrong type. Switched to numeric codes.)
- packages/krpc-client: TypeScript kRPC protocol client
- connection.ts: varint encoding/decoding, length-prefix framing,
per-socket read queue (avoids race when multiple read promises
in flight). Uses multiplication not '<<' for varint shift
because JS truncates << to 32 bits.
- schema.ts: hand-written protobufjs schema for kRPC meta-protocol
(ConnectionRequest, Request, Response, StreamUpdate, Status, etc.)
- enough to do connection handshake, single procedure calls, and
stream subscription. Service-specific types (SpaceCenter.Vessel,
Orbit, CelestialBody) need to be loaded from the kRPC mod's
.proto files at runtime.
- client.ts: KRPCClient with connect/invoke/addStream/removeStream/
onStreamUpdate/close. Tested with hand-rolled mock server.
- 10 tests (varint round-trips incl. uint64, wire format with raw
sockets).
- apps/tools/ksp-bridge: bridge that connects KSP to our API
- convert.ts: pure kRPC -> UniverseSnapshot conversion
(situation enum mapping, body id normalization, etc.)
- bridge.ts: main poll loop with retry + backoff
- krpc-adapter.ts: KRPCAdapter class that owns the KRPCClient
- index.ts: entrypoint with MOCK MODE for development (emits
synthetic state when no KSP is available, so you can verify the
HTTP pipeline end-to-end)
- 9 tests (7 conversion + 2 end-to-end bridge)
- ksp/README.md: full setup guide
- CKAN install, KSP server start, env vars
- Hand-rolled KSP calls list (what SpaceCenter methods we need)
- Roadmap for the remaining .proto-loading work
- Protocol deep-dive (for the next dev)
- Bug fixes along the way: protobufjs default import (not namespace),
varint 32-bit truncation, JavaScript bitwise 32-bit limit,
handshake status enum comparison (number vs string).
End-to-end verified: API + bridge in mock mode, 2 bodies + 1 vessel
arriving at /api/v1/state, 500ms polling cadence, automatic recovery
on HTTP failures.
Mavis