Crate connectrpc_reflection 

gRPC server reflection for connectrpc.

Wire-compatible with grpc.reflection.v1.ServerReflection and its v1alpha predecessor, so grpcurl, buf curl, Postman, grpcui, and every other reflection-aware client just works — over gRPC, gRPC-Web, and the Connect protocol alike.

Quick start

Emit a descriptor set from your build script alongside code generation:

// build.rs
connectrpc_build::Config::new()
    .files(&["proto/app.proto"])
    .includes(&["proto/"])
    .emit_descriptor_set("app.fds.bin")
    .compile()
    .unwrap();

then embed it and mount the service:

use connectrpc::Router;
use connectrpc_reflection::{Reflector, install};

// In real code: include_bytes!(concat!(env!("OUT_DIR"), "/app.fds.bin"))
let reflector = Reflector::from_descriptor_set_bytes(descriptor_set_bytes()).unwrap();
let router = install(Router::new(), reflector);

install registers both protocol versions; use the generated extension traits directly if you want only one.

Alternatively, when your buffa codegen has reflection enabled, skip the build-script step and serve straight from the generated package’s descriptor pool:

let reflector =
    Reflector::from_descriptor_pool(myapp::proto::descriptor_pool().clone()).unwrap();

The bytes path needs only emit_descriptor_set — reflection codegen is not required — and answers with the compiler’s original per-file descriptor bytes; the pool path re-encodes (semantically faithful, unknown fields preserved). See Reflector for the trade-off.

What gets exposed

Everything in the descriptor set: all files, their transitive imports, and every service compiled into it — whether or not the corresponding handlers are mounted on the router. Use Reflector::with_services to curate the advertised service list, and Reflector::service_names to inspect it. Build the set from the same protos you serve, and remember that reflection intentionally publishes your schema: gate or omit the service on deployments where that is not wanted.

The reflection service is self-describing: queries about grpc.reflection.* fall back to the crate’s own descriptors, and ListServices advertises the reflection services alongside yours. This matches grpc-go (where the reflection proto is always registered) and is what schema-free callers like buf curl need to invoke ServerReflectionInfo directly. Use Reflector::with_services to advertise a different list — the override is verbatim, so omitting the reflection names de-lists them (they stay resolvable as symbols).

Cargo features

• client (on by default) — re-exports the generated ServerReflectionClient for querying a reflection server (integration tests, CLI tooling). Pulls in connectrpc’s client feature; server-only deployments opt out with default-features = false.

Modules

wire

Re-exports of the generated grpc.reflection.* wire types — request and response messages, their oneof modules, and the method Spec constants. Everything a downstream crate needs to drive ServerReflectionClient (gated on the client feature) or inspect responses without regenerating the protos.

Structs

ReflectionService

gRPC-compatible server reflection service backed by a Reflector.

Reflector

Descriptor index serving gRPC server reflection queries.

ServerReflectionClientclient

Generated client for querying a grpc.reflection.v1.ServerReflection server. Client for this service.

Enums

ReflectionError

Errors from building a Reflector.

Constants

FILE_DESCRIPTOR_SET

The wire-format FileDescriptorSet for this crate’s protos (grpc.reflection.v1 and v1alpha, from the public Buf Schema Registry’s buf.build/grpc/grpc module).

SERVER_REFLECTION_SERVICE_NAME

Fully-qualified name of the v1 reflection service. Full service name for this service.

SERVER_REFLECTION_V1ALPHA_SERVICE_NAME

Fully-qualified name of the v1alpha reflection service. Full service name for this service.

Traits

ServerReflection

Generated v1 service trait and registration extension, for callers that mount a single protocol version by hand:

ServerReflectionExt

Generated v1 service trait and registration extension, for callers that mount a single protocol version by hand:

ServerReflectionV1alpha

Generated v1alpha service trait and registration extension, renamed to avoid colliding with the v1 items, for callers that mount the legacy protocol version by hand. Server trait for ServerReflection.

ServerReflectionV1alphaExt

Generated v1alpha service trait and registration extension, renamed to avoid colliding with the v1 items, for callers that mount the legacy protocol version by hand. Extension trait for registering a service implementation with a Router.

Functions

install

Register both protocol versions (v1 and v1alpha) on a router.