rpc_dart_grpc_reflection 0.4.0

gRPC Server Reflection (v1 + v1alpha) for rpc_dart. Allows grpcurl, Postman, and other gRPC tools to discover services registered on any rpc_dart endpoint.

rpc_dart_grpc_reflection

gRPC Server Reflection (v1 and v1alpha) for rpc_dart, so grpcurl, Postman and other gRPC tooling can list and describe the services of an endpoint.

• RpcReflectionRegistry — holds the FileDescriptorProto bytes to serve. attachTo(endpoint) registers the reflection service on an endpoint.
• ServerReflectionContract — the responder contract that answers reflection requests. attachTo registers two of them (ServerReflectionContract.both): grpc.reflection.v1.ServerReflection and grpc.reflection.v1alpha.ServerReflection.
• Descriptor sources:
  • addFromPbjson(...) — descriptor bytes from protoc-generated .pbjson.dart.
  • addFileDescriptor(bytes) — any serialized FileDescriptorProto, such as <Base>Names.grpcDescriptor emitted by rpc_dart_generator for @RpcService(grpcDescriptor: true).
  • RpcFileDescriptorBuilder with RpcMessageDescriptor, RpcMethodDescriptor, ... — hand-written schemas.

The registry serves only what is added to it. It does not read the contracts registered on the endpoint, so a service without a descriptor is not listed.

Usage

import 'package:rpc_dart_grpc_reflection/rpc_dart_grpc_reflection.dart';

final registry = RpcReflectionRegistry()..addFileDescriptor(descriptorBytes);
final missing = registry.missingDependencies(); // imported files not added

// Register your own contracts first, then reflection.
responderEndpoint.registerServiceContract(myResponderContract);
registry.attachTo(responderEndpoint);

With RpcHttp2Server, build the registry once and call attachTo inside the RpcResponderMode register; the server creates one endpoint per connection. Runnable servers are in example/server.dart (hand-built descriptor) and example/server_protobuf.dart (protoc descriptors and protobuf codecs).

Caveat

Reflection describes a protobuf schema. It is only truthful when the payloads on the wire really are protobuf — i.e. when the contract uses RpcBinaryCodec with protoc-generated messages. With the default CBOR codec (RpcCodec) the descriptors are advisory: tools list and describe the service, but a call from grpcurl sends protobuf the server cannot parse and fails with INTERNAL.