Module rpc::rpc

#include <std/rpc/rpc.h> source

RPC over HTTP (gRPC-inspired)

Not wire-compatible with real gRPC: real gRPC requires HTTP/2 (its framing and multiplexing model, plus trailer-carried status), which this module doesn't implement — std::http (see std/http/http.h) is HTTP/1.1 only. What IS reused from gRPC: the length-prefixed message envelope (1 compression-flag byte + 4-byte big-endian length + message bytes) and the "/Service/Method" path-routing convention, both carried inside a plain HTTP/1.1 POST request/response instead of an HTTP/2 stream. A real grpc-go/grpc-python/etc. client or server cannot talk to this one, and vice versa. If genuine gRPC wire compatibility is a hard requirement, this module isn't it — treat it as a same-shaped, HTTP/1.1-only RPC mechanism instead.

Message payloads are opaque bytes as far as this module is concerned — serialize/deserialize them yourself, e.g. with std::pb_write_/ std::PbReader (see std/serial/protobuf.h) for a real protobuf message, or any other format. Builds on std::http (see http.h's backend-selection note — a std/sched/io_nb_.sc backend must be included by the caller before this file too).

Structs

RpcResult

Type aliases

RpcMethodHandler A server-side method handler: given the raw (already-unframed) request bytes, return the raw response bytes to frame and send back. Set RpcResult::ok = 0 (with error_message) to report a failure — rpc_serve maps that to an HTTP error response rather than a 200.

Functions

rpc_call	Calls 'path' (e.g. "/Greeter/SayHello") at host:port with 'request_data'. On a transport-level failure (connect, non-200 response, malformed framing), the returned RpcResult has ok = 0 and error_message set; a handler-reported failure (server called RpcResult with ok=0) is surfaced the same way, with the handler's own error_message forwarded.
rpc_register	Registers 'handler' to be dispatched to for requests whose path exactly matches 'path'. Must be called (for every method the service exposes) before rpc_serve() — there is no dynamic registration after the accept loop starts.
rpc_serve	Blocking accept loop (like http_serve): for each request, looks up the registered handler for its path, unframes the body, calls the handler, frames its result, and sends the response back. A path with no registered handler gets HTTP 404. Returns -1 immediately if the listening socket can't be created; does not return otherwise.