• Felix Lange's avatar
    rpc: implement full bi-directional communication (#18471) · 245f3146
    Felix Lange authored
    New APIs added:
    
        client.RegisterName(namespace, service) // makes service available to server
        client.Notify(ctx, method, args...)     // sends a notification
        ClientFromContext(ctx)                  // to get a client in handler method
    
    This is essentially a rewrite of the server-side code. JSON-RPC
    processing code is now the same on both server and client side. Many
    minor issues were fixed in the process and there is a new test suite for
    JSON-RPC spec compliance (and non-compliance in some cases).
    
    List of behavior changes:
    
    - Method handlers are now called with a per-request context instead of a
      per-connection context. The context is canceled right after the method
      returns.
    - Subscription error channels are always closed when the connection
      ends. There is no need to also wait on the Notifier's Closed channel
      to detect whether the subscription has ended.
    - Client now omits "params" instead of sending "params": null when there
      are no arguments to a call. The previous behavior was not compliant
      with the spec. The server still accepts "params": null.
    - Floating point numbers are allowed as "id". The spec doesn't allow
      them, but we handle request "id" as json.RawMessage and guarantee that
      the same number will be sent back.
    - Logging is improved significantly. There is now a message at DEBUG
      level for each RPC call served.
    245f3146
ipc.go 1.93 KB
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package rpc

import (
	"context"
	"net"

	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/p2p/netutil"
)

// ServeListener accepts connections on l, serving JSON-RPC on them.
func (s *Server) ServeListener(l net.Listener) error {
	for {
		conn, err := l.Accept()
		if netutil.IsTemporaryError(err) {
			log.Warn("RPC accept error", "err", err)
			continue
		} else if err != nil {
			return err
		}
		log.Trace("Accepted RPC connection", "conn", conn.RemoteAddr())
		go s.ServeCodec(NewJSONCodec(conn), OptionMethodInvocation|OptionSubscriptions)
	}
}

// DialIPC create a new IPC client that connects to the given endpoint. On Unix it assumes
// the endpoint is the full path to a unix socket, and Windows the endpoint is an
// identifier for a named pipe.
//
// The context is used for the initial connection establishment. It does not
// affect subsequent interactions with the client.
func DialIPC(ctx context.Context, endpoint string) (*Client, error) {
	return newClient(ctx, func(ctx context.Context) (ServerCodec, error) {
		conn, err := newIPCConnection(ctx, endpoint)
		if err != nil {
			return nil, err
		}
		return NewJSONCodec(conn), err
	})
}