• 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.
    Unverified
    245f3146
stdio.go 1.53 KB
// Copyright 2018 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"
	"errors"
	"net"
	"os"
	"time"
)

// DialStdIO creates a client on stdin/stdout.
func DialStdIO(ctx context.Context) (*Client, error) {
	return newClient(ctx, func(_ context.Context) (ServerCodec, error) {
		return NewJSONCodec(stdioConn{}), nil
	})
}

type stdioConn struct{}

func (io stdioConn) Read(b []byte) (n int, err error) {
	return os.Stdin.Read(b)
}

func (io stdioConn) Write(b []byte) (n int, err error) {
	return os.Stdout.Write(b)
}

func (io stdioConn) Close() error {
	return nil
}

func (io stdioConn) RemoteAddr() string {
	return "/dev/stdin"
}

func (io stdioConn) SetWriteDeadline(t time.Time) error {
	return &net.OpError{Op: "set", Net: "stdio", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
}