node: allow websocket and HTTP on the same port (#20810)

This change makes it possible to run geth with JSON-RPC over HTTP and
WebSocket on the same TCP port. The default port for WebSocket
is still 8546. 

    geth --rpc --rpcport 8545 --ws --wsport 8545

This also removes a lot of deprecated API surface from package rpc.
The rpc package is now purely about serving JSON-RPC and no longer
provides a way to start an HTTP server.

node/endpoints.go

@@ -0,0 +1,99 @@
+// 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 node
+
+import (
+	"net"
+	"net/http"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+// StartHTTPEndpoint starts the HTTP RPC endpoint.
+func StartHTTPEndpoint(endpoint string, timeouts rpc.HTTPTimeouts, handler http.Handler) (net.Listener, error) {
+	// start the HTTP listener
+	var (
+		listener net.Listener
+		err      error
+	)
+	if listener, err = net.Listen("tcp", endpoint); err != nil {
+		return nil, err
+	}
+	// make sure timeout values are meaningful
+	CheckTimeouts(&timeouts)
+	// Bundle and start the HTTP server
+	httpSrv := &http.Server{
+		Handler:      handler,
+		ReadTimeout:  timeouts.ReadTimeout,
+		WriteTimeout: timeouts.WriteTimeout,
+		IdleTimeout:  timeouts.IdleTimeout,
+	}
+	go httpSrv.Serve(listener)
+	return listener, err
+}
+
+// startWSEndpoint starts a websocket endpoint.
+func startWSEndpoint(endpoint string, handler http.Handler) (net.Listener, error) {
+	// start the HTTP listener
+	var (
+		listener net.Listener
+		err      error
+	)
+	if listener, err = net.Listen("tcp", endpoint); err != nil {
+		return nil, err
+	}
+	wsSrv := &http.Server{Handler: handler}
+	go wsSrv.Serve(listener)
+	return listener, err
+}
+
+// checkModuleAvailability checks that all names given in modules are actually
+// available API services. It assumes that the MetadataApi module ("rpc") is always available;
+// the registration of this "rpc" module happens in NewServer() and is thus common to all endpoints.
+func checkModuleAvailability(modules []string, apis []rpc.API) (bad, available []string) {
+	availableSet := make(map[string]struct{})
+	for _, api := range apis {
+		if _, ok := availableSet[api.Namespace]; !ok {
+			availableSet[api.Namespace] = struct{}{}
+			available = append(available, api.Namespace)
+		}
+	}
+	for _, name := range modules {
+		if _, ok := availableSet[name]; !ok && name != rpc.MetadataApi {
+			bad = append(bad, name)
+		}
+	}
+	return bad, available
+}
+
+// CheckTimeouts ensures that timeout values are meaningful
+func CheckTimeouts(timeouts *rpc.HTTPTimeouts) {
+	if timeouts.ReadTimeout < time.Second {
+		log.Warn("Sanitizing invalid HTTP read timeout", "provided", timeouts.ReadTimeout, "updated", rpc.DefaultHTTPTimeouts.ReadTimeout)
+		timeouts.ReadTimeout = rpc.DefaultHTTPTimeouts.ReadTimeout
+	}
+	if timeouts.WriteTimeout < time.Second {
+		log.Warn("Sanitizing invalid HTTP write timeout", "provided", timeouts.WriteTimeout, "updated", rpc.DefaultHTTPTimeouts.WriteTimeout)
+		timeouts.WriteTimeout = rpc.DefaultHTTPTimeouts.WriteTimeout
+	}
+	if timeouts.IdleTimeout < time.Second {
+		log.Warn("Sanitizing invalid HTTP idle timeout", "provided", timeouts.IdleTimeout, "updated", rpc.DefaultHTTPTimeouts.IdleTimeout)
+		timeouts.IdleTimeout = rpc.DefaultHTTPTimeouts.IdleTimeout
+	}
+}