148 lines
4.5 KiB
Go
148 lines
4.5 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package rpc
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import (
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"context"
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"io"
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"sync/atomic"
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mapset "github.com/deckarep/golang-set"
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"github.com/ethereum/go-ethereum/log"
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)
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const MetadataApi = "rpc"
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// CodecOption specifies which type of messages a codec supports.
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//
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// Deprecated: this option is no longer honored by Server.
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type CodecOption int
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const (
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// OptionMethodInvocation is an indication that the codec supports RPC method calls
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OptionMethodInvocation CodecOption = 1 << iota
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// OptionSubscriptions is an indication that the codec supports RPC notifications
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OptionSubscriptions = 1 << iota // support pub sub
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)
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// Server is an RPC server.
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type Server struct {
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services serviceRegistry
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idgen func() ID
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run int32
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codecs mapset.Set
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}
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// NewServer creates a new server instance with no registered handlers.
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func NewServer() *Server {
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server := &Server{idgen: randomIDGenerator(), codecs: mapset.NewSet(), run: 1}
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// Register the default service providing meta information about the RPC service such
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// as the services and methods it offers.
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rpcService := &RPCService{server}
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server.RegisterName(MetadataApi, rpcService)
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return server
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}
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// RegisterName creates a service for the given receiver type under the given name. When no
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// methods on the given receiver match the criteria to be either a RPC method or a
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// subscription an error is returned. Otherwise a new service is created and added to the
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// service collection this server provides to clients.
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func (s *Server) RegisterName(name string, receiver interface{}) error {
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return s.services.registerName(name, receiver)
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}
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// ServeCodec reads incoming requests from codec, calls the appropriate callback and writes
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// the response back using the given codec. It will block until the codec is closed or the
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// server is stopped. In either case the codec is closed.
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//
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// Note that codec options are no longer supported.
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func (s *Server) ServeCodec(codec ServerCodec, options CodecOption) {
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defer codec.close()
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// Don't serve if server is stopped.
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if atomic.LoadInt32(&s.run) == 0 {
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return
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}
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// Add the codec to the set so it can be closed by Stop.
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s.codecs.Add(codec)
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defer s.codecs.Remove(codec)
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c := initClient(codec, s.idgen, &s.services)
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<-codec.closed()
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c.Close()
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}
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// serveSingleRequest reads and processes a single RPC request from the given codec. This
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// is used to serve HTTP connections. Subscriptions and reverse calls are not allowed in
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// this mode.
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func (s *Server) serveSingleRequest(ctx context.Context, codec ServerCodec) {
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// Don't serve if server is stopped.
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if atomic.LoadInt32(&s.run) == 0 {
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return
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}
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h := newHandler(ctx, codec, s.idgen, &s.services)
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h.allowSubscribe = false
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defer h.close(io.EOF, nil)
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reqs, batch, err := codec.readBatch()
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if err != nil {
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if err != io.EOF {
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codec.writeJSON(ctx, errorMessage(&invalidMessageError{"parse error"}))
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}
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return
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}
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if batch {
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h.handleBatch(reqs)
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} else {
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h.handleMsg(reqs[0])
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}
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}
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// Stop stops reading new requests, waits for stopPendingRequestTimeout to allow pending
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// requests to finish, then closes all codecs which will cancel pending requests and
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// subscriptions.
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func (s *Server) Stop() {
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if atomic.CompareAndSwapInt32(&s.run, 1, 0) {
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log.Debug("RPC server shutting down")
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s.codecs.Each(func(c interface{}) bool {
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c.(ServerCodec).close()
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return true
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})
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}
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}
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// RPCService gives meta information about the server.
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// e.g. gives information about the loaded modules.
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type RPCService struct {
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server *Server
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}
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// Modules returns the list of RPC services with their version number
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func (s *RPCService) Modules() map[string]string {
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s.server.services.mu.Lock()
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defer s.server.services.mu.Unlock()
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modules := make(map[string]string)
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for name := range s.server.services.services {
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modules[name] = "1.0"
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}
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return modules
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}
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