// 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" "io" "sync/atomic" mapset "github.com/deckarep/golang-set" "github.com/ethereum/go-ethereum/log" ) const MetadataApi = "rpc" // CodecOption specifies which type of messages a codec supports. // // Deprecated: this option is no longer honored by Server. type CodecOption int const ( // OptionMethodInvocation is an indication that the codec supports RPC method calls OptionMethodInvocation CodecOption = 1 << iota // OptionSubscriptions is an indication that the codec supports RPC notifications OptionSubscriptions = 1 << iota // support pub sub ) // Server is an RPC server. type Server struct { services serviceRegistry idgen func() ID run int32 codecs mapset.Set } // NewServer creates a new server instance with no registered handlers. func NewServer() *Server { server := &Server{idgen: randomIDGenerator(), codecs: mapset.NewSet(), run: 1} // Register the default service providing meta information about the RPC service such // as the services and methods it offers. rpcService := &RPCService{server} server.RegisterName(MetadataApi, rpcService) return server } // RegisterName creates a service for the given receiver type under the given name. When no // methods on the given receiver match the criteria to be either a RPC method or a // subscription an error is returned. Otherwise a new service is created and added to the // service collection this server provides to clients. func (s *Server) RegisterName(name string, receiver interface{}) error { return s.services.registerName(name, receiver) } // ServeCodec reads incoming requests from codec, calls the appropriate callback and writes // the response back using the given codec. It will block until the codec is closed or the // server is stopped. In either case the codec is closed. // // Note that codec options are no longer supported. func (s *Server) ServeCodec(codec ServerCodec, options CodecOption) { defer codec.close() // Don't serve if server is stopped. if atomic.LoadInt32(&s.run) == 0 { return } // Add the codec to the set so it can be closed by Stop. s.codecs.Add(codec) defer s.codecs.Remove(codec) c := initClient(codec, s.idgen, &s.services) <-codec.closed() c.Close() } // serveSingleRequest reads and processes a single RPC request from the given codec. This // is used to serve HTTP connections. Subscriptions and reverse calls are not allowed in // this mode. func (s *Server) serveSingleRequest(ctx context.Context, codec ServerCodec) { // Don't serve if server is stopped. if atomic.LoadInt32(&s.run) == 0 { return } h := newHandler(ctx, codec, s.idgen, &s.services) h.allowSubscribe = false defer h.close(io.EOF, nil) reqs, batch, err := codec.readBatch() if err != nil { if err != io.EOF { codec.writeJSON(ctx, errorMessage(&invalidMessageError{"parse error"})) } return } if batch { h.handleBatch(reqs) } else { h.handleMsg(reqs[0]) } } // Stop stops reading new requests, waits for stopPendingRequestTimeout to allow pending // requests to finish, then closes all codecs which will cancel pending requests and // subscriptions. func (s *Server) Stop() { if atomic.CompareAndSwapInt32(&s.run, 1, 0) { log.Debug("RPC server shutting down") s.codecs.Each(func(c interface{}) bool { c.(ServerCodec).close() return true }) } } // RPCService gives meta information about the server. // e.g. gives information about the loaded modules. type RPCService struct { server *Server } // Modules returns the list of RPC services with their version number func (s *RPCService) Modules() map[string]string { s.server.services.mu.Lock() defer s.server.services.mu.Unlock() modules := make(map[string]string) for name := range s.server.services.services { modules[name] = "1.0" } return modules }