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- // Copyright 2020 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 server
- import (
- "net"
- "strings"
- "sync"
- "time"
- "github.com/ethereum/go-ethereum/les/utils"
- "github.com/ethereum/go-ethereum/les/vflux"
- "github.com/ethereum/go-ethereum/log"
- "github.com/ethereum/go-ethereum/p2p/enode"
- "github.com/ethereum/go-ethereum/rlp"
- )
- type (
- // Server serves vflux requests
- Server struct {
- limiter *utils.Limiter
- lock sync.Mutex
- services map[string]*serviceEntry
- delayPerRequest time.Duration
- }
- // Service is a service registered at the Server and identified by a string id
- Service interface {
- Handle(id enode.ID, address string, name string, data []byte) []byte // never called concurrently
- }
- serviceEntry struct {
- id, desc string
- backend Service
- }
- )
- // NewServer creates a new Server
- func NewServer(delayPerRequest time.Duration) *Server {
- return &Server{
- limiter: utils.NewLimiter(1000),
- delayPerRequest: delayPerRequest,
- services: make(map[string]*serviceEntry),
- }
- }
- // Register registers a Service
- func (s *Server) Register(b Service, id, desc string) {
- srv := &serviceEntry{backend: b, id: id, desc: desc}
- if strings.Contains(srv.id, ":") {
- // srv.id + ":" will be used as a service database prefix
- log.Error("Service ID contains ':'", "id", srv.id)
- return
- }
- s.lock.Lock()
- s.services[srv.id] = srv
- s.lock.Unlock()
- }
- // Serve serves a vflux request batch
- // Note: requests are served by the Handle functions of the registered services. Serve
- // may be called concurrently but the Handle functions are called sequentially and
- // therefore thread safety is guaranteed.
- func (s *Server) Serve(id enode.ID, address string, requests vflux.Requests) vflux.Replies {
- reqLen := uint(len(requests))
- if reqLen == 0 || reqLen > vflux.MaxRequestLength {
- return nil
- }
- // Note: the value parameter will be supplied by the token sale module (total amount paid)
- ch := <-s.limiter.Add(id, address, 0, reqLen)
- if ch == nil {
- return nil
- }
- // Note: the limiter ensures that the following section is not running concurrently,
- // the lock only protects against contention caused by new service registration
- s.lock.Lock()
- results := make(vflux.Replies, len(requests))
- for i, req := range requests {
- if service := s.services[req.Service]; service != nil {
- results[i] = service.backend.Handle(id, address, req.Name, req.Params)
- }
- }
- s.lock.Unlock()
- time.Sleep(s.delayPerRequest * time.Duration(reqLen))
- close(ch)
- return results
- }
- // ServeEncoded serves an encoded vflux request batch and returns the encoded replies
- func (s *Server) ServeEncoded(id enode.ID, addr *net.UDPAddr, req []byte) []byte {
- var requests vflux.Requests
- if err := rlp.DecodeBytes(req, &requests); err != nil {
- return nil
- }
- results := s.Serve(id, addr.String(), requests)
- if results == nil {
- return nil
- }
- res, _ := rlp.EncodeToBytes(&results)
- return res
- }
- // Stop shuts down the server
- func (s *Server) Stop() {
- s.limiter.Stop()
- }
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