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// 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 useragent
import (
"encoding/json"
"fmt"
"net"
"github.com/ethereum/go-ethereum/accounts"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/rpc/shared"
)
// remoteFrontend implements xeth.Frontend and will communicate with an external
// user agent over a connection
type RemoteFrontend struct {
enabled bool
mgr *accounts.Manager
d *json.Decoder
e *json.Encoder
n int
}
// NewRemoteFrontend creates a new frontend which will interact with an user agent
// over the given connection
func NewRemoteFrontend(conn net.Conn, mgr *accounts.Manager) *RemoteFrontend {
return &RemoteFrontend{false, mgr, json.NewDecoder(conn), json.NewEncoder(conn), 0}
}
// Enable will enable user interaction
func (fe *RemoteFrontend) Enable() {
fe.enabled = true
}
// UnlockAccount asks the user agent for the user password and tries to unlock the account.
// It will try 3 attempts before giving up.
func (fe *RemoteFrontend) UnlockAccount(address []byte) bool {
if !fe.enabled {
return false
}
err := fe.send(AskPasswordMethod, common.Bytes2Hex(address))
if err != nil {
glog.V(logger.Error).Infof("Unable to send password request to agent - %v\n", err)
return false
}
passwdRes, err := fe.recv()
if err != nil {
glog.V(logger.Error).Infof("Unable to recv password response from agent - %v\n", err)
return false
}
if passwd, ok := passwdRes.Result.(string); ok {
err = fe.mgr.Unlock(common.BytesToAddress(address), passwd)
}
if err == nil {
return true
}
glog.V(logger.Debug).Infoln("3 invalid account unlock attempts")
return false
}
// ConfirmTransaction asks the user for approval
func (fe *RemoteFrontend) ConfirmTransaction(tx string) bool {
if !fe.enabled {
return true // backwards compatibility
}
err := fe.send(ConfirmTransactionMethod, tx)
if err != nil {
glog.V(logger.Error).Infof("Unable to send tx confirmation request to agent - %v\n", err)
return false
}
confirmResponse, err := fe.recv()
if err != nil {
glog.V(logger.Error).Infof("Unable to recv tx confirmation response from agent - %v\n", err)
return false
}
if confirmed, ok := confirmResponse.Result.(bool); ok {
return confirmed
}
return false
}
// send request to the agent
func (fe *RemoteFrontend) send(method string, params ...interface{}) error {
fe.n += 1
p, err := json.Marshal(params)
if err != nil {
glog.V(logger.Info).Infof("Unable to send agent request %v\n", err)
return err
}
req := shared.Request{
Method: method,
Jsonrpc: shared.JsonRpcVersion,
Id: fe.n,
Params: p,
}
return fe.e.Encode(&req)
}
// recv user response from agent
func (fe *RemoteFrontend) recv() (*shared.SuccessResponse, error) {
var res json.RawMessage
if err := fe.d.Decode(&res); err != nil {
return nil, err
}
var response shared.SuccessResponse
if err := json.Unmarshal(res, &response); err == nil {
return &response, nil
}
return nil, fmt.Errorf("Invalid user agent response")
}
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