244 lines
		
	
	
		
			7.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			244 lines
		
	
	
		
			7.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2018 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 rules
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import (
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	"encoding/json"
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	"fmt"
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	"os"
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	"strings"
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	"github.com/dop251/goja"
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	"github.com/ethereum/go-ethereum/internal/ethapi"
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	"github.com/ethereum/go-ethereum/internal/jsre/deps"
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	"github.com/ethereum/go-ethereum/log"
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	"github.com/ethereum/go-ethereum/signer/core"
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	"github.com/ethereum/go-ethereum/signer/storage"
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)
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var (
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	BigNumber_JS = deps.MustAsset("bignumber.js")
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)
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// consoleOutput is an override for the console.log and console.error methods to
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// stream the output into the configured output stream instead of stdout.
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func consoleOutput(call goja.FunctionCall) goja.Value {
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	output := []string{"JS:> "}
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	for _, argument := range call.Arguments {
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		output = append(output, fmt.Sprintf("%v", argument))
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	}
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	fmt.Fprintln(os.Stderr, strings.Join(output, " "))
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	return goja.Undefined()
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}
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// rulesetUI provides an implementation of UIClientAPI that evaluates a javascript
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// file for each defined UI-method
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type rulesetUI struct {
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	next    core.UIClientAPI // The next handler, for manual processing
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	storage storage.Storage
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	jsRules string // The rules to use
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}
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func NewRuleEvaluator(next core.UIClientAPI, jsbackend storage.Storage) (*rulesetUI, error) {
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	c := &rulesetUI{
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		next:    next,
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		storage: jsbackend,
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		jsRules: "",
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	}
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	return c, nil
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}
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func (r *rulesetUI) RegisterUIServer(api *core.UIServerAPI) {
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	// TODO, make it possible to query from js
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}
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func (r *rulesetUI) Init(javascriptRules string) error {
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	r.jsRules = javascriptRules
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	return nil
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}
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func (r *rulesetUI) execute(jsfunc string, jsarg interface{}) (goja.Value, error) {
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	// Instantiate a fresh vm engine every time
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	vm := goja.New()
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	// Set the native callbacks
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	consoleObj := vm.NewObject()
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	consoleObj.Set("log", consoleOutput)
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	consoleObj.Set("error", consoleOutput)
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	vm.Set("console", consoleObj)
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	storageObj := vm.NewObject()
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	storageObj.Set("put", func(call goja.FunctionCall) goja.Value {
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		key, val := call.Argument(0).String(), call.Argument(1).String()
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		if val == "" {
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			r.storage.Del(key)
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		} else {
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			r.storage.Put(key, val)
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		}
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		return goja.Null()
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	})
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	storageObj.Set("get", func(call goja.FunctionCall) goja.Value {
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		goval, _ := r.storage.Get(call.Argument(0).String())
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		jsval := vm.ToValue(goval)
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		return jsval
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	})
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	vm.Set("storage", storageObj)
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	// Load bootstrap libraries
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	script, err := goja.Compile("bignumber.js", string(BigNumber_JS), true)
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	if err != nil {
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		log.Warn("Failed loading libraries", "err", err)
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		return goja.Undefined(), err
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	}
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	vm.RunProgram(script)
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	// Run the actual rule implementation
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	_, err = vm.RunString(r.jsRules)
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	if err != nil {
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		log.Warn("Execution failed", "err", err)
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		return goja.Undefined(), err
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	}
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	// And the actual call
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	// All calls are objects with the parameters being keys in that object.
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	// To provide additional insulation between js and go, we serialize it into JSON on the Go-side,
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	// and deserialize it on the JS side.
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	jsonbytes, err := json.Marshal(jsarg)
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	if err != nil {
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		log.Warn("failed marshalling data", "data", jsarg)
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		return goja.Undefined(), err
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	}
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	// Now, we call foobar(JSON.parse(<jsondata>)).
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	var call string
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	if len(jsonbytes) > 0 {
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		call = fmt.Sprintf("%v(JSON.parse(%v))", jsfunc, string(jsonbytes))
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	} else {
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		call = fmt.Sprintf("%v()", jsfunc)
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	}
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	return vm.RunString(call)
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}
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func (r *rulesetUI) checkApproval(jsfunc string, jsarg []byte, err error) (bool, error) {
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	if err != nil {
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		return false, err
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	}
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	v, err := r.execute(jsfunc, string(jsarg))
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	if err != nil {
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		log.Info("error occurred during execution", "error", err)
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		return false, err
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	}
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	result := v.ToString().String()
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	if result == "Approve" {
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		log.Info("Op approved")
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		return true, nil
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	} else if result == "Reject" {
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		log.Info("Op rejected")
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		return false, nil
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	}
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	return false, fmt.Errorf("unknown response")
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}
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func (r *rulesetUI) ApproveTx(request *core.SignTxRequest) (core.SignTxResponse, error) {
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	jsonreq, err := json.Marshal(request)
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	approved, err := r.checkApproval("ApproveTx", jsonreq, err)
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	if err != nil {
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		log.Info("Rule-based approval error, going to manual", "error", err)
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		return r.next.ApproveTx(request)
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	}
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	if approved {
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		return core.SignTxResponse{
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				Transaction: request.Transaction,
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				Approved:    true},
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			nil
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	}
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	return core.SignTxResponse{Approved: false}, err
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}
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func (r *rulesetUI) ApproveSignData(request *core.SignDataRequest) (core.SignDataResponse, error) {
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	jsonreq, err := json.Marshal(request)
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	approved, err := r.checkApproval("ApproveSignData", jsonreq, err)
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	if err != nil {
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		log.Info("Rule-based approval error, going to manual", "error", err)
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		return r.next.ApproveSignData(request)
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	}
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	if approved {
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		return core.SignDataResponse{Approved: true}, nil
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	}
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	return core.SignDataResponse{Approved: false}, err
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}
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// OnInputRequired not handled by rules
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func (r *rulesetUI) OnInputRequired(info core.UserInputRequest) (core.UserInputResponse, error) {
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	return r.next.OnInputRequired(info)
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}
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func (r *rulesetUI) ApproveListing(request *core.ListRequest) (core.ListResponse, error) {
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	jsonreq, err := json.Marshal(request)
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	approved, err := r.checkApproval("ApproveListing", jsonreq, err)
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	if err != nil {
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		log.Info("Rule-based approval error, going to manual", "error", err)
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		return r.next.ApproveListing(request)
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	}
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	if approved {
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		return core.ListResponse{Accounts: request.Accounts}, nil
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	}
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	return core.ListResponse{}, err
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}
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func (r *rulesetUI) ApproveNewAccount(request *core.NewAccountRequest) (core.NewAccountResponse, error) {
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	// This cannot be handled by rules, requires setting a password
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	// dispatch to next
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	return r.next.ApproveNewAccount(request)
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}
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func (r *rulesetUI) ShowError(message string) {
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	log.Error(message)
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	r.next.ShowError(message)
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}
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func (r *rulesetUI) ShowInfo(message string) {
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	log.Info(message)
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	r.next.ShowInfo(message)
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}
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func (r *rulesetUI) OnSignerStartup(info core.StartupInfo) {
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	jsonInfo, err := json.Marshal(info)
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	if err != nil {
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		log.Warn("failed marshalling data", "data", info)
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		return
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	}
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	r.next.OnSignerStartup(info)
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	_, err = r.execute("OnSignerStartup", string(jsonInfo))
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	if err != nil {
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		log.Info("error occurred during execution", "error", err)
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	}
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}
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func (r *rulesetUI) OnApprovedTx(tx ethapi.SignTransactionResult) {
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	jsonTx, err := json.Marshal(tx)
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	if err != nil {
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		log.Warn("failed marshalling transaction", "tx", tx)
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		return
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	}
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	_, err = r.execute("OnApprovedTx", string(jsonTx))
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	if err != nil {
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		log.Info("error occurred during execution", "error", err)
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	}
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}
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