500 lines
17 KiB
Go
500 lines
17 KiB
Go
// Copyright 2017 The go-ethereum Authors
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// This file is part of go-ethereum.
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//
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// go-ethereum is free software: you can redistribute it and/or modify
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// it under the terms of the GNU 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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// go-ethereum 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 General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
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// faucet is a Ether faucet backed by a light client.
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package main
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//go:generate go-bindata -nometadata -o website.go faucet.html
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import (
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"bytes"
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"context"
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"encoding/json"
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"flag"
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"fmt"
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"html/template"
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"io/ioutil"
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"math/big"
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"net/http"
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"net/url"
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"os"
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"path/filepath"
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"strings"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/accounts"
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"github.com/ethereum/go-ethereum/accounts/keystore"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/eth"
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"github.com/ethereum/go-ethereum/eth/downloader"
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"github.com/ethereum/go-ethereum/ethclient"
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"github.com/ethereum/go-ethereum/ethstats"
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"github.com/ethereum/go-ethereum/les"
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"github.com/ethereum/go-ethereum/log"
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"github.com/ethereum/go-ethereum/node"
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"github.com/ethereum/go-ethereum/p2p"
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"github.com/ethereum/go-ethereum/p2p/discover"
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"github.com/ethereum/go-ethereum/p2p/discv5"
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"github.com/ethereum/go-ethereum/p2p/nat"
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"github.com/ethereum/go-ethereum/params"
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"golang.org/x/net/websocket"
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)
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var (
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genesisFlag = flag.String("genesis", "", "Genesis json file to seed the chain with")
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apiPortFlag = flag.Int("apiport", 8080, "Listener port for the HTTP API connection")
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ethPortFlag = flag.Int("ethport", 30303, "Listener port for the devp2p connection")
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bootFlag = flag.String("bootnodes", "", "Comma separated bootnode enode URLs to seed with")
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netFlag = flag.Uint64("network", 0, "Network ID to use for the Ethereum protocol")
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statsFlag = flag.String("ethstats", "", "Ethstats network monitoring auth string")
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netnameFlag = flag.String("faucet.name", "", "Network name to assign to the faucet")
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payoutFlag = flag.Int("faucet.amount", 1, "Number of Ethers to pay out per user request")
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minutesFlag = flag.Int("faucet.minutes", 1440, "Number of minutes to wait between funding rounds")
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accJSONFlag = flag.String("account.json", "", "Key json file to fund user requests with")
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accPassFlag = flag.String("account.pass", "", "Decryption password to access faucet funds")
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githubUser = flag.String("github.user", "", "GitHub user to authenticate with for Gist access")
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githubToken = flag.String("github.token", "", "GitHub personal token to access Gists with")
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captchaToken = flag.String("captcha.token", "", "Recaptcha site key to authenticate client side")
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captchaSecret = flag.String("captcha.secret", "", "Recaptcha secret key to authenticate server side")
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logFlag = flag.Int("loglevel", 3, "Log level to use for Ethereum and the faucet")
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)
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var (
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ether = new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil)
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)
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func main() {
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// Parse the flags and set up the logger to print everything requested
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flag.Parse()
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log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(*logFlag), log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
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// Load up and render the faucet website
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tmpl, err := Asset("faucet.html")
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if err != nil {
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log.Crit("Failed to load the faucet template", "err", err)
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}
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period := fmt.Sprintf("%d minute(s)", *minutesFlag)
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if *minutesFlag%60 == 0 {
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period = fmt.Sprintf("%d hour(s)", *minutesFlag/60)
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}
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website := new(bytes.Buffer)
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template.Must(template.New("").Parse(string(tmpl))).Execute(website, map[string]interface{}{
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"Network": *netnameFlag,
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"Amount": *payoutFlag,
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"Period": period,
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"Recaptcha": *captchaToken,
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})
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// Load and parse the genesis block requested by the user
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blob, err := ioutil.ReadFile(*genesisFlag)
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if err != nil {
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log.Crit("Failed to read genesis block contents", "genesis", *genesisFlag, "err", err)
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}
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genesis := new(core.Genesis)
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if err = json.Unmarshal(blob, genesis); err != nil {
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log.Crit("Failed to parse genesis block json", "err", err)
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}
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// Convert the bootnodes to internal enode representations
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var enodes []*discv5.Node
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for _, boot := range strings.Split(*bootFlag, ",") {
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if url, err := discv5.ParseNode(boot); err == nil {
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enodes = append(enodes, url)
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} else {
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log.Error("Failed to parse bootnode URL", "url", boot, "err", err)
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}
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}
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// Load up the account key and decrypt its password
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if blob, err = ioutil.ReadFile(*accPassFlag); err != nil {
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log.Crit("Failed to read account password contents", "file", *accPassFlag, "err", err)
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}
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pass := string(blob)
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ks := keystore.NewKeyStore(filepath.Join(os.Getenv("HOME"), ".faucet", "keys"), keystore.StandardScryptN, keystore.StandardScryptP)
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if blob, err = ioutil.ReadFile(*accJSONFlag); err != nil {
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log.Crit("Failed to read account key contents", "file", *accJSONFlag, "err", err)
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}
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acc, err := ks.Import(blob, pass, pass)
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if err != nil {
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log.Crit("Failed to import faucet signer account", "err", err)
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}
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ks.Unlock(acc, pass)
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// Assemble and start the faucet light service
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faucet, err := newFaucet(genesis, *ethPortFlag, enodes, *netFlag, *statsFlag, ks, website.Bytes())
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if err != nil {
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log.Crit("Failed to start faucet", "err", err)
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}
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defer faucet.close()
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if err := faucet.listenAndServe(*apiPortFlag); err != nil {
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log.Crit("Failed to launch faucet API", "err", err)
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}
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}
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// request represents an accepted funding request.
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type request struct {
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Username string `json:"username"` // GitHub user for displaying an avatar
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Account common.Address `json:"account"` // Ethereum address being funded
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Time time.Time `json:"time"` // Timestamp when te request was accepted
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Tx *types.Transaction `json:"tx"` // Transaction funding the account
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}
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// faucet represents a crypto faucet backed by an Ethereum light client.
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type faucet struct {
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config *params.ChainConfig // Chain configurations for signing
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stack *node.Node // Ethereum protocol stack
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client *ethclient.Client // Client connection to the Ethereum chain
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index []byte // Index page to serve up on the web
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keystore *keystore.KeyStore // Keystore containing the single signer
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account accounts.Account // Account funding user faucet requests
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nonce uint64 // Current pending nonce of the faucet
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price *big.Int // Current gas price to issue funds with
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conns []*websocket.Conn // Currently live websocket connections
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history map[string]time.Time // History of users and their funding requests
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reqs []*request // Currently pending funding requests
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update chan struct{} // Channel to signal request updates
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lock sync.RWMutex // Lock protecting the faucet's internals
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}
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func newFaucet(genesis *core.Genesis, port int, enodes []*discv5.Node, network uint64, stats string, ks *keystore.KeyStore, index []byte) (*faucet, error) {
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// Assemble the raw devp2p protocol stack
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stack, err := node.New(&node.Config{
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Name: "geth",
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Version: params.Version,
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DataDir: filepath.Join(os.Getenv("HOME"), ".faucet"),
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P2P: p2p.Config{
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NAT: nat.Any(),
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NoDiscovery: true,
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DiscoveryV5: true,
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ListenAddr: fmt.Sprintf(":%d", port),
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DiscoveryV5Addr: fmt.Sprintf(":%d", port+1),
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MaxPeers: 25,
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BootstrapNodesV5: enodes,
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},
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})
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if err != nil {
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return nil, err
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}
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// Assemble the Ethereum light client protocol
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if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
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cfg := eth.DefaultConfig
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cfg.SyncMode = downloader.LightSync
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cfg.NetworkId = network
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cfg.Genesis = genesis
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return les.New(ctx, &cfg)
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}); err != nil {
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return nil, err
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}
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// Assemble the ethstats monitoring and reporting service'
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if stats != "" {
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if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) {
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var serv *les.LightEthereum
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ctx.Service(&serv)
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return ethstats.New(stats, nil, serv)
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}); err != nil {
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return nil, err
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}
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}
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// Boot up the client and ensure it connects to bootnodes
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if err := stack.Start(); err != nil {
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return nil, err
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}
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for _, boot := range enodes {
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old, _ := discover.ParseNode(boot.String())
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stack.Server().AddPeer(old)
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}
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// Attach to the client and retrieve and interesting metadatas
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api, err := stack.Attach()
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if err != nil {
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stack.Stop()
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return nil, err
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}
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client := ethclient.NewClient(api)
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return &faucet{
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config: genesis.Config,
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stack: stack,
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client: client,
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index: index,
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keystore: ks,
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account: ks.Accounts()[0],
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history: make(map[string]time.Time),
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update: make(chan struct{}, 1),
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}, nil
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}
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// close terminates the Ethereum connection and tears down the faucet.
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func (f *faucet) close() error {
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return f.stack.Stop()
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}
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// listenAndServe registers the HTTP handlers for the faucet and boots it up
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// for service user funding requests.
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func (f *faucet) listenAndServe(port int) error {
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go f.loop()
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http.HandleFunc("/", f.webHandler)
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http.Handle("/api", websocket.Handler(f.apiHandler))
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return http.ListenAndServe(fmt.Sprintf(":%d", port), nil)
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}
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// webHandler handles all non-api requests, simply flattening and returning the
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// faucet website.
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func (f *faucet) webHandler(w http.ResponseWriter, r *http.Request) {
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w.Write(f.index)
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}
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// apiHandler handles requests for Ether grants and transaction statuses.
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func (f *faucet) apiHandler(conn *websocket.Conn) {
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// Start tracking the connection and drop at the end
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f.lock.Lock()
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f.conns = append(f.conns, conn)
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f.lock.Unlock()
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defer func() {
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f.lock.Lock()
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for i, c := range f.conns {
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if c == conn {
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f.conns = append(f.conns[:i], f.conns[i+1:]...)
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break
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}
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}
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f.lock.Unlock()
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}()
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// Send a few initial stats to the client
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balance, _ := f.client.BalanceAt(context.Background(), f.account.Address, nil)
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nonce, _ := f.client.NonceAt(context.Background(), f.account.Address, nil)
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websocket.JSON.Send(conn, map[string]interface{}{
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"funds": balance.Div(balance, ether),
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"funded": nonce,
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"peers": f.stack.Server().PeerCount(),
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"requests": f.reqs,
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})
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header, _ := f.client.HeaderByNumber(context.Background(), nil)
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websocket.JSON.Send(conn, header)
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// Keep reading requests from the websocket until the connection breaks
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for {
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// Fetch the next funding request and validate against github
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var msg struct {
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URL string `json:"url"`
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Captcha string `json:"captcha"`
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}
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if err := websocket.JSON.Receive(conn, &msg); err != nil {
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return
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}
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if !strings.HasPrefix(msg.URL, "https://gist.github.com/") {
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websocket.JSON.Send(conn, map[string]string{"error": "URL doesn't link to GitHub Gists"})
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continue
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}
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log.Info("Faucet funds requested", "gist", msg.URL)
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// If captcha verifications are enabled, make sure we're not dealing with a robot
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if *captchaToken != "" {
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form := url.Values{}
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form.Add("secret", *captchaSecret)
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form.Add("response", msg.Captcha)
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res, err := http.PostForm("https://www.google.com/recaptcha/api/siteverify", form)
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if err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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continue
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}
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var result struct {
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Success bool `json:"success"`
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Errors json.RawMessage `json:"error-codes"`
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}
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err = json.NewDecoder(res.Body).Decode(&result)
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res.Body.Close()
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if err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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continue
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}
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if !result.Success {
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log.Warn("Captcha verification failed", "err", string(result.Errors))
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websocket.JSON.Send(conn, map[string]string{"error": "Beep-boop, you're a robot!"})
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continue
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}
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}
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// Retrieve the gist from the GitHub Gist APIs
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parts := strings.Split(msg.URL, "/")
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req, _ := http.NewRequest("GET", "https://api.github.com/gists/"+parts[len(parts)-1], nil)
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if *githubUser != "" {
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req.SetBasicAuth(*githubUser, *githubToken)
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}
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res, err := http.DefaultClient.Do(req)
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if err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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continue
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}
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var gist struct {
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Owner struct {
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Login string `json:"login"`
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} `json:"owner"`
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Files map[string]struct {
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Content string `json:"content"`
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} `json:"files"`
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}
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err = json.NewDecoder(res.Body).Decode(&gist)
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res.Body.Close()
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if err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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continue
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}
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if gist.Owner.Login == "" {
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websocket.JSON.Send(conn, map[string]string{"error": "Anonymous Gists not allowed"})
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continue
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}
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// Iterate over all the files and look for Ethereum addresses
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var address common.Address
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for _, file := range gist.Files {
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if len(file.Content) == 2+common.AddressLength*2 {
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address = common.HexToAddress(file.Content)
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}
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}
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if address == (common.Address{}) {
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websocket.JSON.Send(conn, map[string]string{"error": "No Ethereum address found to fund"})
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continue
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}
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// Validate the user's existence since the API is unhelpful here
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if res, err = http.Head("https://github.com/" + gist.Owner.Login); err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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continue
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}
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res.Body.Close()
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if res.StatusCode != 200 {
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websocket.JSON.Send(conn, map[string]string{"error": "Invalid user... boom!"})
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continue
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}
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// Ensure the user didn't request funds too recently
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f.lock.Lock()
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var (
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fund bool
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elapsed time.Duration
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)
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if elapsed = time.Since(f.history[gist.Owner.Login]); elapsed > time.Duration(*minutesFlag)*time.Minute {
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// User wasn't funded recently, create the funding transaction
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tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, new(big.Int).Mul(big.NewInt(int64(*payoutFlag)), ether), big.NewInt(21000), f.price, nil)
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signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainId)
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if err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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f.lock.Unlock()
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continue
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}
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// Submit the transaction and mark as funded if successful
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if err := f.client.SendTransaction(context.Background(), signed); err != nil {
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websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
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f.lock.Unlock()
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continue
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}
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f.reqs = append(f.reqs, &request{
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Username: gist.Owner.Login,
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Account: address,
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Time: time.Now(),
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Tx: signed,
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})
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f.history[gist.Owner.Login] = time.Now()
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fund = true
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}
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f.lock.Unlock()
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// Send an error if too frequent funding, othewise a success
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if !fund {
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websocket.JSON.Send(conn, map[string]string{"error": fmt.Sprintf("User already funded %s ago", common.PrettyDuration(elapsed))})
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continue
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}
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websocket.JSON.Send(conn, map[string]string{"success": fmt.Sprintf("Funding request accepted for %s into %s", gist.Owner.Login, address.Hex())})
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select {
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case f.update <- struct{}{}:
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default:
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}
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}
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}
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// loop keeps waiting for interesting events and pushes them out to connected
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// websockets.
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func (f *faucet) loop() {
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// Wait for chain events and push them to clients
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heads := make(chan *types.Header, 16)
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sub, err := f.client.SubscribeNewHead(context.Background(), heads)
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if err != nil {
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log.Crit("Failed to subscribe to head events", "err", err)
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}
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defer sub.Unsubscribe()
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for {
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select {
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case head := <-heads:
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// New chain head arrived, query the current stats and stream to clients
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balance, _ := f.client.BalanceAt(context.Background(), f.account.Address, nil)
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balance = new(big.Int).Div(balance, ether)
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price, _ := f.client.SuggestGasPrice(context.Background())
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nonce, _ := f.client.NonceAt(context.Background(), f.account.Address, nil)
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f.lock.Lock()
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f.price, f.nonce = price, nonce
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for len(f.reqs) > 0 && f.reqs[0].Tx.Nonce() < f.nonce {
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f.reqs = f.reqs[1:]
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}
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f.lock.Unlock()
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|
|
f.lock.RLock()
|
|
for _, conn := range f.conns {
|
|
if err := websocket.JSON.Send(conn, map[string]interface{}{
|
|
"funds": balance,
|
|
"funded": f.nonce,
|
|
"peers": f.stack.Server().PeerCount(),
|
|
"requests": f.reqs,
|
|
}); err != nil {
|
|
log.Warn("Failed to send stats to client", "err", err)
|
|
conn.Close()
|
|
continue
|
|
}
|
|
if err := websocket.JSON.Send(conn, head); err != nil {
|
|
log.Warn("Failed to send header to client", "err", err)
|
|
conn.Close()
|
|
}
|
|
}
|
|
f.lock.RUnlock()
|
|
|
|
case <-f.update:
|
|
// Pending requests updated, stream to clients
|
|
f.lock.RLock()
|
|
for _, conn := range f.conns {
|
|
if err := websocket.JSON.Send(conn, map[string]interface{}{"requests": f.reqs}); err != nil {
|
|
log.Warn("Failed to send requests to client", "err", err)
|
|
conn.Close()
|
|
}
|
|
}
|
|
f.lock.RUnlock()
|
|
}
|
|
}
|
|
}
|