// Copyright 2017 The go-ethereum Authors // This file is part of go-ethereum. // // go-ethereum is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // go-ethereum 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 General Public License for more details. // // You should have received a copy of the GNU General Public License // along with go-ethereum. If not, see . // faucet is a Ether faucet backed by a light client. package main //go:generate go-bindata -nometadata -o website.go faucet.html //go:generate gofmt -w -s website.go import ( "bytes" "context" "encoding/json" "errors" "flag" "fmt" "html/template" "io/ioutil" "math" "math/big" "net/http" "net/url" "os" "path/filepath" "regexp" "strconv" "strings" "sync" "time" "github.com/ethereum/go-ethereum/accounts" "github.com/ethereum/go-ethereum/accounts/keystore" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/core" "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/eth" "github.com/ethereum/go-ethereum/eth/downloader" "github.com/ethereum/go-ethereum/ethclient" "github.com/ethereum/go-ethereum/ethstats" "github.com/ethereum/go-ethereum/les" "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/node" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/p2p/discover" "github.com/ethereum/go-ethereum/p2p/discv5" "github.com/ethereum/go-ethereum/p2p/nat" "github.com/ethereum/go-ethereum/params" "golang.org/x/net/websocket" ) var ( genesisFlag = flag.String("genesis", "", "Genesis json file to seed the chain with") apiPortFlag = flag.Int("apiport", 8080, "Listener port for the HTTP API connection") ethPortFlag = flag.Int("ethport", 30303, "Listener port for the devp2p connection") bootFlag = flag.String("bootnodes", "", "Comma separated bootnode enode URLs to seed with") netFlag = flag.Uint64("network", 0, "Network ID to use for the Ethereum protocol") statsFlag = flag.String("ethstats", "", "Ethstats network monitoring auth string") netnameFlag = flag.String("faucet.name", "", "Network name to assign to the faucet") payoutFlag = flag.Int("faucet.amount", 1, "Number of Ethers to pay out per user request") minutesFlag = flag.Int("faucet.minutes", 1440, "Number of minutes to wait between funding rounds") tiersFlag = flag.Int("faucet.tiers", 3, "Number of funding tiers to enable (x3 time, x2.5 funds)") accJSONFlag = flag.String("account.json", "", "Key json file to fund user requests with") accPassFlag = flag.String("account.pass", "", "Decryption password to access faucet funds") githubUser = flag.String("github.user", "", "GitHub user to authenticate with for Gist access") githubToken = flag.String("github.token", "", "GitHub personal token to access Gists with") captchaToken = flag.String("captcha.token", "", "Recaptcha site key to authenticate client side") captchaSecret = flag.String("captcha.secret", "", "Recaptcha secret key to authenticate server side") noauthFlag = flag.Bool("noauth", false, "Enables funding requests without authentication") logFlag = flag.Int("loglevel", 3, "Log level to use for Ethereum and the faucet") ) var ( ether = new(big.Int).Exp(big.NewInt(10), big.NewInt(18), nil) ) func main() { // Parse the flags and set up the logger to print everything requested flag.Parse() log.Root().SetHandler(log.LvlFilterHandler(log.Lvl(*logFlag), log.StreamHandler(os.Stderr, log.TerminalFormat(true)))) // Construct the payout tiers amounts := make([]string, *tiersFlag) periods := make([]string, *tiersFlag) for i := 0; i < *tiersFlag; i++ { // Calculate the amount for the next tier and format it amount := float64(*payoutFlag) * math.Pow(2.5, float64(i)) amounts[i] = fmt.Sprintf("%s Ethers", strconv.FormatFloat(amount, 'f', -1, 64)) if amount == 1 { amounts[i] = strings.TrimSuffix(amounts[i], "s") } // Calculate the period for the next tier and format it period := *minutesFlag * int(math.Pow(3, float64(i))) periods[i] = fmt.Sprintf("%d mins", period) if period%60 == 0 { period /= 60 periods[i] = fmt.Sprintf("%d hours", period) if period%24 == 0 { period /= 24 periods[i] = fmt.Sprintf("%d days", period) } } if period == 1 { periods[i] = strings.TrimSuffix(periods[i], "s") } } // Load up and render the faucet website tmpl, err := Asset("faucet.html") if err != nil { log.Crit("Failed to load the faucet template", "err", err) } website := new(bytes.Buffer) err = template.Must(template.New("").Parse(string(tmpl))).Execute(website, map[string]interface{}{ "Network": *netnameFlag, "Amounts": amounts, "Periods": periods, "Recaptcha": *captchaToken, "NoAuth": *noauthFlag, }) if err != nil { log.Crit("Failed to render the faucet template", "err", err) } // Load and parse the genesis block requested by the user blob, err := ioutil.ReadFile(*genesisFlag) if err != nil { log.Crit("Failed to read genesis block contents", "genesis", *genesisFlag, "err", err) } genesis := new(core.Genesis) if err = json.Unmarshal(blob, genesis); err != nil { log.Crit("Failed to parse genesis block json", "err", err) } // Convert the bootnodes to internal enode representations var enodes []*discv5.Node for _, boot := range strings.Split(*bootFlag, ",") { if url, err := discv5.ParseNode(boot); err == nil { enodes = append(enodes, url) } else { log.Error("Failed to parse bootnode URL", "url", boot, "err", err) } } // Load up the account key and decrypt its password if blob, err = ioutil.ReadFile(*accPassFlag); err != nil { log.Crit("Failed to read account password contents", "file", *accPassFlag, "err", err) } pass := string(blob) ks := keystore.NewKeyStore(filepath.Join(os.Getenv("HOME"), ".faucet", "keys"), keystore.StandardScryptN, keystore.StandardScryptP) if blob, err = ioutil.ReadFile(*accJSONFlag); err != nil { log.Crit("Failed to read account key contents", "file", *accJSONFlag, "err", err) } acc, err := ks.Import(blob, pass, pass) if err != nil { log.Crit("Failed to import faucet signer account", "err", err) } ks.Unlock(acc, pass) // Assemble and start the faucet light service faucet, err := newFaucet(genesis, *ethPortFlag, enodes, *netFlag, *statsFlag, ks, website.Bytes()) if err != nil { log.Crit("Failed to start faucet", "err", err) } defer faucet.close() if err := faucet.listenAndServe(*apiPortFlag); err != nil { log.Crit("Failed to launch faucet API", "err", err) } } // request represents an accepted funding request. type request struct { Avatar string `json:"avatar"` // Avatar URL to make the UI nicer Account common.Address `json:"account"` // Ethereum address being funded Time time.Time `json:"time"` // Timestamp when the request was accepted Tx *types.Transaction `json:"tx"` // Transaction funding the account } // faucet represents a crypto faucet backed by an Ethereum light client. type faucet struct { config *params.ChainConfig // Chain configurations for signing stack *node.Node // Ethereum protocol stack client *ethclient.Client // Client connection to the Ethereum chain index []byte // Index page to serve up on the web keystore *keystore.KeyStore // Keystore containing the single signer account accounts.Account // Account funding user faucet requests nonce uint64 // Current pending nonce of the faucet price *big.Int // Current gas price to issue funds with conns []*websocket.Conn // Currently live websocket connections timeouts map[string]time.Time // History of users and their funding timeouts reqs []*request // Currently pending funding requests update chan struct{} // Channel to signal request updates lock sync.RWMutex // Lock protecting the faucet's internals } func newFaucet(genesis *core.Genesis, port int, enodes []*discv5.Node, network uint64, stats string, ks *keystore.KeyStore, index []byte) (*faucet, error) { // Assemble the raw devp2p protocol stack stack, err := node.New(&node.Config{ Name: "geth", Version: params.Version, DataDir: filepath.Join(os.Getenv("HOME"), ".faucet"), P2P: p2p.Config{ NAT: nat.Any(), NoDiscovery: true, DiscoveryV5: true, ListenAddr: fmt.Sprintf(":%d", port), DiscoveryV5Addr: fmt.Sprintf(":%d", port+1), MaxPeers: 25, BootstrapNodesV5: enodes, }, }) if err != nil { return nil, err } // Assemble the Ethereum light client protocol if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) { cfg := eth.DefaultConfig cfg.SyncMode = downloader.LightSync cfg.NetworkId = network cfg.Genesis = genesis return les.New(ctx, &cfg) }); err != nil { return nil, err } // Assemble the ethstats monitoring and reporting service' if stats != "" { if err := stack.Register(func(ctx *node.ServiceContext) (node.Service, error) { var serv *les.LightEthereum ctx.Service(&serv) return ethstats.New(stats, nil, serv) }); err != nil { return nil, err } } // Boot up the client and ensure it connects to bootnodes if err := stack.Start(); err != nil { return nil, err } for _, boot := range enodes { old, _ := discover.ParseNode(boot.String()) stack.Server().AddPeer(old) } // Attach to the client and retrieve and interesting metadatas api, err := stack.Attach() if err != nil { stack.Stop() return nil, err } client := ethclient.NewClient(api) return &faucet{ config: genesis.Config, stack: stack, client: client, index: index, keystore: ks, account: ks.Accounts()[0], timeouts: make(map[string]time.Time), update: make(chan struct{}, 1), }, nil } // close terminates the Ethereum connection and tears down the faucet. func (f *faucet) close() error { return f.stack.Stop() } // listenAndServe registers the HTTP handlers for the faucet and boots it up // for service user funding requests. func (f *faucet) listenAndServe(port int) error { go f.loop() http.HandleFunc("/", f.webHandler) http.Handle("/api", websocket.Handler(f.apiHandler)) return http.ListenAndServe(fmt.Sprintf(":%d", port), nil) } // webHandler handles all non-api requests, simply flattening and returning the // faucet website. func (f *faucet) webHandler(w http.ResponseWriter, r *http.Request) { w.Write(f.index) } // apiHandler handles requests for Ether grants and transaction statuses. func (f *faucet) apiHandler(conn *websocket.Conn) { // Start tracking the connection and drop at the end defer conn.Close() f.lock.Lock() f.conns = append(f.conns, conn) f.lock.Unlock() defer func() { f.lock.Lock() for i, c := range f.conns { if c == conn { f.conns = append(f.conns[:i], f.conns[i+1:]...) break } } f.lock.Unlock() }() // Gather the initial stats from the network to report var ( head *types.Header balance *big.Int nonce uint64 err error ) for { // Attempt to retrieve the stats, may error on no faucet connectivity ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second) head, err = f.client.HeaderByNumber(ctx, nil) if err == nil { balance, err = f.client.BalanceAt(ctx, f.account.Address, head.Number) if err == nil { nonce, err = f.client.NonceAt(ctx, f.account.Address, nil) } } cancel() // If stats retrieval failed, wait a bit and retry if err != nil { if err = sendError(conn, errors.New("Faucet offline: "+err.Error())); err != nil { log.Warn("Failed to send faucet error to client", "err", err) return } time.Sleep(3 * time.Second) continue } // Initial stats reported successfully, proceed with user interaction break } // Send over the initial stats and the latest header if err = send(conn, map[string]interface{}{ "funds": balance.Div(balance, ether), "funded": nonce, "peers": f.stack.Server().PeerCount(), "requests": f.reqs, }, 3*time.Second); err != nil { log.Warn("Failed to send initial stats to client", "err", err) return } if err = send(conn, head, 3*time.Second); err != nil { log.Warn("Failed to send initial header to client", "err", err) return } // Keep reading requests from the websocket until the connection breaks for { // Fetch the next funding request and validate against github var msg struct { URL string `json:"url"` Tier uint `json:"tier"` Captcha string `json:"captcha"` } if err = websocket.JSON.Receive(conn, &msg); err != nil { return } if !*noauthFlag && !strings.HasPrefix(msg.URL, "https://gist.github.com/") && !strings.HasPrefix(msg.URL, "https://twitter.com/") && !strings.HasPrefix(msg.URL, "https://plus.google.com/") && !strings.HasPrefix(msg.URL, "https://www.facebook.com/") { if err = sendError(conn, errors.New("URL doesn't link to supported services")); err != nil { log.Warn("Failed to send URL error to client", "err", err) return } continue } if msg.Tier >= uint(*tiersFlag) { if err = sendError(conn, errors.New("Invalid funding tier requested")); err != nil { log.Warn("Failed to send tier error to client", "err", err) return } continue } log.Info("Faucet funds requested", "url", msg.URL, "tier", msg.Tier) // If captcha verifications are enabled, make sure we're not dealing with a robot if *captchaToken != "" { form := url.Values{} form.Add("secret", *captchaSecret) form.Add("response", msg.Captcha) res, err := http.PostForm("https://www.google.com/recaptcha/api/siteverify", form) if err != nil { if err = sendError(conn, err); err != nil { log.Warn("Failed to send captcha post error to client", "err", err) return } continue } var result struct { Success bool `json:"success"` Errors json.RawMessage `json:"error-codes"` } err = json.NewDecoder(res.Body).Decode(&result) res.Body.Close() if err != nil { if err = sendError(conn, err); err != nil { log.Warn("Failed to send captcha decode error to client", "err", err) return } continue } if !result.Success { log.Warn("Captcha verification failed", "err", string(result.Errors)) if err = sendError(conn, errors.New("Beep-bop, you're a robot!")); err != nil { log.Warn("Failed to send captcha failure to client", "err", err) return } continue } } // Retrieve the Ethereum address to fund, the requesting user and a profile picture var ( username string avatar string address common.Address ) switch { case strings.HasPrefix(msg.URL, "https://gist.github.com/"): if err = sendError(conn, errors.New("GitHub authentication discontinued at the official request of GitHub")); err != nil { log.Warn("Failed to send GitHub deprecation to client", "err", err) return } continue case strings.HasPrefix(msg.URL, "https://twitter.com/"): username, avatar, address, err = authTwitter(msg.URL) case strings.HasPrefix(msg.URL, "https://plus.google.com/"): username, avatar, address, err = authGooglePlus(msg.URL) case strings.HasPrefix(msg.URL, "https://www.facebook.com/"): username, avatar, address, err = authFacebook(msg.URL) case *noauthFlag: username, avatar, address, err = authNoAuth(msg.URL) default: err = errors.New("Something funky happened, please open an issue at https://github.com/ethereum/go-ethereum/issues") } if err != nil { if err = sendError(conn, err); err != nil { log.Warn("Failed to send prefix error to client", "err", err) return } continue } log.Info("Faucet request valid", "url", msg.URL, "tier", msg.Tier, "user", username, "address", address) // Ensure the user didn't request funds too recently f.lock.Lock() var ( fund bool timeout time.Time ) if timeout = f.timeouts[username]; time.Now().After(timeout) { // User wasn't funded recently, create the funding transaction amount := new(big.Int).Mul(big.NewInt(int64(*payoutFlag)), ether) amount = new(big.Int).Mul(amount, new(big.Int).Exp(big.NewInt(5), big.NewInt(int64(msg.Tier)), nil)) amount = new(big.Int).Div(amount, new(big.Int).Exp(big.NewInt(2), big.NewInt(int64(msg.Tier)), nil)) tx := types.NewTransaction(f.nonce+uint64(len(f.reqs)), address, amount, 21000, f.price, nil) signed, err := f.keystore.SignTx(f.account, tx, f.config.ChainId) if err != nil { f.lock.Unlock() if err = sendError(conn, err); err != nil { log.Warn("Failed to send transaction creation error to client", "err", err) return } continue } // Submit the transaction and mark as funded if successful if err := f.client.SendTransaction(context.Background(), signed); err != nil { f.lock.Unlock() if err = sendError(conn, err); err != nil { log.Warn("Failed to send transaction transmission error to client", "err", err) return } continue } f.reqs = append(f.reqs, &request{ Avatar: avatar, Account: address, Time: time.Now(), Tx: signed, }) f.timeouts[username] = time.Now().Add(time.Duration(*minutesFlag*int(math.Pow(3, float64(msg.Tier)))) * time.Minute) fund = true } f.lock.Unlock() // Send an error if too frequent funding, othewise a success if !fund { if err = sendError(conn, fmt.Errorf("%s left until next allowance", common.PrettyDuration(timeout.Sub(time.Now())))); err != nil { // nolint: gosimple log.Warn("Failed to send funding error to client", "err", err) return } continue } if err = sendSuccess(conn, fmt.Sprintf("Funding request accepted for %s into %s", username, address.Hex())); err != nil { log.Warn("Failed to send funding success to client", "err", err) return } select { case f.update <- struct{}{}: default: } } } // loop keeps waiting for interesting events and pushes them out to connected // websockets. func (f *faucet) loop() { // Wait for chain events and push them to clients heads := make(chan *types.Header, 16) sub, err := f.client.SubscribeNewHead(context.Background(), heads) if err != nil { log.Crit("Failed to subscribe to head events", "err", err) } defer sub.Unsubscribe() for { select { case head := <-heads: // New chain head arrived, query the current stats and stream to clients var ( balance *big.Int nonce uint64 price *big.Int err error ) ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second) balance, err = f.client.BalanceAt(ctx, f.account.Address, head.Number) if err == nil { nonce, err = f.client.NonceAt(ctx, f.account.Address, nil) if err == nil { price, err = f.client.SuggestGasPrice(ctx) } } cancel() // If querying the data failed, try for the next block if err != nil { log.Warn("Failed to update faucet state", "block", head.Number, "hash", head.Hash(), "err", err) continue } else { log.Info("Updated faucet state", "block", head.Number, "hash", head.Hash(), "balance", balance, "nonce", nonce, "price", price) } // Faucet state retrieved, update locally and send to clients balance = new(big.Int).Div(balance, ether) f.lock.Lock() f.price, f.nonce = price, nonce for len(f.reqs) > 0 && f.reqs[0].Tx.Nonce() < f.nonce { f.reqs = f.reqs[1:] } f.lock.Unlock() f.lock.RLock() for _, conn := range f.conns { if err := send(conn, map[string]interface{}{ "funds": balance, "funded": f.nonce, "peers": f.stack.Server().PeerCount(), "requests": f.reqs, }, time.Second); err != nil { log.Warn("Failed to send stats to client", "err", err) conn.Close() continue } if err := send(conn, head, time.Second); 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 := send(conn, map[string]interface{}{"requests": f.reqs}, time.Second); err != nil { log.Warn("Failed to send requests to client", "err", err) conn.Close() } } f.lock.RUnlock() } } } // sends transmits a data packet to the remote end of the websocket, but also // setting a write deadline to prevent waiting forever on the node. func send(conn *websocket.Conn, value interface{}, timeout time.Duration) error { if timeout == 0 { timeout = 60 * time.Second } conn.SetWriteDeadline(time.Now().Add(timeout)) return websocket.JSON.Send(conn, value) } // sendError transmits an error to the remote end of the websocket, also setting // the write deadline to 1 second to prevent waiting forever. func sendError(conn *websocket.Conn, err error) error { return send(conn, map[string]string{"error": err.Error()}, time.Second) } // sendSuccess transmits a success message to the remote end of the websocket, also // setting the write deadline to 1 second to prevent waiting forever. func sendSuccess(conn *websocket.Conn, msg string) error { return send(conn, map[string]string{"success": msg}, time.Second) } // authGitHub tries to authenticate a faucet request using GitHub gists, returning // the username, avatar URL and Ethereum address to fund on success. func authGitHub(url string) (string, string, common.Address, error) { // Retrieve the gist from the GitHub Gist APIs parts := strings.Split(url, "/") req, _ := http.NewRequest("GET", "https://api.github.com/gists/"+parts[len(parts)-1], nil) if *githubUser != "" { req.SetBasicAuth(*githubUser, *githubToken) } res, err := http.DefaultClient.Do(req) if err != nil { return "", "", common.Address{}, err } var gist struct { Owner struct { Login string `json:"login"` } `json:"owner"` Files map[string]struct { Content string `json:"content"` } `json:"files"` } err = json.NewDecoder(res.Body).Decode(&gist) res.Body.Close() if err != nil { return "", "", common.Address{}, err } if gist.Owner.Login == "" { return "", "", common.Address{}, errors.New("Anonymous Gists not allowed") } // Iterate over all the files and look for Ethereum addresses var address common.Address for _, file := range gist.Files { content := strings.TrimSpace(file.Content) if len(content) == 2+common.AddressLength*2 { address = common.HexToAddress(content) } } if address == (common.Address{}) { return "", "", common.Address{}, errors.New("No Ethereum address found to fund") } // Validate the user's existence since the API is unhelpful here if res, err = http.Head("https://github.com/" + gist.Owner.Login); err != nil { return "", "", common.Address{}, err } res.Body.Close() if res.StatusCode != 200 { return "", "", common.Address{}, errors.New("Invalid user... boom!") } // Everything passed validation, return the gathered infos return gist.Owner.Login + "@github", fmt.Sprintf("https://github.com/%s.png?size=64", gist.Owner.Login), address, nil } // authTwitter tries to authenticate a faucet request using Twitter posts, returning // the username, avatar URL and Ethereum address to fund on success. func authTwitter(url string) (string, string, common.Address, error) { // Ensure the user specified a meaningful URL, no fancy nonsense parts := strings.Split(url, "/") if len(parts) < 4 || parts[len(parts)-2] != "status" { return "", "", common.Address{}, errors.New("Invalid Twitter status URL") } username := parts[len(parts)-3] // Twitter's API isn't really friendly with direct links. Still, we don't // want to do ask read permissions from users, so just load the public posts and // scrape it for the Ethereum address and profile URL. res, err := http.Get(url) if err != nil { return "", "", common.Address{}, err } defer res.Body.Close() body, err := ioutil.ReadAll(res.Body) if err != nil { return "", "", common.Address{}, err } address := common.HexToAddress(string(regexp.MustCompile("0x[0-9a-fA-F]{40}").Find(body))) if address == (common.Address{}) { return "", "", common.Address{}, errors.New("No Ethereum address found to fund") } var avatar string if parts = regexp.MustCompile("src=\"([^\"]+twimg.com/profile_images[^\"]+)\"").FindStringSubmatch(string(body)); len(parts) == 2 { avatar = parts[1] } return username + "@twitter", avatar, address, nil } // authGooglePlus tries to authenticate a faucet request using GooglePlus posts, // returning the username, avatar URL and Ethereum address to fund on success. func authGooglePlus(url string) (string, string, common.Address, error) { // Ensure the user specified a meaningful URL, no fancy nonsense parts := strings.Split(url, "/") if len(parts) < 4 || parts[len(parts)-2] != "posts" { return "", "", common.Address{}, errors.New("Invalid Google+ post URL") } username := parts[len(parts)-3] // Google's API isn't really friendly with direct links. Still, we don't // want to do ask read permissions from users, so just load the public posts and // scrape it for the Ethereum address and profile URL. res, err := http.Get(url) if err != nil { return "", "", common.Address{}, err } defer res.Body.Close() body, err := ioutil.ReadAll(res.Body) if err != nil { return "", "", common.Address{}, err } address := common.HexToAddress(string(regexp.MustCompile("0x[0-9a-fA-F]{40}").Find(body))) if address == (common.Address{}) { return "", "", common.Address{}, errors.New("No Ethereum address found to fund") } var avatar string if parts = regexp.MustCompile("src=\"([^\"]+googleusercontent.com[^\"]+photo.jpg)\"").FindStringSubmatch(string(body)); len(parts) == 2 { avatar = parts[1] } return username + "@google+", avatar, address, nil } // authFacebook tries to authenticate a faucet request using Facebook posts, // returning the username, avatar URL and Ethereum address to fund on success. func authFacebook(url string) (string, string, common.Address, error) { // Ensure the user specified a meaningful URL, no fancy nonsense parts := strings.Split(url, "/") if len(parts) < 4 || parts[len(parts)-2] != "posts" { return "", "", common.Address{}, errors.New("Invalid Facebook post URL") } username := parts[len(parts)-3] // Facebook's Graph API isn't really friendly with direct links. Still, we don't // want to do ask read permissions from users, so just load the public posts and // scrape it for the Ethereum address and profile URL. res, err := http.Get(url) if err != nil { return "", "", common.Address{}, err } defer res.Body.Close() body, err := ioutil.ReadAll(res.Body) if err != nil { return "", "", common.Address{}, err } address := common.HexToAddress(string(regexp.MustCompile("0x[0-9a-fA-F]{40}").Find(body))) if address == (common.Address{}) { return "", "", common.Address{}, errors.New("No Ethereum address found to fund") } var avatar string if parts = regexp.MustCompile("src=\"([^\"]+fbcdn.net[^\"]+)\"").FindStringSubmatch(string(body)); len(parts) == 2 { avatar = parts[1] } return username + "@facebook", avatar, address, nil } // authNoAuth tries to interpret a faucet request as a plain Ethereum address, // without actually performing any remote authentication. This mode is prone to // Byzantine attack, so only ever use for truly private networks. func authNoAuth(url string) (string, string, common.Address, error) { address := common.HexToAddress(regexp.MustCompile("0x[0-9a-fA-F]{40}").FindString(url)) if address == (common.Address{}) { return "", "", common.Address{}, errors.New("No Ethereum address found to fund") } return address.Hex() + "@noauth", "", address, nil }