path: root/console/console.go

// 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 console

import (
    "fmt"
    "io"
    "io/ioutil"
    "os"
    "os/signal"
    "path/filepath"
    "regexp"
    "sort"
    "strings"

    "github.com/ethereum/go-ethereum/internal/jsre"
    "github.com/ethereum/go-ethereum/internal/web3ext"
    "github.com/ethereum/go-ethereum/rpc"
    "github.com/peterh/liner"
    "github.com/robertkrimen/otto"
)

var (
    passwordRegexp = regexp.MustCompile("personal.[nus]")
    onlyWhitespace = regexp.MustCompile("^\\s*$")
    exit           = regexp.MustCompile("^\\s*exit\\s*;*\\s*$")
)

// HistoryFile is the file within the data directory to store input scrollback.
const HistoryFile = "history"

// DefaultPrompt is the default prompt line prefix to use for user input querying.
const DefaultPrompt = "> "

// Config is te collection of configurations to fine tune the behavior of the
// JavaScript console.
type Config struct {
    DataDir  string       // Data directory to store the console history at
    DocRoot  string       // Filesystem path from where to load JavaScript files from
    Client   rpc.Client   // RPC client to execute Ethereum requests through
    Prompt   string       // Input prompt prefix string (defaults to DefaultPrompt)
    Prompter UserPrompter // Input prompter to allow interactive user feedback (defaults to TerminalPrompter)
    Printer  io.Writer    // Output writer to serialize any display strings to (defaults to os.Stdout)
    Preload  []string     // Absolute paths to JavaScript files to preload
}

// Console is a JavaScript interpreted runtime environment. It is a fully fleged
// JavaScript console attached to a running node via an external or in-process RPC
// client.
type Console struct {
    client   rpc.Client   // RPC client to execute Ethereum requests through
    jsre     *jsre.JSRE   // JavaScript runtime environment running the interpreter
    prompt   string       // Input prompt prefix string
    prompter UserPrompter // Input prompter to allow interactive user feedback
    histPath string       // Absolute path to the console scrollback history
    history  []string     // Scroll history maintained by the console
    printer  io.Writer    // Output writer to serialize any display strings to
}

func New(config Config) (*Console, error) {
    // Handle unset config values gracefully
    if config.Prompter == nil {
        config.Prompter = Stdin
    }
    if config.Prompt == "" {
        config.Prompt = DefaultPrompt
    }
    if config.Printer == nil {
        config.Printer = os.Stdout
    }
    // Initialize the console and return
    console := &Console{
        client:   config.Client,
        jsre:     jsre.New(config.DocRoot, config.Printer),
        prompt:   config.Prompt,
        prompter: config.Prompter,
        printer:  config.Printer,
        histPath: filepath.Join(config.DataDir, HistoryFile),
    }
    if err := console.init(config.Preload); err != nil {
        return nil, err
    }
    return console, nil
}

// init retrieves the available APIs from the remote RPC provider and initializes
// the console's JavaScript namespaces based on the exposed modules.
func (c *Console) init(preload []string) error {
    // Initialize the JavaScript <-> Go RPC bridge
    bridge := newBridge(c.client, c.prompter, c.printer)
    c.jsre.Set("jeth", struct{}{})

    jethObj, _ := c.jsre.Get("jeth")
    jethObj.Object().Set("send", bridge.Send)
    jethObj.Object().Set("sendAsync", bridge.Send)

    consoleObj, _ := c.jsre.Get("console")
    consoleObj.Object().Set("log", c.consoleOutput)
    consoleObj.Object().Set("error", c.consoleOutput)

    // Load all the internal utility JavaScript libraries
    if err := c.jsre.Compile("bignumber.js", jsre.BigNumber_JS); err != nil {
        return fmt.Errorf("bignumber.js: %v", err)
    }
    if err := c.jsre.Compile("web3.js", jsre.Web3_JS); err != nil {
        return fmt.Errorf("web3.js: %v", err)
    }
    if _, err := c.jsre.Run("var Web3 = require('web3');"); err != nil {
        return fmt.Errorf("web3 require: %v", err)
    }
    if _, err := c.jsre.Run("var web3 = new Web3(jeth);"); err != nil {
        return fmt.Errorf("web3 provider: %v", err)
    }
    // Load the supported APIs into the JavaScript runtime environment
    apis, err := c.client.SupportedModules()
    if err != nil {
        return fmt.Errorf("api modules: %v", err)
    }
    flatten := "var eth = web3.eth; var personal = web3.personal; "
    for api := range apis {
        if api == "web3" {
            continue // manually mapped or ignore
        }
        if file, ok := web3ext.Modules[api]; ok {
            if err = c.jsre.Compile(fmt.Sprintf("%s.js", api), file); err != nil {
                return fmt.Errorf("%s.js: %v", api, err)
            }
            flatten += fmt.Sprintf("var %s = web3.%s; ", api, api)
        }
    }
    if _, err = c.jsre.Run(flatten); err != nil {
        return fmt.Errorf("namespace flattening: %v", err)
    }
    // Initialize the global name register (disabled for now)
    //c.jsre.Run(`var GlobalRegistrar = eth.contract(` + registrar.GlobalRegistrarAbi + `);   registrar = GlobalRegistrar.at("` + registrar.GlobalRegistrarAddr + `");`)

    // If the console is in interactive mode, instrument password related methods to query the user
    if c.prompter != nil {
        // Retrieve the account management object to instrument
        personal, err := c.jsre.Get("personal")
        if err != nil {
            return err
        }
        // Override the unlockAccount and newAccount methods since these require user interaction.
        // Assign the jeth.unlockAccount and jeth.newAccount in the Console the original web3 callbacks.
        // These will be called by the jeth.* methods after they got the password from the user and send
        // the original web3 request to the backend.
        if obj := personal.Object(); obj != nil { // make sure the personal api is enabled over the interface
            if _, err = c.jsre.Run(`jeth.unlockAccount = personal.unlockAccount;`); err != nil {
                return fmt.Errorf("personal.unlockAccount: %v", err)
            }
            if _, err = c.jsre.Run(`jeth.newAccount = personal.newAccount;`); err != nil {
                return fmt.Errorf("personal.newAccount: %v", err)
            }
            obj.Set("unlockAccount", bridge.UnlockAccount)
            obj.Set("newAccount", bridge.NewAccount)
        }
    }
    // The admin.sleep and admin.sleepBlocks are offered by the console and not by the RPC layer.
    admin, err := c.jsre.Get("admin")
    if err != nil {
        return err
    }
    if obj := admin.Object(); obj != nil { // make sure the admin api is enabled over the interface
        obj.Set("sleepBlocks", bridge.SleepBlocks)
        obj.Set("sleep", bridge.Sleep)
    }
    // Preload any JavaScript files before starting the console
    for _, path := range preload {
        if err := c.jsre.Exec(path); err != nil {
            failure := err.Error()
            if ottoErr, ok := err.(*otto.Error); ok {
                failure = ottoErr.String()
            }
            return fmt.Errorf("%s: %v", path, failure)
        }
    }
    // Configure the console's input prompter for scrollback and tab completion
    if c.prompter != nil {
        if content, err := ioutil.ReadFile(c.histPath); err != nil {
            c.prompter.SetHistory(nil)
        } else {
            c.history = strings.Split(string(content), "\n")
            c.prompter.SetHistory(c.history)
        }
        c.prompter.SetWordCompleter(c.AutoCompleteInput)
    }
    return nil
}

// consoleOutput is an override for the console.log and console.error methods to
// stream the output into the configured output stream instead of stdout.
func (c *Console) consoleOutput(call otto.FunctionCall) otto.Value {
    output := []string{}
    for _, argument := range call.ArgumentList {
        output = append(output, fmt.Sprintf("%v", argument))
    }
    fmt.Fprintln(c.printer, strings.Join(output, " "))
    return otto.Value{}
}

// AutoCompleteInput is a pre-assembled word completer to be used by the user
// input prompter to provide hints to the user about the methods available.
func (c *Console) AutoCompleteInput(line string, pos int) (string, []string, string) {
    // No completions can be provided for empty inputs
    if len(line) == 0 || pos == 0 {
        return "", nil, ""
    }
    // Chunck data to relevant part for autocompletion
    // E.g. in case of nested lines eth.getBalance(eth.coinb<tab><tab>
    start := 0
    for start = pos - 1; start > 0; start-- {
        // Skip all methods and namespaces (i.e. including te dot)
        if line[start] == '.' || (line[start] >= 'a' && line[start] <= 'z') || (line[start] >= 'A' && line[start] <= 'Z') {
            continue
        }
        // Handle web3 in a special way (i.e. other numbers aren't auto completed)
        if start >= 3 && line[start-3:start] == "web3" {
            start -= 3
            continue
        }
        // We've hit an unexpected character, autocomplete form here
        start++
        break
    }
    return line[:start], c.jsre.CompleteKeywords(line[start:pos]), line[pos:]
}

// Welcome show summary of current Geth instance and some metadata about the
// console's available modules.
func (c *Console) Welcome() {
    // Print some generic Geth metadata
    fmt.Fprintf(c.printer, "Welcome to the Geth JavaScript console!\n\n")
    c.jsre.Run(`
        console.log("instance: " + web3.version.node);
        console.log("coinbase: " + eth.coinbase);
        console.log("at block: " + eth.blockNumber + " (" + new Date(1000 * eth.getBlock(eth.blockNumber).timestamp) + ")");
        console.log(" datadir: " + admin.datadir);
    `)
    // List all the supported modules for the user to call
    if apis, err := c.client.SupportedModules(); err == nil {
        modules := make([]string, 0, len(apis))
        for api, version := range apis {
            modules = append(modules, fmt.Sprintf("%s:%s", api, version))
        }
        sort.Strings(modules)
        fmt.Fprintln(c.printer, " modules:", strings.Join(modules, " "))
    }
    fmt.Fprintln(c.printer)
}

// Evaluate executes code and pretty prints the result to the specified output
// stream.
func (c *Console) Evaluate(statement string) error {
    defer func() {
        if r := recover(); r != nil {
            fmt.Fprintf(c.printer, "[native] error: %v\n", r)
        }
    }()
    if err := c.jsre.Evaluate(statement, c.printer); err != nil {
        return err
    }
    return nil
}

// Interactive starts an interactive user session, where input is propted from
// the configured user prompter.
func (c *Console) Interactive() {
    var (
        prompt    = c.prompt          // Current prompt line (used for multi-line inputs)
        indents   = 0                 // Current number of input indents (used for multi-line inputs)
        input     = ""                // Current user input
        scheduler = make(chan string) // Channel to send the next prompt on and receive the input
    )
    // Start a goroutine to listen for promt requests and send back inputs
    go func() {
        for {
            // Read the next user input
            line, err := c.prompter.PromptInput(<-scheduler)
            if err != nil {
                // In case of an error, either clear the prompt or fail
                if err == liner.ErrPromptAborted { // ctrl-C
                    prompt, indents, input = c.prompt, 0, ""
                    scheduler <- ""
                    continue
                }
                close(scheduler)
                return
            }
            // User input retrieved, send for interpretation and loop
            scheduler <- line
        }
    }()
    // Monitor Ctrl-C too in case the input is empty and we need to bail
    abort := make(chan os.Signal, 1)
    signal.Notify(abort, os.Interrupt)

    // Start sending prompts to the user and reading back inputs
    for {
        // Send the next prompt, triggering an input read and process the result
        scheduler <- prompt
        select {
        case <-abort:
            // User forcefully quite the console
            fmt.Fprintln(c.printer, "caught interrupt, exiting")
            return

        case line, ok := <-scheduler:
            // User input was returned by the prompter, handle special cases
            if !ok || (indents <= 0 && exit.MatchString(line)) {
                return
            }
            if onlyWhitespace.MatchString(line) {
                continue
            }
            // Append the line to the input and check for multi-line interpretation
            input += line + "\n"

            indents = strings.Count(input, "{") + strings.Count(input, "(") - strings.Count(input, "}") - strings.Count(input, ")")
            if indents <= 0 {
                prompt = c.prompt
            } else {
                prompt = strings.Repeat("..", indents*2) + " "
            }
            // If all the needed lines are present, save the command and run
            if indents <= 0 {
                if len(input) > 0 && input[0] != ' ' && !passwordRegexp.MatchString(input) {
                    if command := strings.TrimSpace(input); len(c.history) == 0 || command != c.history[len(c.history)-1] {
                        c.history = append(c.history, command)
                        if c.prompter != nil {
                            c.prompter.AppendHistory(command)
                        }
                    }
                }
                c.Evaluate(input)
                input = ""
            }
        }
    }
}

// Execute runs the JavaScript file specified as the argument.
func (c *Console) Execute(path string) error {
    return c.jsre.Exec(path)
}

// Stop cleans up the console and terminates the runtime envorinment.
func (c *Console) Stop(graceful bool) error {
    if err := ioutil.WriteFile(c.histPath, []byte(strings.Join(c.history, "\n")), 0600); err != nil {
        return err
    }
    if err := os.Chmod(c.histPath, 0600); err != nil { // Force 0600, even if it was different previously
        return err
    }
    c.jsre.Stop(graceful)
    return nil
}