path: root/console/bridge.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 (
    "encoding/json"
    "fmt"
    "io"
    "time"

    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/rpc"
    "github.com/robertkrimen/otto"
)

// bridge is a collection of JavaScript utility methods to bride the .js runtime
// environment and the Go RPC connection backing the remote method calls.
type bridge struct {
    client   rpc.Client   // RPC client to execute Ethereum requests through
    prompter UserPrompter // Input prompter to allow interactive user feedback
    printer  io.Writer    // Output writer to serialize any display strings to
}

// newBridge creates a new JavaScript wrapper around an RPC client.
func newBridge(client rpc.Client, prompter UserPrompter, printer io.Writer) *bridge {
    return &bridge{
        client:   client,
        prompter: prompter,
        printer:  printer,
    }
}

// NewAccount is a wrapper around the personal.newAccount RPC method that uses a
// non-echoing password prompt to aquire the passphrase and executes the original
// RPC method (saved in jeth.newAccount) with it to actually execute the RPC call.
func (b *bridge) NewAccount(call otto.FunctionCall) (response otto.Value) {
    var (
        password string
        confirm  string
        err      error
    )
    switch {
    // No password was specified, prompt the user for it
    case len(call.ArgumentList) == 0:
        if password, err = b.prompter.PromptPassword("Passphrase: "); err != nil {
            throwJSException(err.Error())
        }
        if confirm, err = b.prompter.PromptPassword("Repeat passphrase: "); err != nil {
            throwJSException(err.Error())
        }
        if password != confirm {
            throwJSException("passphrases don't match!")
        }

    // A single string password was specified, use that
    case len(call.ArgumentList) == 1 && call.Argument(0).IsString():
        password, _ = call.Argument(0).ToString()

    // Otherwise fail with some error
    default:
        throwJSException("expected 0 or 1 string argument")
    }
    // Password aquired, execute the call and return
    ret, err := call.Otto.Call("jeth.newAccount", nil, password)
    if err != nil {
        throwJSException(err.Error())
    }
    return ret
}

// UnlockAccount is a wrapper around the personal.unlockAccount RPC method that
// uses a non-echoing password prompt to aquire the passphrase and executes the
// original RPC method (saved in jeth.unlockAccount) with it to actually execute
// the RPC call.
func (b *bridge) UnlockAccount(call otto.FunctionCall) (response otto.Value) {
    // Make sure we have an account specified to unlock
    if !call.Argument(0).IsString() {
        throwJSException("first argument must be the account to unlock")
    }
    account := call.Argument(0)

    // If password is not given or is the null value, prompt the user for it
    var passwd otto.Value

    if call.Argument(1).IsUndefined() || call.Argument(1).IsNull() {
        fmt.Fprintf(b.printer, "Unlock account %s\n", account)
        if input, err := b.prompter.PromptPassword("Passphrase: "); err != nil {
            throwJSException(err.Error())
        } else {
            passwd, _ = otto.ToValue(input)
        }
    } else {
        if !call.Argument(1).IsString() {
            throwJSException("password must be a string")
        }
        passwd = call.Argument(1)
    }
    // Third argument is the duration how long the account must be unlocked.
    duration := otto.NullValue()
    if call.Argument(2).IsDefined() && !call.Argument(2).IsNull() {
        if !call.Argument(2).IsNumber() {
            throwJSException("unlock duration must be a number")
        }
        duration = call.Argument(2)
    }
    // Send the request to the backend and return
    val, err := call.Otto.Call("jeth.unlockAccount", nil, account, passwd, duration)
    if err != nil {
        throwJSException(err.Error())
    }
    return val
}

// Sleep will block the console for the specified number of seconds.
func (b *bridge) Sleep(call otto.FunctionCall) (response otto.Value) {
    if call.Argument(0).IsNumber() {
        sleep, _ := call.Argument(0).ToInteger()
        time.Sleep(time.Duration(sleep) * time.Second)
        return otto.TrueValue()
    }
    return throwJSException("usage: sleep(<number of seconds>)")
}

// SleepBlocks will block the console for a specified number of new blocks optionally
// until the given timeout is reached.
func (b *bridge) SleepBlocks(call otto.FunctionCall) (response otto.Value) {
    var (
        blocks = int64(0)
        sleep  = int64(9999999999999999) // indefinitely
    )
    // Parse the input parameters for the sleep
    nArgs := len(call.ArgumentList)
    if nArgs == 0 {
        throwJSException("usage: sleepBlocks(<n blocks>[, max sleep in seconds])")
    }
    if nArgs >= 1 {
        if call.Argument(0).IsNumber() {
            blocks, _ = call.Argument(0).ToInteger()
        } else {
            throwJSException("expected number as first argument")
        }
    }
    if nArgs >= 2 {
        if call.Argument(1).IsNumber() {
            sleep, _ = call.Argument(1).ToInteger()
        } else {
            throwJSException("expected number as second argument")
        }
    }
    // go through the console, this will allow web3 to call the appropriate
    // callbacks if a delayed response or notification is received.
    blockNumber := func() int64 {
        result, err := call.Otto.Run("eth.blockNumber")
        if err != nil {
            throwJSException(err.Error())
        }
        block, err := result.ToInteger()
        if err != nil {
            throwJSException(err.Error())
        }
        return block
    }
    // Poll the current block number until either it ot a timeout is reached
    targetBlockNr := blockNumber() + blocks
    deadline := time.Now().Add(time.Duration(sleep) * time.Second)

    for time.Now().Before(deadline) {
        if blockNumber() >= targetBlockNr {
            return otto.TrueValue()
        }
        time.Sleep(time.Second)
    }
    return otto.FalseValue()
}

// Send will serialize the first argument, send it to the node and returns the response.
func (b *bridge) Send(call otto.FunctionCall) (response otto.Value) {
    // Ensure that we've got a batch request (array) or a single request (object)
    arg := call.Argument(0).Object()
    if arg == nil || (arg.Class() != "Array" && arg.Class() != "Object") {
        throwJSException("request must be an object or array")
    }
    // Convert the otto VM arguments to Go values
    data, err := call.Otto.Call("JSON.stringify", nil, arg)
    if err != nil {
        throwJSException(err.Error())
    }
    reqjson, err := data.ToString()
    if err != nil {
        throwJSException(err.Error())
    }

    var (
        reqs  []rpc.JSONRequest
        batch = true
    )
    if err = json.Unmarshal([]byte(reqjson), &reqs); err != nil {
        // single request?
        reqs = make([]rpc.JSONRequest, 1)
        if err = json.Unmarshal([]byte(reqjson), &reqs[0]); err != nil {
            throwJSException("invalid request")
        }
        batch = false
    }
    // Iteratively execute the requests
    call.Otto.Set("response_len", len(reqs))
    call.Otto.Run("var ret_response = new Array(response_len);")

    for i, req := range reqs {
        // Execute the RPC request and parse the reply
        if err = b.client.Send(&req); err != nil {
            return newErrorResponse(call, -32603, err.Error(), req.Id)
        }
        result := make(map[string]interface{})
        if err = b.client.Recv(&result); err != nil {
            return newErrorResponse(call, -32603, err.Error(), req.Id)
        }
        // Feed the reply back into the JavaScript runtime environment
        id, _ := result["id"]
        jsonver, _ := result["jsonrpc"]

        call.Otto.Set("ret_id", id)
        call.Otto.Set("ret_jsonrpc", jsonver)
        call.Otto.Set("response_idx", i)

        if res, ok := result["result"]; ok {
            payload, _ := json.Marshal(res)
            call.Otto.Set("ret_result", string(payload))
            response, err = call.Otto.Run(`
                ret_response[response_idx] = { jsonrpc: ret_jsonrpc, id: ret_id, result: JSON.parse(ret_result) };
            `)
            continue
        }
        if res, ok := result["error"]; ok {
            payload, _ := json.Marshal(res)
            call.Otto.Set("ret_result", string(payload))
            response, err = call.Otto.Run(`
                ret_response[response_idx] = { jsonrpc: ret_jsonrpc, id: ret_id, error: JSON.parse(ret_result) };
            `)
            continue
        }
        return newErrorResponse(call, -32603, fmt.Sprintf("Invalid response"), new(int64))
    }
    // Convert single requests back from batch ones
    if !batch {
        call.Otto.Run("ret_response = ret_response[0];")
    }
    // Execute any registered callbacks
    if call.Argument(1).IsObject() {
        call.Otto.Set("callback", call.Argument(1))
        call.Otto.Run(`
        if (Object.prototype.toString.call(callback) == '[object Function]') {
            callback(null, ret_response);
        }
        `)
    }
    return
}

// throwJSException panics on an otto.Value. The Otto VM will recover from the
// Go panic and throw msg as a JavaScript error.
func throwJSException(msg interface{}) otto.Value {
    val, err := otto.ToValue(msg)
    if err != nil {
        glog.V(logger.Error).Infof("Failed to serialize JavaScript exception %v: %v", msg, err)
    }
    panic(val)
}

// newErrorResponse creates a JSON RPC error response for a specific request id,
// containing the specified error code and error message. Beside returning the
// error to the caller, it also sets the ret_error and ret_response JavaScript
// variables.
func newErrorResponse(call otto.FunctionCall, code int, msg string, id interface{}) (response otto.Value) {
    // Bundle the error into a JSON RPC call response
    res := rpc.JSONErrResponse{
        Version: rpc.JSONRPCVersion,
        Id:      id,
        Error: rpc.JSONError{
            Code:    code,
            Message: msg,
        },
    }
    // Serialize the error response into JavaScript variables
    errObj, err := json.Marshal(res.Error)
    if err != nil {
        glog.V(logger.Error).Infof("Failed to serialize JSON RPC error: %v", err)
    }
    resObj, err := json.Marshal(res)
    if err != nil {
        glog.V(logger.Error).Infof("Failed to serialize JSON RPC error response: %v", err)
    }

    if _, err = call.Otto.Run("ret_error = " + string(errObj)); err != nil {
        glog.V(logger.Error).Infof("Failed to set `ret_error` to the occurred error: %v", err)
    }
    resVal, err := call.Otto.Run("ret_response = " + string(resObj))
    if err != nil {
        glog.V(logger.Error).Infof("Failed to set `ret_response` to the JSON RPC response: %v", err)
    }
    return resVal
}