path: root/rpc/comms/http.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 comms

import (
    "fmt"
    "net/http"
    "strings"

    "bytes"
    "io/ioutil"

    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/rpc/codec"
    "github.com/ethereum/go-ethereum/rpc/shared"
    "github.com/rs/cors"
)

var (
    // main HTTP rpc listener
    httpListener         *stoppableTCPListener
    listenerStoppedError = fmt.Errorf("Listener has stopped")
)

type HttpConfig struct {
    ListenAddress string
    ListenPort    uint
    CorsDomain    string
}

func StartHttp(cfg HttpConfig, codec codec.Codec, api shared.EthereumApi) error {
    if httpListener != nil {
        if fmt.Sprintf("%s:%d", cfg.ListenAddress, cfg.ListenPort) != httpListener.Addr().String() {
            return fmt.Errorf("RPC service already running on %s ", httpListener.Addr().String())
        }
        return nil // RPC service already running on given host/port
    }

    l, err := newStoppableTCPListener(fmt.Sprintf("%s:%d", cfg.ListenAddress, cfg.ListenPort))
    if err != nil {
        glog.V(logger.Error).Infof("Can't listen on %s:%d: %v", cfg.ListenAddress, cfg.ListenPort, err)
        return err
    }
    httpListener = l

    var handler http.Handler
    if len(cfg.CorsDomain) > 0 {
        var opts cors.Options
        opts.AllowedMethods = []string{"POST"}
        opts.AllowedOrigins = strings.Split(cfg.CorsDomain, " ")

        c := cors.New(opts)
        handler = newStoppableHandler(c.Handler(gethHttpHandler(codec, api)), l.stop)
    } else {
        handler = newStoppableHandler(gethHttpHandler(codec, api), l.stop)
    }

    go http.Serve(l, handler)

    return nil
}

func StopHttp() {
    if httpListener != nil {
        httpListener.Stop()
        httpListener = nil
    }
}

type httpClient struct {
    address string
    port    uint
    codec   codec.ApiCoder
    lastRes interface{}
    lastErr error
}

// Create a new in process client
func NewHttpClient(cfg HttpConfig, c codec.Codec) *httpClient {
    return &httpClient{
        address: cfg.ListenAddress,
        port:    cfg.ListenPort,
        codec:   c.New(nil),
    }
}

func (self *httpClient) Close() {
    // do nothing
}

func (self *httpClient) Send(req interface{}) error {
    var body []byte
    var err error

    self.lastRes = nil
    self.lastErr = nil

    if body, err = self.codec.Encode(req); err != nil {
        return err
    }

    httpReq, err := http.NewRequest("POST", fmt.Sprintf("%s:%d", self.address, self.port), bytes.NewBuffer(body))
    if err != nil {
        return err
    }
    httpReq.Header.Set("Content-Type", "application/json")

    client := http.Client{}
    resp, err := client.Do(httpReq)
    if err != nil {
        return err
    }

    defer resp.Body.Close()

    if resp.Status == "200 OK" {
        reply, _ := ioutil.ReadAll(resp.Body)
        var rpcSuccessResponse shared.SuccessResponse
        if err = self.codec.Decode(reply, &rpcSuccessResponse); err == nil {
            self.lastRes = rpcSuccessResponse.Result
            self.lastErr = err
            return nil
        } else {
            var rpcErrorResponse shared.ErrorResponse
            if err = self.codec.Decode(reply, &rpcErrorResponse); err == nil {
                self.lastRes = rpcErrorResponse.Error
                self.lastErr = err
                return nil
            } else {
                return err
            }
        }
    }

    return fmt.Errorf("Not implemented")
}

func (self *httpClient) Recv() (interface{}, error) {
    return self.lastRes, self.lastErr
}

func (self *httpClient) SupportedModules() (map[string]string, error) {
    var body []byte
    var err error

    payload := shared.Request{
        Id:      1,
        Jsonrpc: "2.0",
        Method:  "modules",
    }

    if body, err = self.codec.Encode(payload); err != nil {
        return nil, err
    }

    req, err := http.NewRequest("POST", fmt.Sprintf("%s:%d", self.address, self.port), bytes.NewBuffer(body))
    if err != nil {
        return nil, err
    }
    req.Header.Set("Content-Type", "application/json")

    client := http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        return nil, err
    }

    defer resp.Body.Close()

    if resp.Status == "200 OK" {
        reply, _ := ioutil.ReadAll(resp.Body)
        var rpcRes shared.SuccessResponse
        if err = self.codec.Decode(reply, &rpcRes); err != nil {
            return nil, err
        }

        result := make(map[string]string)
        if modules, ok := rpcRes.Result.(map[string]interface{}); ok {
            for a, v := range modules {
                result[a] = fmt.Sprintf("%s", v)
            }
            return result, nil
        }
        err = fmt.Errorf("Unable to parse module response - %v", rpcRes.Result)
    } else {
        fmt.Printf("resp.Status = %s\n", resp.Status)
        fmt.Printf("err = %v\n", err)
    }

    return nil, err
}