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// 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 rpc
import (
"fmt"
"net/http"
"os"
"strings"
"sync"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"golang.org/x/net/websocket"
"gopkg.in/fatih/set.v0"
)
// wsReaderWriterCloser reads and write payloads from and to a websocket connection.
type wsReaderWriterCloser struct {
c *websocket.Conn
}
// Read will read incoming payload data into p.
func (rw *wsReaderWriterCloser) Read(p []byte) (int, error) {
return rw.c.Read(p)
}
// Write writes p to the websocket.
func (rw *wsReaderWriterCloser) Write(p []byte) (int, error) {
return rw.c.Write(p)
}
// Close closes the websocket connection.
func (rw *wsReaderWriterCloser) Close() error {
return rw.c.Close()
}
// wsHandshakeValidator returns a handler that verifies the origin during the
// websocket upgrade process. When a '*' is specified as an allowed origins all
// connections are accepted.
func wsHandshakeValidator(allowedOrigins []string) func(*websocket.Config, *http.Request) error {
origins := set.New()
allowAllOrigins := false
for _, origin := range allowedOrigins {
if origin == "*" {
allowAllOrigins = true
}
if origin != "" {
origins.Add(strings.ToLower(origin))
}
}
// allow localhost if no allowedOrigins are specified.
if len(origins.List()) == 0 {
origins.Add("http://localhost")
if hostname, err := os.Hostname(); err == nil {
origins.Add("http://" + strings.ToLower(hostname))
}
}
glog.V(logger.Debug).Infof("Allowed origin(s) for WS RPC interface %v\n", origins.List())
f := func(cfg *websocket.Config, req *http.Request) error {
origin := strings.ToLower(req.Header.Get("Origin"))
if allowAllOrigins || origins.Has(origin) {
return nil
}
glog.V(logger.Debug).Infof("origin '%s' not allowed on WS-RPC interface\n", origin)
return fmt.Errorf("origin %s not allowed", origin)
}
return f
}
// NewWSServer creates a new websocket RPC server around an API provider.
func NewWSServer(allowedOrigins string, handler *Server) *http.Server {
return &http.Server{
Handler: websocket.Server{
Handshake: wsHandshakeValidator(strings.Split(allowedOrigins, ",")),
Handler: func(conn *websocket.Conn) {
handler.ServeCodec(NewJSONCodec(&wsReaderWriterCloser{conn}),
OptionMethodInvocation|OptionSubscriptions)
},
},
}
}
// wsClient represents a RPC client that communicates over websockets with a
// RPC server.
type wsClient struct {
endpoint string
connMu sync.Mutex
conn *websocket.Conn
}
// NewWSClientj creates a new RPC client that communicates with a RPC server
// that is listening on the given endpoint using JSON encoding.
func NewWSClient(endpoint string) (Client, error) {
return &wsClient{endpoint: endpoint}, nil
}
// connection will return a websocket connection to the RPC server. It will
// (re)connect when necessary.
func (client *wsClient) connection() (*websocket.Conn, error) {
if client.conn != nil {
return client.conn, nil
}
origin, err := os.Hostname()
if err != nil {
return nil, err
}
origin = "http://" + origin
client.conn, err = websocket.Dial(client.endpoint, "", origin)
return client.conn, err
}
// SupportedModules is the collection of modules the RPC server offers.
func (client *wsClient) SupportedModules() (map[string]string, error) {
return SupportedModules(client)
}
// Send writes the JSON serialized msg to the websocket. It will create a new
// websocket connection to the server if the client is currently not connected.
func (client *wsClient) Send(msg interface{}) (err error) {
client.connMu.Lock()
defer client.connMu.Unlock()
var conn *websocket.Conn
if conn, err = client.connection(); err == nil {
if err = websocket.JSON.Send(conn, msg); err != nil {
client.conn.Close()
client.conn = nil
}
}
return err
}
// Recv reads a JSON message from the websocket and unmarshals it into msg.
func (client *wsClient) Recv(msg interface{}) (err error) {
client.connMu.Lock()
defer client.connMu.Unlock()
var conn *websocket.Conn
if conn, err = client.connection(); err == nil {
if err = websocket.JSON.Receive(conn, msg); err != nil {
client.conn.Close()
client.conn = nil
}
}
return
}
// Close closes the underlaying websocket connection.
func (client *wsClient) Close() {
client.connMu.Lock()
defer client.connMu.Unlock()
if client.conn != nil {
client.conn.Close()
client.conn = nil
}
}
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