1 files changed, 175 insertions, 0 deletions
diff --git a/rpc/websocket.go b/rpc/websocket.go
new file mode 100644
index 0000000..d87e8a5
--- /dev/null
+++ b/rpc/websocket.go
@@ -0,0 +1,175 @@
+// 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 (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"sync"
+
+	mapset "github.com/deckarep/golang-set"
+	"github.com/ava-labs/go-ethereum/log"
+	"github.com/gorilla/websocket"
+)
+
+const (
+	wsReadBuffer  = 1024
+	wsWriteBuffer = 1024
+)
+
+var wsBufferPool = new(sync.Pool)
+
+// NewWSServer creates a new websocket RPC server around an API provider.
+//
+// Deprecated: use Server.WebsocketHandler
+func NewWSServer(allowedOrigins []string, srv *Server) *http.Server {
+	return &http.Server{Handler: srv.WebsocketHandler(allowedOrigins)}
+}
+
+// WebsocketHandler returns a handler that serves JSON-RPC to WebSocket connections.
+//
+// allowedOrigins should be a comma-separated list of allowed origin URLs.
+// To allow connections with any origin, pass "*".
+func (s *Server) WebsocketHandler(allowedOrigins []string) http.Handler {
+	var upgrader = websocket.Upgrader{
+		ReadBufferSize:  wsReadBuffer,
+		WriteBufferSize: wsWriteBuffer,
+		WriteBufferPool: wsBufferPool,
+		CheckOrigin:     wsHandshakeValidator(allowedOrigins),
+	}
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		conn, err := upgrader.Upgrade(w, r, nil)
+		if err != nil {
+			log.Debug("WebSocket upgrade failed", "err", err)
+			return
+		}
+		codec := newWebsocketCodec(conn)
+		s.ServeCodec(codec, OptionMethodInvocation|OptionSubscriptions)
+	})
+}
+
+// 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(*http.Request) bool {
+	origins := mapset.NewSet()
+	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.ToSlice()) == 0 {
+		origins.Add("http://localhost")
+		if hostname, err := os.Hostname(); err == nil {
+			origins.Add("http://" + strings.ToLower(hostname))
+		}
+	}
+	log.Debug(fmt.Sprintf("Allowed origin(s) for WS RPC interface %v", origins.ToSlice()))
+
+	f := func(req *http.Request) bool {
+		// Skip origin verification if no Origin header is present. The origin check
+		// is supposed to protect against browser based attacks. Browsers always set
+		// Origin. Non-browser software can put anything in origin and checking it doesn't
+		// provide additional security.
+		if _, ok := req.Header["Origin"]; !ok {
+			return true
+		}
+		// Verify origin against whitelist.
+		origin := strings.ToLower(req.Header.Get("Origin"))
+		if allowAllOrigins || origins.Contains(origin) {
+			return true
+		}
+		log.Warn("Rejected WebSocket connection", "origin", origin)
+		return false
+	}
+
+	return f
+}
+
+type wsHandshakeError struct {
+	err    error
+	status string
+}
+
+func (e wsHandshakeError) Error() string {
+	s := e.err.Error()
+	if e.status != "" {
+		s += " (HTTP status " + e.status + ")"
+	}
+	return s
+}
+
+// DialWebsocket creates a new RPC client that communicates with a JSON-RPC server
+// that is listening on the given endpoint.
+//
+// The context is used for the initial connection establishment. It does not
+// affect subsequent interactions with the client.
+func DialWebsocket(ctx context.Context, endpoint, origin string) (*Client, error) {
+	endpoint, header, err := wsClientHeaders(endpoint, origin)
+	if err != nil {
+		return nil, err
+	}
+	dialer := websocket.Dialer{
+		ReadBufferSize:  wsReadBuffer,
+		WriteBufferSize: wsWriteBuffer,
+		WriteBufferPool: wsBufferPool,
+	}
+	return newClient(ctx, func(ctx context.Context) (ServerCodec, error) {
+		conn, resp, err := dialer.DialContext(ctx, endpoint, header)
+		if err != nil {
+			hErr := wsHandshakeError{err: err}
+			if resp != nil {
+				hErr.status = resp.Status
+			}
+			return nil, hErr
+		}
+		return newWebsocketCodec(conn), nil
+	})
+}
+
+func wsClientHeaders(endpoint, origin string) (string, http.Header, error) {
+	endpointURL, err := url.Parse(endpoint)
+	if err != nil {
+		return endpoint, nil, err
+	}
+	header := make(http.Header)
+	if origin != "" {
+		header.Add("origin", origin)
+	}
+	if endpointURL.User != nil {
+		b64auth := base64.StdEncoding.EncodeToString([]byte(endpointURL.User.String()))
+		header.Add("authorization", "Basic "+b64auth)
+		endpointURL.User = nil
+	}
+	return endpointURL.String(), header, nil
+}
+
+func newWebsocketCodec(conn *websocket.Conn) ServerCodec {
+	conn.SetReadLimit(maxRequestContentLength)
+	return newCodec(conn, conn.WriteJSON, conn.ReadJSON)
+}