move from tendermint/tendermint

server/handlers.go

@@ -0,0 +1,553 @@
+package rpcserver
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"reflect"
+	"sort"
+	"time"
+
+	"github.com/gorilla/websocket"
+	. "github.com/tendermint/go-common"
+	"github.com/tendermint/go-events"
+	. "github.com/tendermint/go-rpc/types"
+	"github.com/tendermint/go-wire"
+)
+
+func RegisterRPCFuncs(mux *http.ServeMux, funcMap map[string]*RPCFunc) {
+	// HTTP endpoints
+	for funcName, rpcFunc := range funcMap {
+		mux.HandleFunc("/"+funcName, makeHTTPHandler(rpcFunc))
+	}
+
+	// JSONRPC endpoints
+	mux.HandleFunc("/", makeJSONRPCHandler(funcMap))
+}
+
+//-------------------------------------
+// function introspection
+
+// holds all type information for each function
+type RPCFunc struct {
+	f        reflect.Value  // underlying rpc function
+	args     []reflect.Type // type of each function arg
+	returns  []reflect.Type // type of each return arg
+	argNames []string       // name of each argument
+	ws       bool           // websocket only
+}
+
+// wraps a function for quicker introspection
+func NewRPCFunc(f interface{}, args []string) *RPCFunc {
+	return &RPCFunc{
+		f:        reflect.ValueOf(f),
+		args:     funcArgTypes(f),
+		returns:  funcReturnTypes(f),
+		argNames: args,
+		ws:       false,
+	}
+}
+
+func NewWSRPCFunc(f interface{}, args []string) *RPCFunc {
+	return &RPCFunc{
+		f:        reflect.ValueOf(f),
+		args:     funcArgTypes(f),
+		returns:  funcReturnTypes(f),
+		argNames: args,
+		ws:       true,
+	}
+}
+
+// return a function's argument types
+func funcArgTypes(f interface{}) []reflect.Type {
+	t := reflect.TypeOf(f)
+	n := t.NumIn()
+	typez := make([]reflect.Type, n)
+	for i := 0; i < n; i++ {
+		typez[i] = t.In(i)
+	}
+	return typez
+}
+
+// return a function's return types
+func funcReturnTypes(f interface{}) []reflect.Type {
+	t := reflect.TypeOf(f)
+	n := t.NumOut()
+	typez := make([]reflect.Type, n)
+	for i := 0; i < n; i++ {
+		typez[i] = t.Out(i)
+	}
+	return typez
+}
+
+// function introspection
+//-----------------------------------------------------------------------------
+// rpc.json
+
+// jsonrpc calls grab the given method's function info and runs reflect.Call
+func makeJSONRPCHandler(funcMap map[string]*RPCFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		b, _ := ioutil.ReadAll(r.Body)
+		// if its an empty request (like from a browser),
+		// just display a list of functions
+		if len(b) == 0 {
+			writeListOfEndpoints(w, r, funcMap)
+			return
+		}
+
+		var request RPCRequest
+		err := json.Unmarshal(b, &request)
+		if err != nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse("", nil, err.Error()))
+			return
+		}
+		if len(r.URL.Path) > 1 {
+			WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, nil, fmt.Sprintf("Invalid JSONRPC endpoint %s", r.URL.Path)))
+			return
+		}
+		rpcFunc := funcMap[request.Method]
+		if rpcFunc == nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, nil, "RPC method unknown: "+request.Method))
+			return
+		}
+		if rpcFunc.ws {
+			WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, nil, "RPC method is only for websockets: "+request.Method))
+			return
+		}
+		args, err := jsonParamsToArgs(rpcFunc, request.Params)
+		if err != nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, nil, err.Error()))
+			return
+		}
+		returns := rpcFunc.f.Call(args)
+		log.Info("HTTPJSONRPC", "method", request.Method, "args", args, "returns", returns)
+		result, err := unreflectResult(returns)
+		if err != nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, nil, err.Error()))
+			return
+		}
+		WriteRPCResponseHTTP(w, NewRPCResponse(request.ID, result, ""))
+	}
+}
+
+// Convert a list of interfaces to properly typed values
+func jsonParamsToArgs(rpcFunc *RPCFunc, params []interface{}) ([]reflect.Value, error) {
+	if len(rpcFunc.argNames) != len(params) {
+		return nil, errors.New(fmt.Sprintf("Expected %v parameters (%v), got %v (%v)",
+			len(rpcFunc.argNames), rpcFunc.argNames, len(params), params))
+	}
+	values := make([]reflect.Value, len(params))
+	for i, p := range params {
+		ty := rpcFunc.args[i]
+		v, err := _jsonObjectToArg(ty, p)
+		if err != nil {
+			return nil, err
+		}
+		values[i] = v
+	}
+	return values, nil
+}
+
+// Same as above, but with the first param the websocket connection
+func jsonParamsToArgsWS(rpcFunc *RPCFunc, params []interface{}, wsCtx WSRPCContext) ([]reflect.Value, error) {
+	if len(rpcFunc.argNames) != len(params) {
+		return nil, errors.New(fmt.Sprintf("Expected %v parameters (%v), got %v (%v)",
+			len(rpcFunc.argNames)-1, rpcFunc.argNames[1:], len(params), params))
+	}
+	values := make([]reflect.Value, len(params)+1)
+	values[0] = reflect.ValueOf(wsCtx)
+	for i, p := range params {
+		ty := rpcFunc.args[i+1]
+		v, err := _jsonObjectToArg(ty, p)
+		if err != nil {
+			return nil, err
+		}
+		values[i+1] = v
+	}
+	return values, nil
+}
+
+func _jsonObjectToArg(ty reflect.Type, object interface{}) (reflect.Value, error) {
+	var err error
+	v := reflect.New(ty)
+	wire.ReadJSONObjectPtr(v.Interface(), object, &err)
+	if err != nil {
+		return v, err
+	}
+	v = v.Elem()
+	return v, nil
+}
+
+// rpc.json
+//-----------------------------------------------------------------------------
+// rpc.http
+
+// convert from a function name to the http handler
+func makeHTTPHandler(rpcFunc *RPCFunc) func(http.ResponseWriter, *http.Request) {
+	// Exception for websocket endpoints
+	if rpcFunc.ws {
+		return func(w http.ResponseWriter, r *http.Request) {
+			WriteRPCResponseHTTP(w, NewRPCResponse("", nil, "This RPC method is only for websockets"))
+		}
+	}
+	// All other endpoints
+	return func(w http.ResponseWriter, r *http.Request) {
+		args, err := httpParamsToArgs(rpcFunc, r)
+		if err != nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse("", nil, err.Error()))
+			return
+		}
+		returns := rpcFunc.f.Call(args)
+		log.Info("HTTPRestRPC", "method", r.URL.Path, "args", args, "returns", returns)
+		result, err := unreflectResult(returns)
+		if err != nil {
+			WriteRPCResponseHTTP(w, NewRPCResponse("", nil, err.Error()))
+			return
+		}
+		WriteRPCResponseHTTP(w, NewRPCResponse("", result, ""))
+	}
+}
+
+// Covert an http query to a list of properly typed values.
+// To be properly decoded the arg must be a concrete type from tendermint (if its an interface).
+func httpParamsToArgs(rpcFunc *RPCFunc, r *http.Request) ([]reflect.Value, error) {
+	argTypes := rpcFunc.args
+	argNames := rpcFunc.argNames
+
+	var err error
+	values := make([]reflect.Value, len(argNames))
+	for i, name := range argNames {
+		ty := argTypes[i]
+		arg := GetParam(r, name)
+		values[i], err = _jsonStringToArg(ty, arg)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return values, nil
+}
+
+func _jsonStringToArg(ty reflect.Type, arg string) (reflect.Value, error) {
+	var err error
+	v := reflect.New(ty)
+	wire.ReadJSONPtr(v.Interface(), []byte(arg), &err)
+	if err != nil {
+		return v, err
+	}
+	v = v.Elem()
+	return v, nil
+}
+
+// rpc.http
+//-----------------------------------------------------------------------------
+// rpc.websocket
+
+const (
+	writeChanCapacity     = 1000
+	wsWriteTimeoutSeconds = 30 // each write times out after this
+	wsReadTimeoutSeconds  = 30 // connection times out if we haven't received *anything* in this long, not even pings.
+	wsPingTickerSeconds   = 10 // send a ping every PingTickerSeconds.
+)
+
+// a single websocket connection
+// contains listener id, underlying ws connection,
+// and the event switch for subscribing to events
+type wsConnection struct {
+	QuitService
+
+	remoteAddr  string
+	baseConn    *websocket.Conn
+	writeChan   chan RPCResponse
+	readTimeout *time.Timer
+	pingTicker  *time.Ticker
+
+	funcMap map[string]*RPCFunc
+	evsw    *events.EventSwitch
+}
+
+// new websocket connection wrapper
+func NewWSConnection(baseConn *websocket.Conn, funcMap map[string]*RPCFunc, evsw *events.EventSwitch) *wsConnection {
+	wsc := &wsConnection{
+		remoteAddr: baseConn.RemoteAddr().String(),
+		baseConn:   baseConn,
+		writeChan:  make(chan RPCResponse, writeChanCapacity), // error when full.
+		funcMap:    funcMap,
+		evsw:       evsw,
+	}
+	wsc.QuitService = *NewQuitService(log, "wsConnection", wsc)
+	return wsc
+}
+
+// wsc.Start() blocks until the connection closes.
+func (wsc *wsConnection) OnStart() error {
+	wsc.QuitService.OnStart()
+
+	// Read subscriptions/unsubscriptions to events
+	go wsc.readRoutine()
+
+	// Custom Ping handler to touch readTimeout
+	wsc.readTimeout = time.NewTimer(time.Second * wsReadTimeoutSeconds)
+	wsc.pingTicker = time.NewTicker(time.Second * wsPingTickerSeconds)
+	wsc.baseConn.SetPingHandler(func(m string) error {
+		// NOTE: https://github.com/gorilla/websocket/issues/97
+		go wsc.baseConn.WriteControl(websocket.PongMessage, []byte(m), time.Now().Add(time.Second*wsWriteTimeoutSeconds))
+		wsc.readTimeout.Reset(time.Second * wsReadTimeoutSeconds)
+		return nil
+	})
+	wsc.baseConn.SetPongHandler(func(m string) error {
+		// NOTE: https://github.com/gorilla/websocket/issues/97
+		wsc.readTimeout.Reset(time.Second * wsReadTimeoutSeconds)
+		return nil
+	})
+	go wsc.readTimeoutRoutine()
+
+	// Write responses, BLOCKING.
+	wsc.writeRoutine()
+	return nil
+}
+
+func (wsc *wsConnection) OnStop() {
+	wsc.QuitService.OnStop()
+	wsc.evsw.RemoveListener(wsc.remoteAddr)
+	wsc.readTimeout.Stop()
+	wsc.pingTicker.Stop()
+	// The write loop closes the websocket connection
+	// when it exits its loop, and the read loop
+	// closes the writeChan
+}
+
+func (wsc *wsConnection) readTimeoutRoutine() {
+	select {
+	case <-wsc.readTimeout.C:
+		log.Notice("Stopping connection due to read timeout")
+		wsc.Stop()
+	case <-wsc.Quit:
+		return
+	}
+}
+
+// Implements WSRPCConnection
+func (wsc *wsConnection) GetRemoteAddr() string {
+	return wsc.remoteAddr
+}
+
+// Implements WSRPCConnection
+func (wsc *wsConnection) GetEventSwitch() *events.EventSwitch {
+	return wsc.evsw
+}
+
+// Implements WSRPCConnection
+// Blocking write to writeChan until service stops.
+func (wsc *wsConnection) WriteRPCResponse(resp RPCResponse) {
+	select {
+	case <-wsc.Quit:
+		return
+	case wsc.writeChan <- resp:
+	}
+}
+
+// Implements WSRPCConnection
+// Nonblocking write.
+func (wsc *wsConnection) TryWriteRPCResponse(resp RPCResponse) bool {
+	select {
+	case <-wsc.Quit:
+		return false
+	case wsc.writeChan <- resp:
+		return true
+	default:
+		return false
+	}
+}
+
+// Read from the socket and subscribe to or unsubscribe from events
+func (wsc *wsConnection) readRoutine() {
+	// Do not close writeChan, to allow WriteRPCResponse() to fail.
+	// defer close(wsc.writeChan)
+
+	for {
+		select {
+		case <-wsc.Quit:
+			return
+		default:
+			var in []byte
+			// Do not set a deadline here like below:
+			// wsc.baseConn.SetReadDeadline(time.Now().Add(time.Second * wsReadTimeoutSeconds))
+			// The client may not send anything for a while.
+			// We use `readTimeout` to handle read timeouts.
+			_, in, err := wsc.baseConn.ReadMessage()
+			if err != nil {
+				log.Notice("Failed to read from connection", "remote", wsc.remoteAddr)
+				// an error reading the connection,
+				// kill the connection
+				wsc.Stop()
+				return
+			}
+			var request RPCRequest
+			err = json.Unmarshal(in, &request)
+			if err != nil {
+				errStr := fmt.Sprintf("Error unmarshaling data: %s", err.Error())
+				wsc.WriteRPCResponse(NewRPCResponse(request.ID, nil, errStr))
+				continue
+			}
+
+			// Now, fetch the RPCFunc and execute it.
+
+			rpcFunc := wsc.funcMap[request.Method]
+			if rpcFunc == nil {
+				wsc.WriteRPCResponse(NewRPCResponse(request.ID, nil, "RPC method unknown: "+request.Method))
+				continue
+			}
+			var args []reflect.Value
+			if rpcFunc.ws {
+				wsCtx := WSRPCContext{Request: request, WSRPCConnection: wsc}
+				args, err = jsonParamsToArgsWS(rpcFunc, request.Params, wsCtx)
+			} else {
+				args, err = jsonParamsToArgs(rpcFunc, request.Params)
+			}
+			if err != nil {
+				wsc.WriteRPCResponse(NewRPCResponse(request.ID, nil, err.Error()))
+				continue
+			}
+			returns := rpcFunc.f.Call(args)
+			log.Info("WSJSONRPC", "method", request.Method, "args", args, "returns", returns)
+			result, err := unreflectResult(returns)
+			if err != nil {
+				wsc.WriteRPCResponse(NewRPCResponse(request.ID, nil, err.Error()))
+				continue
+			} else {
+				wsc.WriteRPCResponse(NewRPCResponse(request.ID, result, ""))
+				continue
+			}
+
+		}
+	}
+}
+
+// receives on a write channel and writes out on the socket
+func (wsc *wsConnection) writeRoutine() {
+	defer wsc.baseConn.Close()
+	var n, err = int(0), error(nil)
+	for {
+		select {
+		case <-wsc.Quit:
+			return
+		case <-wsc.pingTicker.C:
+			err := wsc.baseConn.WriteMessage(websocket.PingMessage, []byte{})
+			if err != nil {
+				log.Error("Failed to write ping message on websocket", "error", err)
+				wsc.Stop()
+				return
+			}
+		case msg := <-wsc.writeChan:
+			buf := new(bytes.Buffer)
+			wire.WriteJSON(msg, buf, &n, &err)
+			if err != nil {
+				log.Error("Failed to marshal RPCResponse to JSON", "error", err)
+			} else {
+				wsc.baseConn.SetWriteDeadline(time.Now().Add(time.Second * wsWriteTimeoutSeconds))
+				bufBytes := buf.Bytes()
+				if err = wsc.baseConn.WriteMessage(websocket.TextMessage, bufBytes); err != nil {
+					log.Warn("Failed to write response on websocket", "error", err)
+					wsc.Stop()
+					return
+				}
+			}
+		}
+	}
+}
+
+//----------------------------------------
+
+// Main manager for all websocket connections
+// Holds the event switch
+// NOTE: The websocket path is defined externally, e.g. in node/node.go
+type WebsocketManager struct {
+	websocket.Upgrader
+	funcMap map[string]*RPCFunc
+	evsw    *events.EventSwitch
+}
+
+func NewWebsocketManager(funcMap map[string]*RPCFunc, evsw *events.EventSwitch) *WebsocketManager {
+	return &WebsocketManager{
+		funcMap: funcMap,
+		evsw:    evsw,
+		Upgrader: websocket.Upgrader{
+			ReadBufferSize:  1024,
+			WriteBufferSize: 1024,
+			CheckOrigin: func(r *http.Request) bool {
+				// TODO
+				return true
+			},
+		},
+	}
+}
+
+// Upgrade the request/response (via http.Hijack) and starts the wsConnection.
+func (wm *WebsocketManager) WebsocketHandler(w http.ResponseWriter, r *http.Request) {
+	wsConn, err := wm.Upgrade(w, r, nil)
+	if err != nil {
+		// TODO - return http error
+		log.Error("Failed to upgrade to websocket connection", "error", err)
+		return
+	}
+
+	// register connection
+	con := NewWSConnection(wsConn, wm.funcMap, wm.evsw)
+	log.Notice("New websocket connection", "remote", con.remoteAddr)
+	con.Start() // Blocking
+}
+
+// rpc.websocket
+//-----------------------------------------------------------------------------
+
+// returns is result struct and error. If error is not nil, return it
+func unreflectResult(returns []reflect.Value) (interface{}, error) {
+	errV := returns[1]
+	if errV.Interface() != nil {
+		return nil, fmt.Errorf("%v", errV.Interface())
+	}
+	return returns[0].Interface(), nil
+}
+
+// writes a list of available rpc endpoints as an html page
+func writeListOfEndpoints(w http.ResponseWriter, r *http.Request, funcMap map[string]*RPCFunc) {
+	noArgNames := []string{}
+	argNames := []string{}
+	for name, funcData := range funcMap {
+		if len(funcData.args) == 0 {
+			noArgNames = append(noArgNames, name)
+		} else {
+			argNames = append(argNames, name)
+		}
+	}
+	sort.Strings(noArgNames)
+	sort.Strings(argNames)
+	buf := new(bytes.Buffer)
+	buf.WriteString("<html><body>")
+	buf.WriteString("<br>Available endpoints:<br>")
+
+	for _, name := range noArgNames {
+		link := fmt.Sprintf("http://%s/%s", r.Host, name)
+		buf.WriteString(fmt.Sprintf("<a href=\"%s\">%s</a></br>", link, link))
+	}
+
+	buf.WriteString("<br>Endpoints that require arguments:<br>")
+	for _, name := range argNames {
+		link := fmt.Sprintf("http://%s/%s?", r.Host, name)
+		funcData := funcMap[name]
+		for i, argName := range funcData.argNames {
+			link += argName + "=_"
+			if i < len(funcData.argNames)-1 {
+				link += "&"
+			}
+		}
+		buf.WriteString(fmt.Sprintf("<a href=\"%s\">%s</a></br>", link, link))
+	}
+	buf.WriteString("</body></html>")
+	w.Header().Set("Content-Type", "text/html")
+	w.WriteHeader(200)
+	w.Write(buf.Bytes())
+}

server/http_params.go

@@ -0,0 +1,89 @@
+package rpcserver
+
+import (
+	"encoding/hex"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strconv"
+)
+
+var (
+	// Parts of regular expressions
+	atom    = "[A-Z0-9!#$%&'*+\\-/=?^_`{|}~]+"
+	dotAtom = atom + `(?:\.` + atom + `)*`
+	domain  = `[A-Z0-9.-]+\.[A-Z]{2,4}`
+
+	RE_HEX     = regexp.MustCompile(`^(?i)[a-f0-9]+$`)
+	RE_EMAIL   = regexp.MustCompile(`^(?i)(` + dotAtom + `)@(` + dotAtom + `)$`)
+	RE_ADDRESS = regexp.MustCompile(`^(?i)[a-z0-9]{25,34}$`)
+	RE_HOST    = regexp.MustCompile(`^(?i)(` + domain + `)$`)
+
+	//RE_ID12       = regexp.MustCompile(`^[a-zA-Z0-9]{12}$`)
+)
+
+func GetParam(r *http.Request, param string) string {
+	s := r.URL.Query().Get(param)
+	if s == "" {
+		s = r.FormValue(param)
+	}
+	return s
+}
+
+func GetParamByteSlice(r *http.Request, param string) ([]byte, error) {
+	s := GetParam(r, param)
+	return hex.DecodeString(s)
+}
+
+func GetParamInt64(r *http.Request, param string) (int64, error) {
+	s := GetParam(r, param)
+	i, err := strconv.ParseInt(s, 10, 64)
+	if err != nil {
+		return 0, fmt.Errorf(param, err.Error())
+	}
+	return i, nil
+}
+
+func GetParamInt32(r *http.Request, param string) (int32, error) {
+	s := GetParam(r, param)
+	i, err := strconv.ParseInt(s, 10, 32)
+	if err != nil {
+		return 0, fmt.Errorf(param, err.Error())
+	}
+	return int32(i), nil
+}
+
+func GetParamUint64(r *http.Request, param string) (uint64, error) {
+	s := GetParam(r, param)
+	i, err := strconv.ParseUint(s, 10, 64)
+	if err != nil {
+		return 0, fmt.Errorf(param, err.Error())
+	}
+	return i, nil
+}
+
+func GetParamUint(r *http.Request, param string) (uint, error) {
+	s := GetParam(r, param)
+	i, err := strconv.ParseUint(s, 10, 64)
+	if err != nil {
+		return 0, fmt.Errorf(param, err.Error())
+	}
+	return uint(i), nil
+}
+
+func GetParamRegexp(r *http.Request, param string, re *regexp.Regexp) (string, error) {
+	s := GetParam(r, param)
+	if !re.MatchString(s) {
+		return "", fmt.Errorf(param, "Did not match regular expression %v", re.String())
+	}
+	return s, nil
+}
+
+func GetParamFloat64(r *http.Request, param string) (float64, error) {
+	s := GetParam(r, param)
+	f, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		return 0, fmt.Errorf(param, err.Error())
+	}
+	return f, nil
+}

server/http_server.go

@@ -0,0 +1,115 @@
+// Commons for HTTP handling
+package rpcserver
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"net/http"
+	"runtime/debug"
+	"time"
+
+	"github.com/tendermint/go-alert"
+	. "github.com/tendermint/go-common"
+	. "github.com/tendermint/go-rpc/types"
+	"github.com/tendermint/go-wire"
+)
+
+func StartHTTPServer(listenAddr string, handler http.Handler) (net.Listener, error) {
+	log.Notice(Fmt("Starting RPC HTTP server on %v", listenAddr))
+	listener, err := net.Listen("tcp", listenAddr)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to listen to %v", listenAddr)
+	}
+	go func() {
+		res := http.Serve(
+			listener,
+			RecoverAndLogHandler(handler),
+		)
+		log.Crit("RPC HTTP server stopped", "result", res)
+	}()
+	return listener, nil
+}
+
+func WriteRPCResponseHTTP(w http.ResponseWriter, res RPCResponse) {
+	jsonBytes := wire.JSONBytesPretty(res)
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(200)
+	w.Write(jsonBytes)
+}
+
+//-----------------------------------------------------------------------------
+
+// Wraps an HTTP handler, adding error logging.
+// If the inner function panics, the outer function recovers, logs, sends an
+// HTTP 500 error response.
+func RecoverAndLogHandler(handler http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Wrap the ResponseWriter to remember the status
+		rww := &ResponseWriterWrapper{-1, w}
+		begin := time.Now()
+
+		// Common headers
+		origin := r.Header.Get("Origin")
+		rww.Header().Set("Access-Control-Allow-Origin", origin)
+		rww.Header().Set("Access-Control-Allow-Credentials", "true")
+		rww.Header().Set("Access-Control-Expose-Headers", "X-Server-Time")
+		rww.Header().Set("X-Server-Time", fmt.Sprintf("%v", begin.Unix()))
+
+		defer func() {
+			// Send a 500 error if a panic happens during a handler.
+			// Without this, Chrome & Firefox were retrying aborted ajax requests,
+			// at least to my localhost.
+			if e := recover(); e != nil {
+
+				// If RPCResponse
+				if res, ok := e.(RPCResponse); ok {
+					WriteRPCResponseHTTP(rww, res)
+				} else {
+					// For the rest,
+					log.Error("Panic in RPC HTTP handler", "error", e, "stack", string(debug.Stack()))
+					rww.WriteHeader(http.StatusInternalServerError)
+					WriteRPCResponseHTTP(rww, NewRPCResponse("", nil, Fmt("Internal Server Error: %v", e)))
+				}
+			}
+
+			// Finally, log.
+			durationMS := time.Since(begin).Nanoseconds() / 1000000
+			if rww.Status == -1 {
+				rww.Status = 200
+			}
+			log.Info("Served RPC HTTP response",
+				"method", r.Method, "url", r.URL,
+				"status", rww.Status, "duration", durationMS,
+				"remoteAddr", r.RemoteAddr,
+			)
+		}()
+
+		handler.ServeHTTP(rww, r)
+	})
+}
+
+// Remember the status for logging
+type ResponseWriterWrapper struct {
+	Status int
+	http.ResponseWriter
+}
+
+func (w *ResponseWriterWrapper) WriteHeader(status int) {
+	w.Status = status
+	w.ResponseWriter.WriteHeader(status)
+}
+
+// implements http.Hijacker
+func (w *ResponseWriterWrapper) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return w.ResponseWriter.(http.Hijacker).Hijack()
+}
+
+// Stick it as a deferred statement in gouroutines to prevent the program from crashing.
+func Recover(daemonName string) {
+	if e := recover(); e != nil {
+		stack := string(debug.Stack())
+		errorString := fmt.Sprintf("[%s] %s\n%s", daemonName, e, stack)
+		alert.Alert(errorString)
+	}
+}

server/log.go

@@ -0,0 +1,7 @@
+package rpcserver
+
+import (
+	"github.com/tendermint/log15"
+)
+
+var log = log15.New("module", "rpcserver")