RPC server

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

daemon/builder.go

@@ -1,3 +1 @@
 package daemon
-
-

daemon/modules/testing.go

@@ -1,3 +1 @@
 package modules
-
-

daemon/rpc.go

@@ -1,31 +1,27 @@
 package daemon
 
 import (
+	"fmt"
 	"net/http"
 
-	"github.com/gorilla/rpc/v2"
-	"github.com/gorilla/rpc/v2/json"
-
 	"github.com/filecoin-project/go-lotus/build"
+	"github.com/filecoin-project/go-lotus/rpclib"
 )
 
 type Filecoin struct{}
 
-func (*Filecoin) ServerVersion(r *http.Request, _ *struct{}, out *string) error {
-	*out = build.Version
-	return nil
+func (*Filecoin) ServerVersion(in int) (string, error) {
+	fmt.Println(in)
+	return build.Version, nil
 }
 
 func serveRPC() error {
 	fc := new(Filecoin)
 
-	rpcServer := rpc.NewServer()
-	rpcServer.RegisterCodec(json.NewCodec(), "application/json")
-	if err := rpcServer.RegisterService(fc, ""); err != nil {
-		return err
-	}
+	rpcServer := rpclib.NewServer()
+
+	rpcServer.Register(fc)
 
 	http.Handle("/rpc/v0", rpcServer)
 	return http.ListenAndServe(":1234", http.DefaultServeMux)
 }
-

rpclib/rpc.go

@@ -0,0 +1,164 @@
+package rpclib
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"reflect"
+)
+
+type rpcHandler struct {
+	paramReceivers []reflect.Type
+	nParams        int
+
+	receiver    reflect.Value
+	handlerFunc reflect.Value
+
+	errOut int
+	valOut int
+}
+
+type RPCServer struct {
+	methods map[string]rpcHandler
+}
+
+func NewServer() *RPCServer {
+	return &RPCServer{
+		methods: map[string]rpcHandler{},
+	}
+}
+
+type param struct {
+	data []byte
+}
+
+func (p *param) UnmarshalJSON(raw []byte) error {
+	p.data = make([]byte, len(raw))
+	copy(p.data, raw)
+	return nil
+}
+
+type request struct {
+	Jsonrpc string  `json:"jsonrpc"`
+	Id      *int    `json:"id,omitempty"`
+	Method  string  `json:"method"`
+	Params  []param `json:"params"`
+}
+
+type respError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+type response struct {
+	Jsonrpc string      `json:"jsonrpc"`
+	Result  interface{} `json:"result"`
+	Id      int         `json:"id"`
+	Error   *respError  `json:"error,omitempty"`
+}
+
+func (s *RPCServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var req request
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		w.WriteHeader(500)
+		return
+	}
+
+	handler, ok := s.methods[req.Method]
+	if !ok {
+		w.WriteHeader(500)
+		return
+	}
+
+	callParams := make([]reflect.Value, 1+handler.nParams)
+	callParams[0] = handler.receiver
+	for i := 0; i < handler.nParams; i++ {
+		rp := reflect.New(handler.paramReceivers[i])
+		if err := json.NewDecoder(bytes.NewReader(req.Params[i].data)).Decode(rp.Interface()); err != nil {
+			w.WriteHeader(500)
+			fmt.Println(err)
+			return
+		}
+
+		callParams[i+1] = reflect.ValueOf(rp.Elem().Interface())
+	}
+
+	callResult := handler.handlerFunc.Call(callParams)
+	if req.Id == nil {
+		return // notification
+	}
+
+	resp := response{
+		Jsonrpc: "2.0",
+		Id:      *req.Id,
+	}
+
+	if handler.errOut != -1 {
+		err := callResult[handler.errOut].Interface()
+		if err != nil {
+			resp.Error = &respError{
+				Code:    1,
+				Message: err.(error).Error(),
+			}
+		}
+	}
+	if handler.valOut != -1 {
+		resp.Result = callResult[handler.valOut].Interface()
+	}
+
+	json.NewEncoder(os.Stderr).Encode(resp)
+}
+
+func (s *RPCServer) Register(r interface{}) {
+	val := reflect.ValueOf(r)
+	//TODO: expect ptr
+
+	name := val.Type().Elem().Name()
+
+	for i := 0; i < val.NumMethod(); i++ {
+		method := val.Type().Method(i)
+
+		fmt.Println(name + "." + method.Name)
+
+		funcType := method.Func.Type()
+		ins := funcType.NumIn() - 1
+		recvs := make([]reflect.Type, ins)
+		for i := 0; i < ins; i++ {
+			recvs[i] = method.Type.In(i + 1)
+		}
+
+		errOut := -1
+		valOut := -1
+
+		switch funcType.NumOut() {
+		case 0:
+		case 1:
+			if funcType.Out(0) == reflect.TypeOf(new(error)).Elem() {
+				errOut = 0
+			} else {
+				valOut = 0
+			}
+		case 2:
+			valOut = 0
+			errOut = 1
+			if funcType.Out(1) != reflect.TypeOf(new(error)).Elem() {
+				panic("expected error as second return value")
+			}
+		default:
+			panic("too many error values")
+		}
+
+		s.methods[name+"."+method.Name] = rpcHandler{
+			paramReceivers: recvs,
+			nParams:        ins,
+
+			handlerFunc: method.Func,
+			receiver:    val,
+
+			errOut: errOut,
+			valOut: valOut,
+		}
+	}
+}