//Package rpc provides abstract rpc server
//
//Copyright (C) 2022 Alexander Kiryukhin <i@neonxp.dev>
//
//This file is part of go.neonxp.dev/jsonrpc2 project.
//
//This program is free software: you can redistribute it and/or modify
//it under the terms of the GNU General Public License as published by
//the Free Software Foundation, either version 3 of the License, or
//(at your option) any later version.
//
//This program 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 General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program. If not, see <https://www.gnu.org/licenses/>.
package rpc
import (
"context"
"encoding/json"
"io"
"sync"
)
const version = "2.0"
type RpcServer struct {
Logger Logger
IgnoreNotifications bool
handlers map[string]Handler
mu sync.RWMutex
}
func New() *RpcServer {
return &RpcServer{
Logger: nopLogger{},
IgnoreNotifications: true,
handlers: map[string]Handler{},
mu: sync.RWMutex{},
}
}
func (r *RpcServer) Register(method string, handler Handler) {
r.mu.Lock()
defer r.mu.Unlock()
r.handlers[method] = handler
}
func (r *RpcServer) SingleRequest(ctx context.Context, reader io.Reader, writer io.Writer) {
req := new(rpcRequest)
if err := json.NewDecoder(reader).Decode(req); err != nil {
r.Logger.Logf("Can't read body: %v", err)
WriteError(ErrCodeParseError, writer)
return
}
resp := r.callMethod(ctx, req)
if req.Id == nil && r.IgnoreNotifications {
// notification request
return
}
if err := json.NewEncoder(writer).Encode(resp); err != nil {
r.Logger.Logf("Can't write response: %v", err)
WriteError(ErrCodeInternalError, writer)
return
}
}
func (r *RpcServer) BatchRequest(ctx context.Context, reader io.Reader, writer io.Writer) {
var req []rpcRequest
if err := json.NewDecoder(reader).Decode(&req); err != nil {
r.Logger.Logf("Can't read body: %v", err)
WriteError(ErrCodeParseError, writer)
return
}
var responses []*rpcResponse
wg := sync.WaitGroup{}
wg.Add(len(req))
for _, j := range req {
go func(req rpcRequest) {
defer wg.Done()
resp := r.callMethod(ctx, &req)
if req.Id == nil && r.IgnoreNotifications {
// notification request
return
}
responses = append(responses, resp)
}(j)
}
wg.Wait()
if err := json.NewEncoder(writer).Encode(responses); err != nil {
r.Logger.Logf("Can't write response: %v", err)
WriteError(ErrCodeInternalError, writer)
}
}
func (r *RpcServer) callMethod(ctx context.Context, req *rpcRequest) *rpcResponse {
r.mu.RLock()
h, ok := r.handlers[req.Method]
r.mu.RUnlock()
if !ok {
return &rpcResponse{
Jsonrpc: version,
Error: NewError(ErrCodeMethodNotFound),
Id: req.Id,
}
}
resp, err := h(ctx, req.Params)
if err != nil {
r.Logger.Logf("User error %v", err)
return &rpcResponse{
Jsonrpc: version,
Error: err,
Id: req.Id,
}
}
return &rpcResponse{
Jsonrpc: version,
Result: resp,
Id: req.Id,
}
}
func WriteError(code int, w io.Writer) {
_ = json.NewEncoder(w).Encode(rpcResponse{
Jsonrpc: version,
Error: NewError(code),
})
}
type rpcRequest struct {
Jsonrpc string `json:"jsonrpc"`
Method string `json:"method"`
Params json.RawMessage `json:"params"`
Id any `json:"id"`
}
type rpcResponse struct {
Jsonrpc string `json:"jsonrpc"`
Result json.RawMessage `json:"result,omitempty"`
Error error `json:"error,omitempty"`
Id any `json:"id,omitempty"`
}
