package jsonrpc2
import (
"bufio"
"context"
"encoding/json"
"io"
"net/http"
"sync"
)
const version = "2.0"
type Server struct {
Logger Logger
IgnoreNotifications bool
handlers map[string]Handler
mu sync.RWMutex
}
func (r *Server) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
writer.Header().Set("Content-Type", "application/json")
buf := bufio.NewReader(request.Body)
defer request.Body.Close()
firstByte, err := buf.Peek(1)
if err != nil {
r.Logger.Logf("Can't read body: %v", err)
writeError(ErrCodeParseError, writer)
return
}
if string(firstByte) == "[" {
r.batchRequest(writer, request, buf)
return
}
r.singleRequest(writer, request, buf)
}
func New() *Server {
return &Server{
Logger: nopLogger{},
IgnoreNotifications: true,
handlers: map[string]Handler{},
mu: sync.RWMutex{},
}
}
func (r *Server) Register(method string, handler Handler) {
r.mu.Lock()
defer r.mu.Unlock()
r.handlers[method] = handler
}
func (r *Server) singleRequest(writer http.ResponseWriter, request *http.Request, buf *bufio.Reader) {
req := new(rpcRequest)
if err := json.NewDecoder(buf).Decode(req); err != nil {
r.Logger.Logf("Can't read body: %v", err)
writeError(ErrCodeParseError, writer)
return
}
resp := r.callMethod(request.Context(), 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 *Server) batchRequest(writer http.ResponseWriter, request *http.Request, buf *bufio.Reader) {
var req []rpcRequest
if err := json.NewDecoder(buf).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(request.Context(), &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 *Server) 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"`
}
