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"` }