1 files changed, 146 insertions, 0 deletions
diff --git a/server.go b/server.go
new file mode 100644
index 0000000..5625f78
--- /dev/null
+++ b/server.go
@@ -0,0 +1,146 @@
+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"`
+}