rpc: unexport ServerError

It's internal server thing that is not for the outside users.

pkg/rpc/server/error.go

@@ -0,0 +1,66 @@
+package server
+
+import (
+	"net/http"
+
+	"github.com/nspcc-dev/neo-go/pkg/rpc/response"
+)
+
+// serverError represents RPC error response on the server side.
+type serverError struct {
+	*response.Error
+	HTTPCode int // HTTPCode won't be marshalled because Error's marshaller is used.
+}
+
+// abstractResult is an interface which represents either single JSON-RPC 2.0 response
+// or batch JSON-RPC 2.0 response.
+type abstractResult interface {
+	RunForErrors(f func(jsonErr *response.Error))
+}
+
+// abstract represents abstract JSON-RPC 2.0 response. It is used as a server-side response
+// representation.
+type abstract struct {
+	response.Header
+	Error  *serverError `json:"error,omitempty"`
+	Result interface{}  `json:"result,omitempty"`
+}
+
+// RunForErrors implements abstractResult interface.
+func (a abstract) RunForErrors(f func(jsonErr *response.Error)) {
+	if a.Error != nil {
+		f(a.Error.Error)
+	}
+}
+
+// abstractBatch represents abstract JSON-RPC 2.0 batch-response.
+type abstractBatch []abstract
+
+// RunForErrors implements abstractResult interface.
+func (ab abstractBatch) RunForErrors(f func(jsonErr *response.Error)) {
+	for _, a := range ab {
+		if a.Error != nil {
+			f(a.Error.Error)
+		}
+	}
+}
+
+func packClientError(respErr *response.Error) *serverError {
+	var httpCode int
+	switch respErr.Code {
+	case response.BadRequestCode:
+		httpCode = http.StatusBadRequest
+	case response.InvalidRequestCode, response.RPCErrorCode, response.InvalidParamsCode:
+		httpCode = http.StatusUnprocessableEntity
+	case response.MethodNotFoundCode:
+		httpCode = http.StatusMethodNotAllowed
+	case response.InternalServerErrorCode:
+		httpCode = http.StatusInternalServerError
+	default:
+		httpCode = http.StatusUnprocessableEntity
+	}
+	return &serverError{
+		Error:    respErr,
+		HTTPCode: httpCode,
+	}
+}