fix exception when handling http status

internal/transport/http.go

@@ -91,6 +91,10 @@ func (h *HTTP) Stat() (info fs.FileInfo, err error) {
 	}
 	defer response.Body.Close()
 	
+	if response.StatusCode > 399 {
+		err = ErrTransportResourceAbsent
+		return
+	}
 	fi := NewHTTPFileInfo(uri)
 	contentLength := response.Header.Get("Content-Length")
 	if contentLength != "" {

internal/transport/transport.go

@@ -3,7 +3,7 @@
 package transport
 
 import (
-_	"errors"
+	"errors"
 _	"fmt"
 	"net/url"
 	"net/http"
@@ -15,6 +15,10 @@ _	"os"
 	"context"
 )
 
+var (
+	ErrTransportResourceAbsent error = errors.New("Transport resource is absent")
+)
+
 type Handler interface {
 	URI() *url.URL
 	ContentType() string
@@ -162,11 +166,19 @@ func (r *Reader) AddHeader(name string, value string) {
 }
 
 func (r *Reader) Status() string {
-	return r.handle.(*HTTPReader).GetResponse().Status
+	if httpReader, ok := r.handle.(*HTTPReader); ok {
+		return httpReader.GetResponse().Status
+	}
+	panic("Unable to get HTTP status from reader")
+	return ""
 }
 
 func (r *Reader) StatusCode() int {
-	return r.handle.(*HTTPReader).GetResponse().StatusCode
+	if httpReader, ok := r.handle.(*HTTPReader); ok {
+		return httpReader.GetResponse().StatusCode
+	}
+	panic("Unable to get HTTP status code from reader")
+	return 0
 }
 
 func (r *Reader) Response() *http.Response {