return distinct error type on input error

torrent/error.go

@@ -0,0 +1,40 @@
+package torrent
+
+import (
+	"github.com/cenkalti/rain/internal/announcer"
+)
+
+// InputError is returned from Session.AddTorrent and Session.AddURI methods when there is problem with the input.
+type InputError struct {
+	err error
+}
+
+func newInputError(err error) *InputError {
+	return &InputError{
+		err: err,
+	}
+}
+
+func (e *InputError) Error() string {
+	return "input error: " + e.err.Error()
+}
+
+func (e *InputError) Unwrap() error {
+	return e.err
+}
+
+type AnnounceError struct {
+	err *announcer.AnnounceError
+}
+
+func (e *AnnounceError) Error() string {
+	return e.err.Message
+}
+
+func (e *AnnounceError) Unwrap() error {
+	return e.err.Err
+}
+
+func (e *AnnounceError) Unknown() bool {
+	return e.err.Unknown
+}

torrent/session_add.go

@@ -52,7 +52,7 @@ func (s *Session) addTorrentStopped(r io.Reader, opt *AddTorrentOptions) (*Torre
 	r = io.LimitReader(r, int64(s.config.MaxTorrentSize))
 	mi, err := s.parseMetaInfo(r)
 	if err != nil {
-		return nil, err
+		return nil, newInputError(err)
 	}
 	id, port, sto, err := s.add(opt)
 	if err != nil {
@@ -109,7 +109,7 @@ func (s *Session) AddURI(uri string, opt *AddTorrentOptions) (*Torrent, error) {
 
 	u, err := url.Parse(uri)
 	if err != nil {
-		return nil, err
+		return nil, newInputError(err)
 	}
 	switch u.Scheme {
 	case "http", "https":
@@ -140,12 +140,12 @@ func (s *Session) addURL(u string, opt *AddTorrentOptions) (*Torrent, error) {
 	}
 	resp, err := client.Get(u)
 	if err != nil {
-		return nil, err
+		return nil, newInputError(err)
 	}
 	defer resp.Body.Close()
 
 	if resp.ContentLength > int64(s.config.MaxTorrentSize) {
-		return nil, fmt.Errorf("torrent too large: %d", resp.ContentLength)
+		return nil, newInputError(fmt.Errorf("torrent too large: %d", resp.ContentLength))
 	}
 	r := io.LimitReader(resp.Body, int64(s.config.MaxTorrentSize))
 	return s.AddTorrent(r, opt)
@@ -154,7 +154,7 @@ func (s *Session) addURL(u string, opt *AddTorrentOptions) (*Torrent, error) {
 func (s *Session) addMagnet(link string, opt *AddTorrentOptions) (*Torrent, error) {
 	ma, err := magnet.New(link)
 	if err != nil {
-		return nil, err
+		return nil, newInputError(err)
 	}
 	id, port, sto, err := s.add(opt)
 	if err != nil {

torrent/session_rpc_handler.go

@@ -5,6 +5,7 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -45,6 +46,10 @@ func (h *rpcHandler) AddTorrent(args *rpctypes.AddTorrentRequest, reply *rpctype
 		ID:      args.AddTorrentOptions.ID,
 	}
 	t, err := h.session.AddTorrent(r, opt)
+	var e *InputError
+	if errors.As(err, &e) {
+		return jsonrpc2.NewError(2, e.Error())
+	}
 	if err != nil {
 		return err
 	}
@@ -58,6 +63,10 @@ func (h *rpcHandler) AddURI(args *rpctypes.AddURIRequest, reply *rpctypes.AddURI
 		ID:      args.AddTorrentOptions.ID,
 	}
 	t, err := h.session.AddURI(args.URI, opt)
+	var e *InputError
+	if errors.As(err, &e) {
+		return jsonrpc2.NewError(2, e.Error())
+	}
 	if err != nil {
 		return err
 	}

torrent/torrent_commands.go

@@ -5,7 +5,6 @@ import (
 	"net"
 	"time"
 
-	"github.com/cenkalti/rain/internal/announcer"
 	"github.com/cenkalti/rain/internal/magnet"
 	"github.com/cenkalti/rain/internal/metainfo"
 	"github.com/cenkalti/rain/internal/tracker"
@@ -194,22 +193,6 @@ type Tracker struct {
 	NextAnnounce time.Time
 }
 
-type AnnounceError struct {
-	err *announcer.AnnounceError
-}
-
-func (e *AnnounceError) Error() string {
-	return e.err.Message
-}
-
-func (e *AnnounceError) Unwrap() error {
-	return e.err.Err
-}
-
-func (e *AnnounceError) Unknown() bool {
-	return e.err.Unknown
-}
-
 type trackersRequest struct {
 	Response chan []Tracker
 }