Create a ClientError type to distinguish between failure modes

http/routes.go

@@ -38,26 +38,25 @@ func (s *Server) stats(w http.ResponseWriter, r *http.Request, p httprouter.Para
 	return http.StatusOK, nil
 }
 
-func (s *Server) serveAnnounce(w http.ResponseWriter, r *http.Request, p httprouter.Params) (int, error) {
-	ann, err := NewAnnounce(s.config, r, p)
-	writer := &Writer{w}
-
-	if err == models.ErrMalformedRequest {
-		writer.WriteError(err)
+func handleError(err error, w *Writer) (int, error) {
+	if _, ok := err.(*models.ClientError); ok {
+		w.WriteError(err)
 		stats.RecordEvent(stats.BlockedRequest)
 		return http.StatusOK, nil
-	} else if err != nil {
-		return http.StatusInternalServerError, err
 	}
 
-	err = s.tracker.HandleAnnounce(ann, writer)
+	return http.StatusInternalServerError, err
+}
 
-	if err == models.ErrBadRequest {
-		writer.WriteError(err)
-		stats.RecordEvent(stats.BlockedRequest)
-		return http.StatusOK, nil
-	} else if err != nil {
-		return http.StatusInternalServerError, err
+func (s *Server) serveAnnounce(w http.ResponseWriter, r *http.Request, p httprouter.Params) (int, error) {
+	writer := &Writer{w}
+	ann, err := NewAnnounce(s.config, r, p)
+	if err != nil {
+		return handleError(err, writer)
+	}
+
+	if err = s.tracker.HandleAnnounce(ann, writer); err != nil {
+		return handleError(err, writer)
 	}
 
 	stats.RecordEvent(stats.Announce)
@@ -65,23 +64,17 @@ func (s *Server) serveAnnounce(w http.ResponseWriter, r *http.Request, p httprou
 }
 
 func (s *Server) serveScrape(w http.ResponseWriter, r *http.Request, p httprouter.Params) (int, error) {
-	scrape, err := NewScrape(s.config, r, p)
 	writer := &Writer{w}
-
-	if err == models.ErrMalformedRequest {
-		writer.WriteError(err)
-		stats.RecordEvent(stats.BlockedRequest)
-		return http.StatusOK, nil
-	} else if err != nil {
-		return http.StatusInternalServerError, err
+	scrape, err := NewScrape(s.config, r, p)
+	if err != nil {
+		return handleError(err, writer)
 	}
 
 	if err = s.tracker.HandleScrape(scrape, writer); err != nil {
-		return http.StatusInternalServerError, err
+		return handleError(err, writer)
 	}
 
 	stats.RecordEvent(stats.Scrape)
-
 	return http.StatusOK, nil
 }
 

tracker/models/models.go

@@ -5,36 +5,43 @@
 package models
 
 import (
-	"errors"
 	"net"
 	"time"
 
 	"github.com/chihaya/chihaya/config"
 )
 
+type ClientError struct {
+	message string
+}
+
 var (
 	// ErrMalformedRequest is returned when a request does not contain the
 	// required parameters needed to create a model.
-	ErrMalformedRequest = errors.New("malformed request")
+	ErrMalformedRequest = &ClientError{"malformed request"}
 
 	// ErrBadRequest is returned when a request is invalid in the peer's
 	// current state. For example, announcing a "completed" event while
 	// not a leecher or a "stopped" event while not active.
-	ErrBadRequest = errors.New("bad request")
+	ErrBadRequest = &ClientError{"bad request"}
 
 	// ErrUserDNE is returned when a user does not exist.
-	ErrUserDNE = errors.New("user does not exist")
+	ErrUserDNE = &ClientError{"user does not exist"}
 
 	// ErrTorrentDNE is returned when a torrent does not exist.
-	ErrTorrentDNE = errors.New("torrent does not exist")
+	ErrTorrentDNE = &ClientError{"torrent does not exist"}
 
 	// ErrClientUnapproved is returned when a clientID is not in the whitelist.
-	ErrClientUnapproved = errors.New("client is not approved")
+	ErrClientUnapproved = &ClientError{"client is not approved"}
 
 	// ErrInvalidPasskey is returned when a passkey is not properly formatted.
-	ErrInvalidPasskey = errors.New("passkey is invalid")
+	ErrInvalidPasskey = &ClientError{"passkey is invalid"}
 )
 
+func (e *ClientError) Error() string {
+	return e.message
+}
+
 // Peer is a participant in a swarm.
 type Peer struct {
 	ID        string `json:"id"`