From: Matt Joiner <anacrolix@gmail.com>
Date: Thu, 18 Feb 2021 03:36:08 +0000 (+1100)
Subject: Treat 404 responses from webseed peers as fatal
X-Git-Tag: v1.26.0-alpha~19
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=af0ade549644f77350be2cd5b4c0d8b6f680259e;p=btrtrc.git

Treat 404 responses from webseed peers as fatal

Fixes #464.
---

diff --git a/webseed-peer.go b/webseed-peer.go
index e436f8aa..e2df582e 100644
--- a/webseed-peer.go
+++ b/webseed-peer.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/http"
 	"strings"
 	"sync"
 
@@ -117,11 +118,18 @@ func (ws *webseedPeer) requestResultHandler(r Request, webseedRequest webseed.Re
 		if !errors.Is(result.Err, context.Canceled) {
 			ws.peer.logger.Printf("Request %v rejected: %v", r, result.Err)
 		}
-		// Always close for now. We need to filter out temporary errors, but this is a nightmare in
-		// Go. Currently a bad webseed URL can starve out the good ones due to the chunk selection
-		// algorithm.
+		// We need to filter out temporary errors, but this is a nightmare in Go. Currently a bad
+		// webseed URL can starve out the good ones due to the chunk selection algorithm.
 		const closeOnAllErrors = false
-		if closeOnAllErrors || strings.Contains(result.Err.Error(), "unsupported protocol scheme") {
+		if closeOnAllErrors ||
+			strings.Contains(result.Err.Error(), "unsupported protocol scheme") ||
+			func() bool {
+				var err webseed.ErrBadResponse
+				if !errors.As(result.Err, &err) {
+					return false
+				}
+				return err.Response.StatusCode == http.StatusNotFound
+			}() {
 			ws.peer.close()
 		} else {
 			ws.peer.remoteRejectedRequest(r)
diff --git a/webseed/client.go b/webseed/client.go
index 420901ea..cc17b339 100644
--- a/webseed/client.go
+++ b/webseed/client.go
@@ -3,7 +3,6 @@ package webseed
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -86,6 +85,15 @@ func (ws *Client) NewRequest(r RequestSpec) Request {
 	return req
 }
 
+type ErrBadResponse struct {
+	Msg      string
+	Response *http.Response
+}
+
+func (me ErrBadResponse) Error() string {
+	return me.Msg
+}
+
 func recvPartResult(buf io.Writer, part requestPart) error {
 	result := <-part.result
 	if result.err != nil {
@@ -96,10 +104,13 @@ func recvPartResult(buf io.Writer, part requestPart) error {
 	case http.StatusPartialContent:
 	case http.StatusOK:
 		if part.e.Start != 0 {
-			return errors.New("got status ok but request was at offset")
+			return ErrBadResponse{"got status ok but request was at offset", result.resp}
 		}
 	default:
-		return fmt.Errorf("unhandled response status code (%v)", result.resp.StatusCode)
+		return ErrBadResponse{
+			fmt.Sprintf("unhandled response status code (%v)", result.resp.StatusCode),
+			result.resp,
+		}
 	}
 	copied, err := io.Copy(buf, result.resp.Body)
 	if err != nil {