Check entries but do not remove if they fail

FinalCommander.go

@@ -210,7 +210,7 @@ func handle(ctx *httputils.RequestContext) {
 						continue
 					}
 
-					result := c.CheckEntryKey(key, privateKey)
+					result, err := c.CheckEntryKey(key, privateKey)
 					if result != nil {
 						if e == nil {
 							e = &content.Entry{
@@ -220,7 +220,7 @@ func handle(ctx *httputils.RequestContext) {
 								CheckTime:  time.Now().UTC().Unix() + 3600*24*3, // Check sooner after addition, not all servers might have it yet
 							}
 						}
-					} else {
+					} else if err == nil {
 						newInvalidList = append(newInvalidList, c.Index)
 					}
 				}
@@ -277,7 +277,9 @@ func getContentEntry(key *content.HashIdentifier) *content.Entry {
 						}
 						continue
 					}
-					if c.CheckEntryKey(&e.Key, privateKey) == nil {
+
+					h, err := c.CheckEntryKey(&e.Key, privateKey)
+					if h == nil && err == nil {
 						newInvalidList = append(newInvalidList, c.Index)
 					}
 				}
@@ -366,7 +368,7 @@ func main() {
 
 	go func() {
 		ticker := time.NewTicker(1 * time.Minute)
-		for _ = range ticker.C {
+		for range ticker.C {
 			checkContentServers()
 		}
 	}()

content/server.go

@@ -97,7 +97,7 @@ func (s *Server) Check() {
 	s.setCheckResult(true)
 }
 
-func (s *Server) CheckEntryKey(key *HashIdentifier, privateKey ed25519.PrivateKey) *HashIdentifier {
+func (s *Server) CheckEntryKey(key *HashIdentifier, privateKey ed25519.PrivateKey) (*HashIdentifier, error) {
 	customTransport := http.DefaultTransport.(*http.Transport).Clone()
 	customTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
 	client := &http.Client{
@@ -107,27 +107,31 @@ func (s *Server) CheckEntryKey(key *HashIdentifier, privateKey ed25519.PrivateKe
 	response, err := client.Head(s.GetHashURL(key.Hash(), privateKey, []int{}))
 
 	if err != nil {
-		return nil
+		return nil, err
 	}
 
 	defer response.Body.Close()
 
+	if response.StatusCode == http.StatusNotFound {
+		return nil, nil
+	}
+
 	if response.StatusCode != http.StatusOK {
-		return nil
+		return nil, fmt.Errorf("unexpected status code %d", response.StatusCode)
 	}
 
 	v := strings.Split(response.Header.Get("Digest"), "=")
 	if len(v) >= 2 && v[0] == "sha-256" {
 		sha, err := base64.StdEncoding.DecodeString(strings.Join(v[1:], "="))
 		if err != nil {
-			return nil
+			return nil, nil
 		}
 		mh, err := multihash.Encode(sha, multihash.SHA2_256)
 		if err != nil {
-			return nil
+			return nil, nil
 		}
-		return NewHashIdentifierFromMultihash(mh)
+		return NewHashIdentifierFromMultihash(mh), nil
 	}
 
-	return nil
+	return nil, nil
 }