Merge pull request #2448 from kklin/follow-relative-links

Properly follow relative links when listing tags

registry/client/repository.go

@@ -205,13 +205,18 @@ type tags struct {
 func (t *tags) All(ctx context.Context) ([]string, error) {
 	var tags []string
 
-	u, err := t.ub.BuildTagsURL(t.name)
+	listURLStr, err := t.ub.BuildTagsURL(t.name)
+	if err != nil {
+		return tags, err
+	}
+
+	listURL, err := url.Parse(listURLStr)
 	if err != nil {
 		return tags, err
 	}
 
 	for {
-		resp, err := t.client.Get(u)
+		resp, err := t.client.Get(listURL.String())
 		if err != nil {
 			return tags, err
 		}
@@ -231,7 +236,13 @@ func (t *tags) All(ctx context.Context) ([]string, error) {
 			}
 			tags = append(tags, tagsResponse.Tags...)
 			if link := resp.Header.Get("Link"); link != "" {
-				u = strings.Trim(strings.Split(link, ";")[0], "<>")
+				linkURLStr := strings.Trim(strings.Split(link, ";")[0], "<>")
+				linkURL, err := url.Parse(linkURLStr)
+				if err != nil {
+					return tags, err
+				}
+
+				listURL = listURL.ResolveReference(linkURL)
 			} else {
 				return tags, nil
 			}

registry/client/repository_test.go

@@ -1136,13 +1136,27 @@ func TestManifestTagsPaginated(t *testing.T) {
 			queryParams["n"] = []string{"1"}
 			queryParams["last"] = []string{tagsList[i-1]}
 		}
+
+		// Test both relative and absolute links.
+		relativeLink := "/v2/" + repo.Name() + "/tags/list?n=1&last=" + tagsList[i]
+		var link string
+		switch i {
+		case 0:
+			link = relativeLink
+		case len(tagsList) - 1:
+			link = ""
+		default:
+			link = s.URL + relativeLink
+		}
+
 		headers := http.Header(map[string][]string{
 			"Content-Length": {fmt.Sprint(len(body))},
 			"Last-Modified":  {time.Now().Add(-1 * time.Second).Format(time.ANSIC)},
 		})
-		if i < 2 {
-			headers.Set("Link", "<"+s.URL+"/v2/"+repo.Name()+"/tags/list?n=1&last="+tagsList[i]+`>; rel="next"`)
+		if link != "" {
+			headers.Set("Link", fmt.Sprintf(`<%s>; rel="next"`, link))
 		}
+
 		m = append(m, testutil.RequestResponseMapping{
 			Request: testutil.Request{
 				Method:      "GET",