func()

in proxy/registryoverride/server.go [63:140]

• 67 lines of code
• 16 McCabe index (conditional complexity)

func (s *Server) catalogHandler(w http.ResponseWriter, r *http.Request) error {
	limitQ := "n"
	offsetQ := "last"

	// Build request for ListWithPagination.
	var filter tagclient.ListFilter
	u := r.URL
	q := u.Query()
	for k, v := range q {
		if len(v) != 1 {
			return handler.Errorf(
				"invalid query %s:%s", k, v).Status(http.StatusBadRequest)
		}
		switch k {
		case limitQ:
			limitCount, err := strconv.Atoi(v[0])
			if err != nil {
				return handler.Errorf(
					"invalid limit %s: %s", v, err).Status(http.StatusBadRequest)
			}
			if limitCount == 0 {
				return handler.Errorf(
					"invalid limit %d", limitCount).Status(http.StatusBadRequest)
			}
			filter.Limit = limitCount
		case offsetQ:
			filter.Offset = v[0]
		default:
			return handler.Errorf("invalid query %s", k).Status(http.StatusBadRequest)
		}
	}

	// List with pagination.
	listResp, err := s.tagClient.ListWithPagination("", filter)
	if err != nil {
		return handler.Errorf("list: %s", err)
	}
	repos := stringset.New()
	for _, tag := range listResp.Result {
		parts := strings.Split(tag, ":")
		if len(parts) != 2 {
			log.With("tag", tag).Errorf("Invalid tag format, expected repo:tag")
			continue
		}
		repos.Add(parts[0])
	}

	// Build Link for response.
	offset, err := listResp.GetOffset()
	if err != nil && err != io.EOF {
		return handler.Errorf("invalid offset %s", err)
	}
	if offset != "" {
		nextUrl, err := url.Parse(u.String())
		if err != nil {
			return handler.Errorf(
				"invalid url string: %s", err).Status(http.StatusBadRequest)
		}
		val, err := url.ParseQuery(nextUrl.RawQuery)
		if err != nil {
			return handler.Errorf(
				"invalid url string: %s", err).Status(http.StatusBadRequest)
		}
		val.Set(offsetQ, offset)
		nextUrl.RawQuery = val.Encode()

		// Set header (https://docs.docker.com/registry/spec/api/#pagination),
		// except the host and scheme.
		// Link: <<url>?n=2&last=b>; rel="next"
		w.Header().Set("Link", fmt.Sprintf("%s; rel=\"next\"", nextUrl.String()))
	}

	resp := catalogResponse{Repositories: repos.ToSlice()}
	if err := json.NewEncoder(w).Encode(&resp); err != nil {
		return handler.Errorf("json encode: %s", err)
	}
	return nil
}