// parseSelectedTags parses url for selected tags and redirects if it refers to missing tags
func parseSelectedTags(w http.ResponseWriter, r *http.Request, notebook *tessernote.Notebook, c appengine.Context) ([]tessernote.Tag, error) {
var names []string
if r.URL.Path != "/" && r.URL.Path != untaggedURL {
names = strings.Split(r.URL.Path[1:], tagSeparator)
}
tags, err := notebook.TagsFrom(names, c)
if err != nil {
names = tessernote.Name(tags)
tagString := strings.Join(names, tagSeparator)
http.Redirect(w, r, "/"+tagString, http.StatusFound)
}
return tags, err
}
