// Create a local fallback for the given script, downloading it if
// necessary
func scriptFallback(m *Manager, script *Asset, fallback string) (*Asset, error) {
fallbackName := script.Name
if !m.Has(fallbackName) {
var scriptURL string
if urlutil.IsURL(fallbackName) {
scriptURL = fallbackName
fallbackName = "asset.gen." + hashutil.Adler32(fallbackName) + "." + path.Base(fallbackName)
} else {
cdn, _, err := Cdn(fallbackName)
if err != nil {
return nil, err
}
scriptURL = cdn
}
if !m.Has(fallbackName) {
u, err := url.Parse(scriptURL)
if err != nil {
return nil, err
}
if u.Scheme == "" {
u.Scheme = "http"
}
log.Debugf("fetching local fallback for %s to %s", u, fallbackName)
resp, err := http.Get(u.String())
if err != nil {
return nil, err
}
defer resp.Body.Close()
w, err := m.Create(fallbackName, true)
if err != nil {
return nil, err
}
defer w.Close()
if _, err := io.Copy(w, resp.Body); err != nil {
return nil, err
}
}
}
return &Asset{
Name: fallbackName,
Position: Bottom,
Type: TypeOther,
HTML: fmt.Sprintf("<script>%s || document.write('<scr'+'ipt src=\"%s\"><\\/scr'+'ipt>')</script>", fallback, m.URL(fallbackName)),
}, nil
}
func (m *Manager) URL(name string) string {
if urlutil.IsURL(name) {
return name
}
m.mutex.RLock()
h, ok := m.cache[name]
m.mutex.RUnlock()
if !ok {
h, _ = m.hash(name)
m.mutex.Lock()
m.cache[name] = h
m.mutex.Unlock()
}
clean := path.Clean(path.Join(m.prefix, name))
if h != "" {
return clean + "?v=" + h
}
return clean
}