package nonces import ( "errors" "fmt" "net/http" "sync" "github.com/xenolf/lego/acme/api/internal/sender" ) // Manager Manages nonces. type Manager struct { do *sender.Doer nonceURL string nonces []string sync.Mutex } // NewManager Creates a new Manager. func NewManager(do *sender.Doer, nonceURL string) *Manager { return &Manager{ do: do, nonceURL: nonceURL, } } // Pop Pops a nonce. func (n *Manager) Pop() (string, bool) { n.Lock() defer n.Unlock() if len(n.nonces) == 0 { return "", false } nonce := n.nonces[len(n.nonces)-1] n.nonces = n.nonces[:len(n.nonces)-1] return nonce, true } // Push Pushes a nonce. func (n *Manager) Push(nonce string) { n.Lock() defer n.Unlock() n.nonces = append(n.nonces, nonce) } // Nonce implement jose.NonceSource func (n *Manager) Nonce() (string, error) { if nonce, ok := n.Pop(); ok { return nonce, nil } return n.getNonce() } func (n *Manager) getNonce() (string, error) { resp, err := n.do.Head(n.nonceURL) if err != nil { return "", fmt.Errorf("failed to get nonce from HTTP HEAD -> %v", err) } return GetFromResponse(resp) } // GetFromResponse Extracts a nonce from a HTTP response. func GetFromResponse(resp *http.Response) (string, error) { if resp == nil { return "", errors.New("nil response") } nonce := resp.Header.Get("Replay-Nonce") if nonce == "" { return "", fmt.Errorf("server did not respond with a proper nonce header") } return nonce, nil }