swift: fix crash on bad authentication - fixes #1919

This also fixes Hubic not re-authenticating for long transfers.

swift/auth.go

@@ -1,29 +1,76 @@
 package swift
 
-import "github.com/ncw/swift"
+import (
+	"net/http"
 
-// auth is an authenticator for swift
+	"github.com/ncw/swift"
+)
+
+// auth is an authenticator for swift.  It overrides the StorageUrl
+// and AuthToken with fixed values.
 type auth struct {
-	swift.Authenticator
+	parentAuth swift.Authenticator
 	storageURL string
+	authToken  string
 }
 
 // newAuth creates a swift authenticator wrapper to override the
-// StorageUrl method.
-func newAuth(Authenticator swift.Authenticator, storageURL string) *auth {
+// StorageUrl and AuthToken values.
+//
+// Note that parentAuth can be nil
+func newAuth(parentAuth swift.Authenticator, storageURL string, authToken string) *auth {
 	return &auth{
-		Authenticator: Authenticator,
-		storageURL:    storageURL,
+		parentAuth: parentAuth,
+		storageURL: storageURL,
+		authToken:  authToken,
 	}
 }
 
+// Request creates an http.Request for the auth - return nil if not needed
+func (a *auth) Request(c *swift.Connection) (*http.Request, error) {
+	if a.parentAuth == nil {
+		return nil, nil
+	}
+	return a.parentAuth.Request(c)
+}
+
+// Response parses the http.Response
+func (a *auth) Response(resp *http.Response) error {
+	if a.parentAuth == nil {
+		return nil
+	}
+	return a.parentAuth.Response(resp)
+}
+
 // The public storage URL - set Internal to true to read
 // internal/service net URL
 func (a *auth) StorageUrl(Internal bool) string {
 	if a.storageURL != "" {
 		return a.storageURL
 	}
-	return a.Authenticator.StorageUrl(Internal)
+	if a.parentAuth == nil {
+		return ""
+	}
+	return a.parentAuth.StorageUrl(Internal)
+}
+
+// The access token
+func (a *auth) Token() string {
+	if a.authToken != "" {
+		return a.authToken
+	}
+	if a.parentAuth == nil {
+		return ""
+	}
+	return a.parentAuth.Token()
+}
+
+// The CDN url if available
+func (a *auth) CdnUrl() string {
+	if a.parentAuth == nil {
+		return ""
+	}
+	return a.parentAuth.CdnUrl()
 }
 
 // Check the interfaces are satisfied