Refresh token helper

cmd/gmailctl/cmd/api_provider.go

@@ -31,6 +31,12 @@ type APIKeyProvider interface {
 	APIKey() string
 }
 
+// TokenRefresher allows to refresh API tokens if they are expired.
+type TokenRefresher interface {
+	// RefreshToken refreshes the token if it is expired.
+	RefreshToken(ctx context.Context, cfgDir string) error
+}
+
 func openAPI() (*api.GmailAPI, error) {
 	srv, err := APIProvider.Service(context.Background(), cfgDir)
 	if err != nil {

cmd/gmailctl/cmd/apply_cmd.go

@@ -20,6 +20,7 @@ const renameLabelWarning = `Warning: You are going to delete labels. This operat
 irreversible, because it also removes those labels from messages.
 
 If you are looking for renaming labels, please use the GMail UI.
+
 `
 
 // applyCmd represents the apply command
@@ -84,7 +85,7 @@ func apply(path string, interactive, test bool) error {
 	}
 
 	if len(diff.LabelsDiff.Removed) > 0 {
-		fmt.Println(renameLabelWarning)
+		fmt.Print(renameLabelWarning)
 		if !applyRemoveLabels {
 			return errors.WithDetails(errors.New("no changes have been made"),
 				"To protect you, deletion is disabled unless you\n"+

cmd/gmailctl/cmd/init_cmd.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 	"os"
 	"path"
@@ -10,7 +11,10 @@ import (
 	"github.com/mbrt/gmailctl/internal/data"
 )
 
-var initReset bool
+var (
+	initReset          bool
+	initRefreshExpired bool
+)
 
 // initCmd represents the init command
 var initCmd = &cobra.Command{
@@ -23,6 +27,8 @@ setting up the API authorizations and initial settings.`,
 		var err error
 		if initReset {
 			err = resetConfig()
+		} else if initRefreshExpired {
+			err = refreshToken()
 		} else {
 			err = continueConfig()
 		}
@@ -37,6 +43,7 @@ func init() {
 
 	// Flags and configuration settings
 	initCmd.Flags().BoolVar(&initReset, "reset", false, "Reset the configuration.")
+	initCmd.Flags().BoolVar(&initRefreshExpired, "refresh-expired", false, "Refresh auth token if expired.")
 }
 
 func resetConfig() error {
@@ -58,6 +65,13 @@ func continueConfig() error {
 	return nil
 }
 
+func refreshToken() error {
+	if rt, ok := APIProvider.(TokenRefresher); ok {
+		return rt.RefreshToken(context.Background(), cfgDir)
+	}
+	return nil
+}
+
 func handleCfgDir() (err error) {
 	// Create the config dir
 	if _, err := os.Stat(cfgDir); err != nil {

cmd/gmailctl/localcred/local_provider.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/mbrt/gmailctl/cmd/gmailctl/cmd"
 	"github.com/mbrt/gmailctl/internal/engine/api"
+	"github.com/mbrt/gmailctl/internal/errors"
 )
 
 const (
@@ -88,6 +89,23 @@ func (Provider) ResetConfig(cfgDir string) error {
 	return nil
 }
 
+func (Provider) RefreshToken(ctx context.Context, cfgDir string) error {
+	auth, err := openCredentials(credentialsPath(cfgDir))
+	if err != nil {
+		return errors.WithDetails(fmt.Errorf("invalid credentials: %w", err),
+			"Please run 'gmailctl init' to initialize the credentials.")
+	}
+	svc, err := openToken(ctx, auth, tokenPath(cfgDir))
+	if err != nil {
+		return setupToken(auth, tokenPath(cfgDir))
+	}
+	// Check whether the token works by getting a label.
+	if _, err := svc.Users.Labels.Get("me", "INBOX").Context(ctx).Do(); err != nil {
+		return setupToken(auth, tokenPath(cfgDir))
+	}
+	return nil
+}
+
 func openCredentials(path string) (*api.Authenticator, error) {
 	cred, err := os.Open(path)
 	if err != nil {