redirect to desired page after authenticating

internal/domains/authentication/auth.go

@@ -100,27 +100,28 @@ func (a *Authenticator) RunBackgroundCleanup(ctx context.Context) error {
 }
 
 // Exchange exchanges an auth code for an access token.
-func (a *Authenticator) Exchange(ctx context.Context, state, code string) (accessToken string, expiration time.Time, err error) {
+func (a *Authenticator) Exchange(ctx context.Context, state, code string) (accessToken, targetURI string, expiration time.Time, err error) {
 	// validate state
 
-	if exp, err := a.GetStateExpiration(ctx, state); errors.Is(err, consts.ErrNotFound) {
-		return "", time.Time{}, fmt.Errorf("invalid state: %w", consts.ErrNotFound)
+	exp, targetURI, err := a.GetStateExpirationAndURL(ctx, state)
+	if errors.Is(err, consts.ErrNotFound) {
+		return "", "", time.Time{}, fmt.Errorf("invalid state: %w", consts.ErrNotFound)
 	} else if err != nil {
-		return "", time.Time{}, fmt.Errorf("failed to load state expiration: %w", err)
+		return "", "", time.Time{}, fmt.Errorf("failed to load state expiration: %w", err)
 	} else if exp.Before(time.Now()) {
-		return "", time.Time{}, fmt.Errorf("invalid state: state expired")
+		return "", "", time.Time{}, fmt.Errorf("invalid state: state expired")
 	}
 
 	// obtain token and profile
 
 	tkn, err := a.Config.Exchange(ctx, code)
 	if err != nil {
-		return "", time.Time{}, fmt.Errorf("failed to exchange an authorization code for a token: %w", err)
+		return "", "", time.Time{}, fmt.Errorf("failed to exchange an authorization code for a token: %w", err)
 	}
 
 	idToken, claims, err := a.verifyIDTokenAndClaimsFromToken(ctx, tkn)
 	if err != nil {
-		return "", time.Time{}, err
+		return "", "", time.Time{}, err
 	}
 
 	claimsJSON, _ := json.Marshal(claims)
@@ -200,10 +201,10 @@ func (a *Authenticator) Exchange(ctx context.Context, state, code string) (acces
 			"claims": json.RawMessage(claimsJSON),
 		},
 	); err != nil {
-		return "", time.Time{}, fmt.Errorf("failed to perform query to save tokens: %w", err)
+		return "", "", time.Time{}, fmt.Errorf("failed to perform query to save tokens: %w", err)
 	}
 
-	return tkn.AccessToken, tkn.Expiry.UTC(), nil
+	return tkn.AccessToken, targetURI, tkn.Expiry.UTC(), nil
 }
 
 // VerifyIDToken verifies that an *oauth2.Token is a valid *oidc.IDToken.