feat: rp.RefreshAccessToken() now may provide an updated IDToken (#365)

pkg/client/client.go

@@ -61,12 +61,18 @@ func callTokenEndpoint(request interface{}, authFn interface{}, caller TokenEndp
 	if err := httphelper.HttpRequest(caller.HttpClient(), req, &tokenRes); err != nil {
 		return nil, err
 	}
-	return &oauth2.Token{
+	token := &oauth2.Token{
 		AccessToken:  tokenRes.AccessToken,
 		TokenType:    tokenRes.TokenType,
 		RefreshToken: tokenRes.RefreshToken,
 		Expiry:       time.Now().UTC().Add(time.Duration(tokenRes.ExpiresIn) * time.Second),
-	}, nil
+	}
+	if tokenRes.IDToken != "" {
+		token = token.WithExtra(map[string]any{
+			"id_token": tokenRes.IDToken,
+		})
+	}
+	return token, nil
 }
 
 type EndSessionCaller interface {

pkg/client/integration_test.go

@@ -53,6 +53,7 @@ func TestRelyingPartySession(t *testing.T) {
 	t.Logf("new token type %s", newTokens.TokenType)
 	t.Logf("new expiry %s", newTokens.Expiry.Format(time.RFC3339))
 	require.NotEmpty(t, newTokens.AccessToken, "new accessToken")
+	assert.NotEmpty(t, newTokens.Extra("id_token"), "new idToken")
 
 	t.Log("------ end session (logout) ------")
 
@@ -141,7 +142,6 @@ func TestResourceServerTokenExchange(t *testing.T) {
 	require.Error(t, err, "refresh token")
 	assert.Contains(t, err.Error(), "subject_token is invalid")
 	require.Nil(t, tokenExchangeResponse, "token exchange response")
-
 }
 
 func RunAuthorizationCodeFlow(t *testing.T, opServer *httptest.Server, clientID, clientSecret string) (provider rp.RelyingParty, accessToken, refreshToken, idToken string) {

pkg/client/profile/jwt_profile.go

@@ -13,7 +13,7 @@ import (
 
 // jwtProfileTokenSource implement the oauth2.TokenSource
 // it will request a token using the OAuth2 JWT Profile Grant
-// therefore sending an `assertion` by singing a JWT with the provided private key
+// therefore sending an `assertion` by signing a JWT with the provided private key
 type jwtProfileTokenSource struct {
 	clientID      string
 	audience      []string

pkg/client/rp/relying_party.go

@@ -620,6 +620,10 @@ type RefreshTokenRequest struct {
 	GrantType           oidc.GrantType           `schema:"grant_type"`
 }
 
+// RefreshAccessToken performs a token refresh. If it doesn't error, it will always
+// provide a new AccessToken. It may provide a new RefreshToken, and if it does, then
+// the old one should be considered invalid. It may also provide a new IDToken. The
+// new IDToken can be retrieved with token.Extra("id_token").
 func RefreshAccessToken(rp RelyingParty, refreshToken, clientAssertion, clientAssertionType string) (*oauth2.Token, error) {
 	request := RefreshTokenRequest{
 		RefreshToken:        refreshToken,