oauth2: add new RawBody field to oauth2.Token

internal/token.go

@@ -54,6 +54,9 @@ type Token struct {
 	// Raw optionally contains extra metadata from the server
 	// when updating a token.
 	Raw interface{}
+
+	// RawBody is the response body from the oauth2 access token request/response flow
+	RawBody []byte
 }
 
 // tokenJSON is the struct representing the HTTP response from OAuth2
@@ -278,6 +281,7 @@ func doTokenRoundTrip(ctx context.Context, req *http.Request) (*Token, error) {
 		}
 		json.Unmarshal(body, &token.Raw) // no error checks for optional fields
 	}
+	token.RawBody = body
 	if token.AccessToken == "" {
 		return nil, errors.New("oauth2: server response missing access_token")
 	}

token.go

@@ -49,6 +49,10 @@ type Token struct {
 	// mechanisms for that TokenSource will not be used.
 	Expiry time.Time `json:"expiry,omitempty"`
 
+	// RawBody provides access to the raw body response from
+	// the oauth2 authorize flow
+	RawBody []byte `json:"-"`
+
 	// raw optionally contains extra metadata from the server
 	// when updating a token.
 	raw interface{}
@@ -146,6 +150,7 @@ func tokenFromInternal(t *internal.Token) *Token {
 		TokenType:    t.TokenType,
 		RefreshToken: t.RefreshToken,
 		Expiry:       t.Expiry,
+		RawBody:      t.RawBody,
 		raw:          t.Raw,
 	}
 }