From fde57457076c586fea4b371952b6c31635670c84 Mon Sep 17 00:00:00 2001
From: Brent Bumann <brent.bumann@aol.com>
Date: Fri, 21 May 2021 15:42:05 -0700
Subject: [PATCH] Refresh Access token when no expiration is present (#241)

Co-authored-by: Brent Bumann <bbumann@dropbox.com>
---
 dropbox-sdk-dotnet/Dropbox.Api/DropboxRequestHandler.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dropbox-sdk-dotnet/Dropbox.Api/DropboxRequestHandler.cs b/dropbox-sdk-dotnet/Dropbox.Api/DropboxRequestHandler.cs
index 04b3394bd7..0513cbd5ee 100644
--- a/dropbox-sdk-dotnet/Dropbox.Api/DropboxRequestHandler.cs
+++ b/dropbox-sdk-dotnet/Dropbox.Api/DropboxRequestHandler.cs
@@ -640,7 +640,8 @@ private async Task<Result> RequestJsonString(
         private async Task<bool> CheckAndRefreshAccessToken()
         {
             bool canRefresh = this.options.OAuth2RefreshToken != null && this.options.AppKey != null;
-            bool needsRefresh = this.options.OAuth2AccessTokenExpiresAt.HasValue && DateTime.Now.AddSeconds(TokenExpirationBuffer) >= this.options.OAuth2AccessTokenExpiresAt.Value;
+            bool needsRefresh = (this.options.OAuth2AccessTokenExpiresAt.HasValue && DateTime.Now.AddSeconds(TokenExpirationBuffer) >= this.options.OAuth2AccessTokenExpiresAt.Value) ||
+                (this.options.OAuth2RefreshToken != null && !this.options.OAuth2AccessTokenExpiresAt.HasValue);
             bool needsToken = this.options.OAuth2AccessToken == null;
             if ((needsRefresh || needsToken) && canRefresh)
             {