From a9058796d8174853a903c9b4bf8a17035f4fa60b Mon Sep 17 00:00:00 2001
From: Andy Rudd <arudd@htec.co.uk>
Date: Fri, 14 Jul 2017 10:16:36 +0100
Subject: [PATCH] Check automatic refresh interval before refreshing the
 security tokens.

---
 .../DiscoveryDocumentIssuerSecurityTokenProvider.cs      | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/source/AccessTokenValidation/Plumbing/DiscoveryDocumentIssuerSecurityTokenProvider.cs b/source/AccessTokenValidation/Plumbing/DiscoveryDocumentIssuerSecurityTokenProvider.cs
index 75c7711..901f3a4 100644
--- a/source/AccessTokenValidation/Plumbing/DiscoveryDocumentIssuerSecurityTokenProvider.cs
+++ b/source/AccessTokenValidation/Plumbing/DiscoveryDocumentIssuerSecurityTokenProvider.cs
@@ -33,6 +33,7 @@ internal class DiscoveryDocumentIssuerSecurityTokenProvider : IIssuerSecurityTok
         private readonly ILogger _logger;
         private string _issuer;
         private IEnumerable<SecurityToken> _tokens;
+        private DateTimeOffset _syncAfter = new DateTimeOffset(new DateTime(2001, 1, 1));
 
         public DiscoveryDocumentIssuerSecurityTokenProvider(string discoveryEndpoint, IdentityServerBearerTokenAuthenticationOptions options, ILoggerFactory loggerFactory)
         {
@@ -55,7 +56,7 @@ public DiscoveryDocumentIssuerSecurityTokenProvider(string discoveryEndpoint, Id
             {
                 AutomaticRefreshInterval = options.AutomaticRefreshInterval
             };
-
+            
             if (!options.DelayLoadMetadata)
             {
                 RetrieveMetadata();
@@ -131,6 +132,11 @@ public IEnumerable<SecurityToken> SecurityTokens
 
         private void RetrieveMetadata()
         {
+            if (_syncAfter >= DateTimeOffset.UtcNow)
+            {
+                return;
+            }
+
             _synclock.EnterWriteLock();
             try
             {
@@ -157,6 +163,7 @@ private void RetrieveMetadata()
 
                 _issuer = result.Issuer;
                 _tokens = tokens;
+                _syncAfter = DateTimeOffset.UtcNow + _configurationManager.AutomaticRefreshInterval;
             }
             catch (Exception ex)
             {