From 8cdbef594e717639653ee2a995a5fded05436f75 Mon Sep 17 00:00:00 2001
From: Bill Smith <wsmith@unicon.net>
Date: Fri, 7 Sep 2018 13:14:59 -0700
Subject: [PATCH] [SHIBUI-570]

Added simple caching of fetchMetdata and unmarshallMetadata.
---
 .../MetadataResolversController.java          |  2 +
 ...penSamlFileBackedHTTPMetadataResolver.java | 41 +++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/MetadataResolversController.java b/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/MetadataResolversController.java
index 4d7d7aaac..2b4b90d65 100644
--- a/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/MetadataResolversController.java
+++ b/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/controller/MetadataResolversController.java
@@ -118,6 +118,8 @@ public ResponseEntity<?> create(@RequestBody MetadataResolver newResolver) throw
         MetadataResolver persistedResolver = resolverRepository.save(newResolver);
         positionOrderContainerService.appendPositionOrderForNew(persistedResolver);
 
+        //TODO: currently, the update call might explode, but the save works.. in which case, the UI never gets
+        // an valid response. This operation is not atomic. Should we return an error here?
         updateChainingMetadataResolver(persistedResolver);
 
         return ResponseEntity.created(getResourceUriFor(persistedResolver)).body(persistedResolver);
diff --git a/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/domain/resolvers/opensaml/OpenSamlFileBackedHTTPMetadataResolver.java b/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/domain/resolvers/opensaml/OpenSamlFileBackedHTTPMetadataResolver.java
index 5f4c10905..e74bff535 100644
--- a/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/domain/resolvers/opensaml/OpenSamlFileBackedHTTPMetadataResolver.java
+++ b/backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/domain/resolvers/opensaml/OpenSamlFileBackedHTTPMetadataResolver.java
@@ -8,21 +8,35 @@
 import org.apache.http.impl.client.HttpClients;
 import org.apache.lucene.index.IndexWriter;
 import org.joda.time.DateTime;
+import org.opensaml.core.xml.XMLObject;
+import org.opensaml.core.xml.io.UnmarshallingException;
 import org.opensaml.saml.metadata.resolver.impl.FileBackedHTTPMetadataResolver;
 
+import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import java.io.InputStream;
+import java.time.Instant;
+
 import static edu.internet2.tier.shibboleth.admin.util.DurationUtility.toMillis;
 
 /**
  * @author Bill Smith (wsmith@unicon.net)
  */
 public class OpenSamlFileBackedHTTPMetadataResolver extends FileBackedHTTPMetadataResolver {
+
+    private static final long MILLISECONDS_IN_ONE_SECOND = 1000;
+
     private IndexWriter indexWriter;
     private FileBackedHttpMetadataResolver sourceResolver;
 
     private OpenSamlMetadataResolverDelegate delegate;
 
+    private byte[] cachedMetadataBytes;
+    private Instant metadataLastFetchedAt;
+    boolean shouldRefreshMetadata;
+    XMLObject cachedMetadata;
+
     public OpenSamlFileBackedHTTPMetadataResolver(ParserPool parserPool,
                                                   IndexWriter indexWriter,
                                                   FileBackedHttpMetadataResolver sourceResolver) throws ResolverException {
@@ -67,4 +81,31 @@ protected void initMetadataResolver() throws ComponentInitializationException {
                                                        this.sourceResolver.getResourceId(),
                                                        indexWriter);
     }
+
+    @Override
+    protected byte[] fetchMetadata() throws ResolverException {
+        if (metadataLastFetchedAt == null || shouldRefreshMetadata()) {
+            this.cachedMetadataBytes = super.fetchMetadata();
+            this.metadataLastFetchedAt = Instant.now();
+        }
+        return cachedMetadataBytes;
+    }
+
+    private boolean shouldRefreshMetadata() {
+        if ((Instant.now().getEpochSecond() - metadataLastFetchedAt.getEpochSecond()) > (this.getMinRefreshDelay() / MILLISECONDS_IN_ONE_SECOND)) {
+            shouldRefreshMetadata = true;
+        }
+        return shouldRefreshMetadata;
+    }
+
+    @Override
+    protected XMLObject unmarshallMetadata(@Nonnull final InputStream metadataInput)
+            throws UnmarshallingException {
+        //TODO: This should probably be based on something other than minRefreshDelay
+        if (cachedMetadata == null || shouldRefreshMetadata) {
+            this.cachedMetadata = super.unmarshallMetadata(metadataInput);
+            this.shouldRefreshMetadata = false;
+        }
+        return this.cachedMetadata;
+    }
 }