ETags on resources

An etag should be generated (by Champ) when creating
a resource (edge or vertex). The Champ microservice should return
this etag in the response header. Gizmo should also return the etag
in it's response header (Gizmo will receive the etag from Champ).

Issue-ID: AAI-1196

Change-Id: Ie16f871eccbceeccde037e73e0de0d96eeba18bd
Signed-off-by: Sotiropoulos, Ioannis (is948x) <Ioannis.Sotiropoulos@amdocs.com>

4 files changed, 184 insertions, 16 deletions

diff --git a/src/main/java/org/onap/crud/util/CrudServiceConstants.java b/src/main/java/org/onap/crud/util/CrudServiceConstants.java
index 3a02852..ae5b464 100644
--- a/src/main/java/org/onap/crud/util/CrudServiceConstants.java
+++ b/src/main/java/org/onap/crud/util/CrudServiceConstants.java
@@ -39,4 +39,5 @@ public class CrudServiceConstants {
   public static final String CRD_COLLECTION_PROPERTIES_KEY = "crud.collection.properties.key";
   public static final String CRD_RESERVED_VERSION = "_reserved_version";
   public static final String CRD_RESERVED_NODE_TYPE = "_reserved_aai-type";
+  public static final String CRD_HEADER_ETAG = "etag";
 }
diff --git a/src/main/java/org/onap/crud/util/CrudServiceUtil.java b/src/main/java/org/onap/crud/util/CrudServiceUtil.java
index 6c251bc..6b5cdcd 100644
--- a/src/main/java/org/onap/crud/util/CrudServiceUtil.java
+++ b/src/main/java/org/onap/crud/util/CrudServiceUtil.java
@@ -20,6 +20,15 @@
  */
 package org.onap.crud.util;
 
+import java.util.AbstractMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import javax.ws.rs.core.EntityTag;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.core.Response.Status;
 import org.onap.aai.db.props.AAIProperties;
 import org.onap.crud.exception.CrudException;
 import org.onap.schema.OxmModelLoader;
@@ -29,15 +38,6 @@ import com.google.gson.Gson;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonPrimitive;
 
-import java.util.AbstractMap;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
-import java.util.Map.Entry;
-
-import javax.ws.rs.core.HttpHeaders;
-import javax.ws.rs.core.Response.Status;
-
 public class CrudServiceUtil {
 
   private static Gson gson = new Gson();
@@ -54,13 +54,13 @@ public class CrudServiceUtil {
       } else if (clazz.isAssignableFrom(Double.class)) {
         return Double.parseDouble(value);
       } else if (clazz.isAssignableFrom(Boolean.class)) {
-		  
+
 		// If the value is an IN/OUT direction, this gets seen as a boolean, so
         // check for that first.
         if (value.equals("OUT") || value.equals("IN")) {
           return value;
         }
-		
+
         if (!value.equals("true") && !value.equals("false")) {
           throw new CrudException("Invalid propertry value: " + value, Status.BAD_REQUEST);
         }
@@ -82,7 +82,7 @@ public class CrudServiceUtil {
       throw new CrudException(e);
     }
   }
-  
+
   /**
    * This method will merge header property from app id in request payload if not already populated
    * @param propertiesFromRequest
@@ -104,12 +104,12 @@ public class CrudServiceUtil {
     
     if(!propertyKeys.contains(AAIProperties.LAST_MOD_SOURCE_OF_TRUTH)) {
         properties.add(new AbstractMap.SimpleEntry<String, JsonElement>(AAIProperties.LAST_MOD_SOURCE_OF_TRUTH,
-            (JsonElement)(new JsonPrimitive(sourceOfTruth))));
+            (new JsonPrimitive(sourceOfTruth))));
     }
    
     if(isAdd && !propertyKeys.contains(AAIProperties.SOURCE_OF_TRUTH)) {
         properties.add(new AbstractMap.SimpleEntry<String, JsonElement>(AAIProperties.SOURCE_OF_TRUTH,
-            (JsonElement)(new JsonPrimitive(sourceOfTruth))));
+            (new JsonPrimitive(sourceOfTruth))));
     }
 
     Object[] propArray = properties.toArray();
@@ -117,7 +117,7 @@ public class CrudServiceUtil {
     sb.append("{");
     boolean first=true;
     for(int i=0; i<propArray.length; i++) {
-      
+
       Map.Entry<String, JsonElement> entry = (Entry<String, JsonElement>) propArray[i];
       if(!first) {
         sb.append(",");
@@ -126,7 +126,17 @@ public class CrudServiceUtil {
       first=false;
     }
     sb.append("}");
-    
+
     return gson.fromJson(sb.toString(), JsonElement.class);
   }
+
+  public static EntityTag getETagFromHeader(MultivaluedMap<String, String> headers) {
+    EntityTag entityTag = null;
+    if (headers != null && headers.containsKey(CrudServiceConstants.CRD_HEADER_ETAG)) {
+      String value = headers.getFirst(CrudServiceConstants.CRD_HEADER_ETAG);
+      entityTag = new EntityTag(value.replace("\"", ""));
+    }
+    return entityTag;
+  }
+
 }
diff --git a/src/main/java/org/onap/crud/util/HashGenerator.java b/src/main/java/org/onap/crud/util/HashGenerator.java
new file mode 100644
index 0000000..02558fa
--- /dev/null
+++ b/src/main/java/org/onap/crud/util/HashGenerator.java
@@ -0,0 +1,65 @@
+/**
+ * ============LICENSE_START=======================================================
+ * org.onap.aai
+ * ================================================================================
+ * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright © 2017-2018 Amdocs
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.crud.util;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectOutput;
+import java.io.ObjectOutputStream;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+/**
+ * Generates a sha 256 hash
+ */
+public class HashGenerator {
+
+    private MessageDigest messageDigest;
+
+    public HashGenerator() throws NoSuchAlgorithmException {
+        this.messageDigest = MessageDigest.getInstance("SHA-256");
+    }
+
+    /**
+     * Generates a SHA 256 hash as a hexadecimal string for the inputs.
+     * Calls toString on the input objects to convert into a byte stream.
+     * @param values
+     * @return SHA 256 hash of the inputs as a hexadecimal string.
+     * @throws IOException
+     */
+    public String generateSHA256AsHex(Object... values) throws IOException {
+        byte[] bytes = convertToBytes(values);
+        byte[] digest = messageDigest.digest(bytes);
+        StringBuilder result = new StringBuilder();
+        for (byte byt : digest) result.append(Integer.toString((byt & 0xff) + 0x100, 16).substring(1));
+        return result.toString();
+    }
+
+    private byte[] convertToBytes(Object... values) throws IOException {
+        try (ByteArrayOutputStream bos = new ByteArrayOutputStream();
+             ObjectOutput out = new ObjectOutputStream(bos)) {
+            for (Object object : values) {
+                out.writeObject(object.toString());
+            }
+            return bos.toByteArray();
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/src/main/java/org/onap/crud/util/etag/EtagGenerator.java b/src/main/java/org/onap/crud/util/etag/EtagGenerator.java
new file mode 100644
index 0000000..b288b78
--- /dev/null
+++ b/src/main/java/org/onap/crud/util/etag/EtagGenerator.java
@@ -0,0 +1,92 @@
+/**
+ * ============LICENSE_START=======================================================
+ * org.onap.aai
+ * ================================================================================
+ * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
+ * Copyright © 2017-2018 Amdocs
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+package org.onap.crud.util.etag;
+
+import java.io.IOException;
+import java.security.NoSuchAlgorithmException;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import org.onap.crud.event.GraphEventEdge;
+import org.onap.crud.event.GraphEventVertex;
+import org.onap.crud.util.HashGenerator;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+
+/**
+ * Computes hash for GraphEventVertex and GraphEventEdge
+ */
+public class EtagGenerator {
+
+    private static final String AAI_LAST_MOD_TS = "aai-last-mod-ts";
+    private final HashGenerator hashGenerator;
+
+    public EtagGenerator() throws NoSuchAlgorithmException {
+        this.hashGenerator = new HashGenerator();
+    }
+
+    /**
+     * Takes in the GraphEventVertex for which the hash is to be computed.
+     * @param GraphEventVertex
+     * @return hash for the GraphEventVertex
+     * @throws IOException
+     */
+    public String computeHashForVertex(GraphEventVertex graphEventVertex) throws IOException {
+        return hashGenerator.generateSHA256AsHex(graphEventVertex.getId(), graphEventVertex.getType(), convertPropertiesToMap(graphEventVertex.getProperties()));
+    }
+
+    /**
+     * Takes in the GraphEventEdge for which the hash is to be computed.
+     * @param GraphEventEdge
+     * @return hash for the GraphEventEdge
+     * @throws IOException
+     */
+    public String computeHashForEdge(GraphEventEdge graphEventEdge) throws IOException {
+        return hashGenerator.generateSHA256AsHex(graphEventEdge.getId(), graphEventEdge.getType(),
+                convertPropertiesToMap(graphEventEdge.getProperties()),
+                computeHashForVertex(graphEventEdge.getSource()), computeHashForVertex(graphEventEdge.getTarget()));
+    }
+
+    private Map<String, Object> convertPropertiesToMap(JsonElement properties) {
+        Map<String, Object> propertiesMap = new HashMap<>();
+        if (null != properties) {
+            JsonObject propsObject = properties.getAsJsonObject();
+            for (Entry<String, JsonElement> props : propsObject.entrySet()) {
+                String key = props.getKey();
+                String value = props.getValue().getAsString();
+                propertiesMap.put(key, value);
+            }
+        }
+        return filterAndSortProperties(propertiesMap);
+    }
+
+    private Map<String, Object> filterAndSortProperties(Map<String, Object> properties) {
+        return properties
+                .entrySet()
+                .stream()
+                .filter(x -> !x.getKey().equals(AAI_LAST_MOD_TS))
+                .sorted((x, y) -> x.getKey().compareTo(y.getKey()))
+                .collect(LinkedHashMap::new,
+                        (m, e) -> m.put(e.getKey(), e.getValue()),
+                        Map::putAll);
+    }
+}
\ No newline at end of file