Fix Endian

sdk/spring/spring-cloud-azure-feature-management/src/main/java/com/azure/spring/cloud/feature/management/filters/TargetingFilter.java

@@ -2,21 +2,17 @@
 // Licensed under the MIT License.
 package com.azure.spring.cloud.feature.management.filters;
 
-import java.nio.ByteBuffer;
-import java.nio.charset.Charset;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
-import com.azure.spring.cloud.feature.management.implementation.FeatureFilterUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.util.StringUtils;
 
+import com.azure.spring.cloud.feature.management.implementation.FeatureFilterUtils;
 import com.azure.spring.cloud.feature.management.implementation.targeting.Audience;
 import com.azure.spring.cloud.feature.management.implementation.targeting.Exclusion;
 import com.azure.spring.cloud.feature.management.implementation.targeting.GroupRollout;
@@ -133,8 +129,10 @@ public boolean evaluate(FeatureFilterEvaluationContext context) {
 
         Audience audience;
         String exclusionValue = FeatureFilterUtils.getKeyCase(parameters, EXCLUSION_CAMEL);
-        String exclusionUserValue = FeatureFilterUtils.getKeyCase((Map<String, Object>) parameters.get(exclusionValue), "Users");
-        String exclusionGroupsValue = FeatureFilterUtils.getKeyCase((Map<String, Object>) parameters.get(exclusionValue), "Groups");
+        String exclusionUserValue = FeatureFilterUtils.getKeyCase((Map<String, Object>) parameters.get(exclusionValue),
+            "Users");
+        String exclusionGroupsValue = FeatureFilterUtils
+            .getKeyCase((Map<String, Object>) parameters.get(exclusionValue), "Groups");
 
         if (((Map<String, Object>) parameters.getOrDefault(exclusionValue, new HashMap<>()))
             .get(exclusionUserValue) instanceof List) {
@@ -227,35 +225,8 @@ private boolean validateTargetingContext(TargetingFilterContext targetingContext
         return (!hasUserDefined && !(hasGroupsDefined && hasAtLeastOneGroup));
     }
 
-    /**
-     * Computes the percentage that the contextId falls into.
-     *
-     * @param contextId Id of the context being targeted
-     * @return the bucket value of the context id
-     * @throws TargetingException Unable to create hash of target context
-     */
-    protected double isTargetedPercentage(String contextId) {
-        byte[] hash = null;
-
-        try {
-            MessageDigest digest = MessageDigest.getInstance("SHA-256");
-            hash = digest.digest(contextId.getBytes(Charset.defaultCharset()));
-        } catch (NoSuchAlgorithmException e) {
-            throw new TargetingException("Unable to find SHA-256 for targeting.", e);
-        }
-
-        if (hash == null) {
-            throw new TargetingException("Unable to create Targeting Hash for " + contextId);
-        }
-
-        ByteBuffer wrapped = ByteBuffer.wrap(hash);
-        int contextMarker = Math.abs(wrapped.getInt());
-
-        return (contextMarker / (double) Integer.MAX_VALUE) * 100;
-    }
-
     private boolean isTargeted(String contextId, double percentage) {
-        return isTargetedPercentage(contextId) < percentage;
+        return FeatureFilterUtils.isTargetedPercentage(contextId) < percentage;
     }
 
     /**

sdk/spring/spring-cloud-azure-feature-management/src/main/java/com/azure/spring/cloud/feature/management/implementation/FeatureFilterUtils.java

@@ -3,11 +3,16 @@
 
 package com.azure.spring.cloud.feature.management.implementation;
 
+import java.math.BigInteger;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.util.Collection;
 import java.util.Map;
 
 import org.springframework.util.StringUtils;
 
+import com.azure.spring.cloud.feature.management.models.TargetingException;
+
 public class FeatureFilterUtils {
 
     /**
@@ -34,4 +39,43 @@ public static String getKeyCase(Map<String, Object> parameters, String key) {
         return StringUtils.uncapitalize(key);
     }
 
+    /**
+     * Computes the percentage that the contextId falls into.
+     * 
+     * @param contextId Id of the context being targeted
+     * @return the bucket value of the context id
+     * @throws TargetingException Unable to create hash of target context
+     */
+    public static double isTargetedPercentage(String contextId) {
+        byte[] hash = null;
+        if (contextId == null) {
+            contextId = "\n";
+        }
+
+        try {
+            MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            hash = digest.digest(contextId.getBytes());
+
+        } catch (NoSuchAlgorithmException e) {
+            throw new TargetingException("Unable to find SHA-256 for targeting.", e);
+        }
+
+        if (hash == null) {
+            throw new TargetingException("Unable to create Targeting Hash for " + contextId);
+        }
+
+        BigInteger bi = bigEndianToLittleEndian(hash);
+
+        return (bi.longValue() / (Math.pow(2, 32) - 1)) * 100;
+    }
+
+    public static BigInteger bigEndianToLittleEndian(byte[] bigEndian) {
+        byte[] reversedBytes = new byte[4];
+        for (int i = 0; i < 4; i++) {
+            reversedBytes[i] = bigEndian[3 - i];
+        }
+
+        return new BigInteger(1, reversedBytes);
+    }
+
 }

sdk/spring/spring-cloud-azure-feature-management/src/test/java/com/azure/spring/cloud/feature/management/filters/TargetingFilterTest.java

@@ -218,7 +218,7 @@ public void targetedGroupFiftyPass() {
 
         TargetingFilter filter = new TargetingFilter(new TargetingFilterTestContextAccessor("Jane", targetedGroups));
 
-        assertTrue(filter.evaluate(context));
+        assertFalse(filter.evaluate(context));
     }
 
     @Test
@@ -246,7 +246,7 @@ public void targetedGroupFiftyFalse() {
 
         TargetingFilter filter = new TargetingFilter(new TargetingFilterTestContextAccessor("Doe", targetedGroups));
 
-        assertFalse(filter.evaluate(context));
+        assertTrue(filter.evaluate(context));
     }
 
     @Test

sdk/spring/spring-cloud-azure-feature-management/src/test/java/com/azure/spring/cloud/feature/management/implemenation/TargetingFilterUtilsTest.java

@@ -0,0 +1,20 @@
+package com.azure.spring.cloud.feature.management.implemenation;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+import com.azure.spring.cloud.feature.management.implementation.FeatureFilterUtils;
+
+public class TargetingFilterUtilsTest {
+
+    @Test
+    public void isTargetedPercentageTest() {        
+        assertEquals(FeatureFilterUtils.isTargetedPercentage(null), 9.875071074318855);        
+        assertEquals(FeatureFilterUtils.isTargetedPercentage(""), 26.0813765987012);        
+        assertEquals(FeatureFilterUtils.isTargetedPercentage("Alice"), 38.306839656621875);        
+        assertEquals(FeatureFilterUtils.isTargetedPercentage("Quinn\nDeb"), 38.306839656621875);        
+        assertEquals(FeatureFilterUtils.isTargetedPercentage("\nProd"), 79.98622464481421);
+    }
+
+}