Server version check for CSC activation

src/main/java/redis/clients/jedis/Connection.java

@@ -12,6 +12,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.function.Supplier;
 
 import redis.clients.jedis.Protocol.Command;
@@ -41,6 +42,8 @@ public class Connection implements Closeable {
   private boolean broken = false;
   private boolean strValActive;
   private String strVal;
+  protected String server;
+  protected String version;
 
   public Connection() {
     this(Protocol.DEFAULT_HOST, Protocol.DEFAULT_PORT);
@@ -453,12 +456,12 @@ protected void initializeFromClientConfig(final JedisClientConfig config) {
         final RedisCredentialsProvider redisCredentialsProvider = (RedisCredentialsProvider) credentialsProvider;
         try {
           redisCredentialsProvider.prepare();
-          helloOrAuth(protocol, redisCredentialsProvider.get());
+          helloAndAuth(protocol, redisCredentialsProvider.get());
         } finally {
           redisCredentialsProvider.cleanUp();
         }
       } else {
-        helloOrAuth(protocol, credentialsProvider != null ? credentialsProvider.get()
+        helloAndAuth(protocol, credentialsProvider != null ? credentialsProvider.get()
             : new DefaultRedisCredentials(config.getUser(), config.getPassword()));
       }
 
@@ -517,50 +520,56 @@ protected void initializeFromClientConfig(final JedisClientConfig config) {
     }
   }
 
-  private void helloOrAuth(final RedisProtocol protocol, final RedisCredentials credentials) {
-
-    if (credentials == null || credentials.getPassword() == null) {
-      if (protocol != null) {
-        sendCommand(Command.HELLO, encode(protocol.version()));
-        getOne();
+  private void helloAndAuth(final RedisProtocol protocol, final RedisCredentials credentials) {
+    Map<String, Object> helloResult = null;
+    if (protocol != null && credentials != null && credentials.getUser() != null) {
+      byte[] rawPass = encodeToBytes(credentials.getPassword());
+      try {
+        helloResult = hello(encode(protocol.version()), Keyword.AUTH.getRaw(), encode(credentials.getUser()), rawPass);
+      } finally {
+        Arrays.fill(rawPass, (byte) 0); // clear sensitive data
       }
-      return;
+    } else {
+      auth(credentials);
+      helloResult = protocol == null ? null : hello(encode(protocol.version()));
+    }
+    if (helloResult != null) {
+      server = (String) helloResult.get("server");
+      version = (String) helloResult.get("version");
     }
 
-    // Source: https://stackoverflow.com/a/9670279/4021802
-    ByteBuffer passBuf = Protocol.CHARSET.encode(CharBuffer.wrap(credentials.getPassword()));
-    byte[] rawPass = Arrays.copyOfRange(passBuf.array(), passBuf.position(), passBuf.limit());
-    Arrays.fill(passBuf.array(), (byte) 0); // clear sensitive data
+    // clearing 'char[] credentials.getPassword()' should be
+    // handled in RedisCredentialsProvider.cleanUp()
+  }
 
+  private void auth(RedisCredentials credentials) {
+    if (credentials == null || credentials.getPassword() == null) {
+      return;
+    }
+    byte[] rawPass = encodeToBytes(credentials.getPassword());
     try {
-      /// actual HELLO or AUTH -->
-      if (protocol != null) {
-        if (credentials.getUser() != null) {
-          sendCommand(Command.HELLO, encode(protocol.version()),
-              Keyword.AUTH.getRaw(), encode(credentials.getUser()), rawPass);
-          getOne(); // Map
-        } else {
-          sendCommand(Command.AUTH, rawPass);
-          getStatusCodeReply(); // OK
-          sendCommand(Command.HELLO, encode(protocol.version()));
-          getOne(); // Map
-        }
-      } else { // protocol == null
-        if (credentials.getUser() != null) {
-          sendCommand(Command.AUTH, encode(credentials.getUser()), rawPass);
-        } else {
-          sendCommand(Command.AUTH, rawPass);
-        }
-        getStatusCodeReply(); // OK
+      if (credentials.getUser() == null) {
+        sendCommand(Command.AUTH, rawPass);
+      } else {
+        sendCommand(Command.AUTH, encode(credentials.getUser()), rawPass);
       }
-      /// <-- actual HELLO or AUTH
     } finally {
-
       Arrays.fill(rawPass, (byte) 0); // clear sensitive data
     }
+    getStatusCodeReply();
+  }
 
-    // clearing 'char[] credentials.getPassword()' should be
-    // handled in RedisCredentialsProvider.cleanUp()
+  protected Map<String, Object> hello(byte[]... args) {
+    sendCommand(Command.HELLO, args);
+    return BuilderFactory.ENCODED_OBJECT_MAP.build(getOne());
+  }
+
+  protected byte[] encodeToBytes(char[] chars) {
+    // Source: https://stackoverflow.com/a/9670279/4021802
+    ByteBuffer passBuf = Protocol.CHARSET.encode(CharBuffer.wrap(chars));
+    byte[] rawPass = Arrays.copyOfRange(passBuf.array(), passBuf.position(), passBuf.limit());
+    Arrays.fill(passBuf.array(), (byte) 0); // clear sensitive data
+    return rawPass;
   }
 
   public String select(final int index) {

src/main/java/redis/clients/jedis/csc/AbstractCache.java

@@ -193,6 +193,10 @@ public CacheStats getAndResetStats() {
     return result;
   }
 
+  @Override
+  public boolean compatibilityMode() {
+    return false;
+  }
   // End of Cache interface methods
 
   // abstract methods to be implemented by the concrete classes

src/main/java/redis/clients/jedis/csc/Cache.java

@@ -105,4 +105,9 @@ public interface Cache {
      * @return The statistics of the cache
      */
     CacheStats getAndResetStats();
+
+    /**
+     * @return The compatibility of cache against different Redis versions
+     */
+    boolean compatibilityMode();
 }

src/main/java/redis/clients/jedis/csc/CacheConnection.java

@@ -16,13 +16,22 @@ public class CacheConnection extends Connection {
 
   private final Cache cache;
   private ReentrantLock lock;
+  private static final String REDIS = "redis";
+  private static final String MIN_REDIS_VERSION = "7.4";
 
   public CacheConnection(final JedisSocketFactory socketFactory, JedisClientConfig clientConfig, Cache cache) {
     super(socketFactory, clientConfig);
 
     if (protocol != RedisProtocol.RESP3) {
       throw new JedisException("Client side caching is only supported with RESP3.");
     }
+    if (!cache.compatibilityMode()) {
+      RedisVersion current = new RedisVersion(version);
+      RedisVersion required = new RedisVersion(MIN_REDIS_VERSION);
+      if (!REDIS.equals(server) || current.compareTo(required) < 0) {
+        throw new JedisException(String.format("Client side caching is only supported with 'Redis %s' or later.", MIN_REDIS_VERSION));
+      }
+    }
     this.cache = Objects.requireNonNull(cache);
     initializeClientSideCache();
   }

src/main/java/redis/clients/jedis/csc/RedisVersion.java

@@ -0,0 +1,41 @@
+package redis.clients.jedis.csc;
+
+import java.util.Arrays;
+
+class RedisVersion implements Comparable<RedisVersion> {
+
+    private String version;
+    private Integer[] numbers;
+
+    public RedisVersion(String version) {
+        if (version == null) throw new IllegalArgumentException("Version can not be null");
+        this.version = version;
+        this.numbers = Arrays.stream(version.split("\\.")).map(n -> Integer.parseInt(n)).toArray(Integer[]::new);
+    }
+
+    @Override
+    public int compareTo(RedisVersion other) {
+        int max = Math.max(this.numbers.length, other.numbers.length);
+        for (int i = 0; i < max; i++) {
+            int thisNumber = this.numbers.length > i ? this.numbers[i]:0;
+            int otherNumber = other.numbers.length > i ? other.numbers[i]:0;
+            if (thisNumber < otherNumber) return -1;
+            if (thisNumber > otherNumber) return 1;
+        }
+        return 0;
+    }
+
+    @Override
+    public String toString() {
+        return this.version;
+    }
+
+    @Override
+    public boolean equals(Object that) {
+        if (this == that) return true;
+        if (that == null) return false;
+        if (this.getClass() != that.getClass()) return false;
+        return this.compareTo((RedisVersion) that) == 0;
+    }
+
+}

src/test/java/redis/clients/jedis/csc/VersionTest.java

@@ -0,0 +1,30 @@
+package redis.clients.jedis.csc;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class VersionTest {
+
+    @Test
+    public void compareSameVersions() {
+        RedisVersion a = new RedisVersion("5.2.4");
+        RedisVersion b = new RedisVersion("5.2.4");
+        assertEquals(a, b);
+
+        RedisVersion c = new RedisVersion("5.2.0.0");
+        RedisVersion d = new RedisVersion("5.2");
+        assertEquals(a, b);
+    }
+
+    @Test
+    public void compareDifferentVersions() {
+        RedisVersion a = new RedisVersion("5.2.4");
+        RedisVersion b = new RedisVersion("5.1.4");
+        assertEquals(1, a.compareTo(b));
+
+        RedisVersion c = new RedisVersion("5.2.4");
+        RedisVersion d = new RedisVersion("5.2.5");
+        assertEquals(-1, c.compareTo(d));
+    }
+}