Better truncation of sensitive values

Author: devgianlu

common/src/main/java/xyz/gianlu/librespot/common/Utils.java

@@ -49,6 +49,17 @@ public static String randomString(@NotNull Random random, int length) {
         return new String(chars);
     }
 
+    @NotNull
+    public static String truncateMiddle(@NotNull String str, int length) {
+        if (length <= 1) throw new IllegalStateException();
+
+        int first = length / 2;
+        String result = str.substring(0, first);
+        result += "...";
+        result += str.substring(str.length() - (length - first));
+        return result;
+    }
+
     @NotNull
     public static String readLine(@NotNull InputStream in) throws IOException {
         ByteArrayOutputStream buffer = new ByteArrayOutputStream();

core/src/main/java/xyz/gianlu/librespot/connectstate/DeviceStateHandler.java

@@ -16,6 +16,7 @@
 import xyz.gianlu.librespot.Version;
 import xyz.gianlu.librespot.common.AsyncWorker;
 import xyz.gianlu.librespot.common.ProtoUtils;
+import xyz.gianlu.librespot.common.Utils;
 import xyz.gianlu.librespot.core.Session;
 import xyz.gianlu.librespot.core.TimeProvider;
 import xyz.gianlu.librespot.dealer.DealerClient;
@@ -245,11 +246,11 @@ private void putConnectState(@NotNull Connect.PutStateRequest req) {
         try {
             session.api().putConnectState(connectionId, req);
             if (LOGGER.getLevel().isLessSpecificThan(Level.TRACE)) {
-                LOGGER.info("Put state. {ts: {}, connId: {}[truncated], reason: {}, request: {}}", req.getClientSideTimestamp(),
-                        connectionId.substring(0, 6), req.getPutStateReason(), TextFormat.shortDebugString(putState));
+                LOGGER.info("Put state. {ts: {}, connId: {}, reason: {}, request: {}}", req.getClientSideTimestamp(),
+                        Utils.truncateMiddle(connectionId, 10), req.getPutStateReason(), TextFormat.shortDebugString(putState));
             } else {
-                LOGGER.info("Put state. {ts: {}, connId: {}[truncated], reason: {}}", req.getClientSideTimestamp(),
-                        connectionId.substring(0, 6), req.getPutStateReason());
+                LOGGER.info("Put state. {ts: {}, connId: {}, reason: {}}", req.getClientSideTimestamp(),
+                        Utils.truncateMiddle(connectionId, 10), req.getPutStateReason());
             }
         } catch (IOException | MercuryClient.MercuryException ex) {
             LOGGER.error("Failed updating state.", ex);

core/src/main/java/xyz/gianlu/librespot/core/TokenProvider.java

@@ -5,6 +5,7 @@
 import org.apache.logging.log4j.Logger;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import xyz.gianlu.librespot.common.Utils;
 import xyz.gianlu.librespot.mercury.MercuryClient;
 import xyz.gianlu.librespot.mercury.MercuryRequests;
 
@@ -86,8 +87,8 @@ public boolean expired() {
         public String toString() {
             return "StoredToken{" +
                     "expiresIn=" + expiresIn +
-                    ", accessToken='" + accessToken.substring(0, 10) + "[truncated]'" +
-                    ", scopes=" + Arrays.toString(scopes) +
+                    ", accessToken='" + Utils.truncateMiddle(accessToken, 12) +
+                    "', scopes=" + Arrays.toString(scopes) +
                     ", timestamp=" + timestamp +
                     '}';
         }