From cc3cab9c88737c05a60c1a5946d62b6564020f7a Mon Sep 17 00:00:00 2001
From: Ehren Kret <ehren@signal.org>
Date: Wed, 21 Jun 2023 16:08:46 -0500
Subject: [PATCH] Add server time to remote config fetch

Enable clients to very roughly adjust some actions for clock skew by
providing current server time in the remote config fetch.
---
 .../controllers/RemoteConfigController.java         |  3 ++-
 .../entities/UserRemoteConfigList.java              | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/RemoteConfigController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/RemoteConfigController.java
index 8cde735de..d6738e631 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/RemoteConfigController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/RemoteConfigController.java
@@ -15,6 +15,7 @@ import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.time.Clock;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -91,7 +92,7 @@ public class RemoteConfigController {
             config.getUuids());
         return new UserRemoteConfig(config.getName(), inBucket,
             inBucket ? config.getValue() : config.getDefaultValue());
-      }), globalConfigStream).collect(Collectors.toList()));
+      }), globalConfigStream).collect(Collectors.toList()), Clock.systemUTC().instant());
     } catch (NoSuchAlgorithmException e) {
       throw new AssertionError(e);
     }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/entities/UserRemoteConfigList.java b/service/src/main/java/org/whispersystems/textsecuregcm/entities/UserRemoteConfigList.java
index 6fba91364..18a90d57d 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/entities/UserRemoteConfigList.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/entities/UserRemoteConfigList.java
@@ -5,8 +5,10 @@
 
 package org.whispersystems.textsecuregcm.entities;
 
+import com.fasterxml.jackson.annotation.JsonFormat;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
+import java.time.Instant;
 import java.util.List;
 
 public class UserRemoteConfigList {
@@ -14,13 +16,22 @@ public class UserRemoteConfigList {
   @JsonProperty
   private List<UserRemoteConfig> config;
 
+  @JsonProperty
+  @JsonFormat(shape = JsonFormat.Shape.NUMBER_INT)
+  private Instant serverEpochTime;
+
   public UserRemoteConfigList() {}
 
-  public UserRemoteConfigList(List<UserRemoteConfig> config) {
+  public UserRemoteConfigList(List<UserRemoteConfig> config, Instant serverEpochTime) {
     this.config = config;
+    this.serverEpochTime = serverEpochTime;
   }
 
   public List<UserRemoteConfig> getConfig() {
     return config;
   }
+
+  public Instant getServerEpochTime() {
+    return serverEpochTime;
+  }
 }