Switch from AsyncHttpClient to JDK HttpClient

AsyncHttpClient is not well-maintained and is unlikely to survive the Netty 5 migration. Switch to the JDK's built-in HttpClient which has a much better chance of being maintained.

proxy/build.gradle

@@ -69,8 +69,6 @@ dependencies {
     implementation(platform("net.kyori:adventure-bom:${adventureVersion}"))
     implementation("net.kyori:adventure-nbt")
 
-    implementation 'org.asynchttpclient:async-http-client:2.12.3'
-
     implementation 'com.spotify:completable-futures:0.3.5'
 
     implementation 'com.electronwill.night-config:toml:3.6.4'

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -68,6 +68,7 @@ import io.netty.channel.ChannelInitializer;
 import io.netty.channel.EventLoopGroup;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.net.http.HttpClient;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -100,7 +101,6 @@ import net.kyori.adventure.translation.TranslationRegistry;
 import net.kyori.adventure.util.UTF8ResourceBundleControl;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.asynchttpclient.AsyncHttpClient;
 import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 import org.checkerframework.checker.nullness.qual.NonNull;
@@ -546,7 +546,7 @@ public class VelocityServer implements ProxyServer, ForwardingAudience {
     shutdown(true);
   }
 
-  public AsyncHttpClient getAsyncHttpClient() {
+  public HttpClient getAsyncHttpClient() {
     return cm.getHttpClient();
   }
 

proxy/src/main/java/com/velocitypowered/proxy/command/builtin/VelocityCommand.java

@@ -21,7 +21,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 
 import com.google.common.collect.ImmutableSet;
-import com.google.common.util.concurrent.MoreExecutors;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParseException;
@@ -37,15 +36,17 @@ import com.velocitypowered.api.util.ProxyVersion;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.util.InformationUtils;
 
-import java.net.ConnectException;
-import java.net.UnknownHostException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpResponse.BodyHandlers;
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.concurrent.ExecutionException;
 import java.util.stream.Collectors;
 
 import net.kyori.adventure.identity.Identity;
@@ -59,10 +60,6 @@ import net.kyori.adventure.text.format.TextColor;
 import net.kyori.adventure.text.format.TextDecoration;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.asynchttpclient.AsyncHttpClient;
-import org.asynchttpclient.BoundRequestBuilder;
-import org.asynchttpclient.ListenableFuture;
-import org.asynchttpclient.Response;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
 public class VelocityCommand implements SimpleCommand {
@@ -380,92 +377,72 @@ public class VelocityCommand implements SimpleCommand {
       dump.add("plugins", InformationUtils.collectPluginInfo(server));
 
       source.sendMessage(Component.text().content("Uploading gathered information...").build());
-      AsyncHttpClient httpClient = ((VelocityServer) server).getAsyncHttpClient();
+      HttpClient httpClient = ((VelocityServer) server).getAsyncHttpClient();
 
-      BoundRequestBuilder request =
-              httpClient.preparePost("https://dump.velocitypowered.com/documents");
-      request.setHeader("Content-Type", "text/plain");
-      request.addHeader("User-Agent", server.getVersion().getName() + "/"
-              + server.getVersion().getVersion());
-      request.setBody(
-              InformationUtils.toHumanReadableString(dump).getBytes(StandardCharsets.UTF_8));
+      httpClient.sendAsync(
+          HttpRequest.newBuilder()
+              .uri(URI.create("https://dump.velocitypowered.com/documents"))
+              .POST(BodyPublishers.ofString(
+                  InformationUtils.toHumanReadableString(dump), StandardCharsets.UTF_8
+              ))
+              .header("Content-Type", "text/plain")
+              .header("User-Agent", server.getVersion().getName() + "/"
+                  + server.getVersion().getVersion())
+              .build(),
+          BodyHandlers.ofString()
+      ).thenAccept(response -> {
+        if (response.statusCode() != 200) {
+          source.sendMessage(Component.text()
+              .content("An error occurred while communicating with the Velocity servers. "
+                  + "The servers may be temporarily unavailable or there is an issue "
+                  + "with your network settings. You can find more information in the "
+                  + "log or console of your Velocity server.")
+              .color(NamedTextColor.RED).build());
+          logger.error("Invalid status code while POST-ing Velocity dump: "
+              + response.statusCode());
+          logger.error("Headers: \n--------------BEGIN HEADERS--------------\n"
+              + response.headers().toString()
+              + "\n---------------END HEADERS---------------");
+          return;
+        }
 
-      ListenableFuture<Response> future = request.execute();
-      future.addListener(() -> {
         try {
-          Response response = future.get();
-          if (response.getStatusCode() != 200) {
-            source.sendMessage(Component.text()
-                    .content("An error occurred while communicating with the Velocity servers. "
-                            + "The servers may be temporarily unavailable or there is an issue "
-                            + "with your network settings. You can find more information in the "
-                            + "log or console of your Velocity server.")
-                    .color(NamedTextColor.RED).build());
-            logger.error("Invalid status code while POST-ing Velocity dump: "
-                    + response.getStatusCode());
-            logger.error("Headers: \n--------------BEGIN HEADERS--------------\n"
-                    + response.getHeaders().toString()
-                    + "\n---------------END HEADERS---------------");
-            return;
-          }
-          JsonObject key = InformationUtils.parseString(
-                  response.getResponseBody(StandardCharsets.UTF_8));
+          JsonObject key = InformationUtils.parseString(response.body());
           if (!key.has("key")) {
             throw new JsonSyntaxException("Missing Dump-Url-response");
           }
           String url = "https://dump.velocitypowered.com/"
-                  + key.get("key").getAsString() + ".json";
+              + key.get("key").getAsString() + ".json";
           source.sendMessage(Component.text()
-                  .content("Created an anonymised report containing useful information about "
-                          + "this proxy. If a developer requested it, you may share the "
-                          + "following link with them:")
-                  .append(Component.newline())
-                  .append(Component.text(">> " + url)
-                          .color(NamedTextColor.GREEN)
-                          .clickEvent(ClickEvent.openUrl(url)))
-                 .append(Component.newline())
-                 .append(Component.text("Note: This link is only valid for a few days")
-                          .color(NamedTextColor.GRAY)
-                 ).build());
-        } catch (InterruptedException e) {
-          source.sendMessage(Component.text()
-                  .content("Could not complete the request, the command was interrupted."
-                          + "Please refer to the proxy-log or console for more information.")
-                  .color(NamedTextColor.RED).build());
-          logger.error("Failed to complete dump command, "
-                  + "the executor was interrupted: " + e.getMessage());
-          e.printStackTrace();
-        } catch (ExecutionException e) {
-          TextComponent.Builder message = Component.text()
-                  .content("An error occurred while attempting to upload the gathered "
-                          + "information to the Velocity servers.")
-                  .append(Component.newline())
-                  .color(NamedTextColor.RED);
-          if (e.getCause() instanceof UnknownHostException
-              || e.getCause() instanceof ConnectException) {
-            message.append(Component.text(
-                    "Likely cause: Invalid system DNS settings or no internet connection"));
-          }
-          source.sendMessage(message
-                  .append(Component.newline()
-                  .append(Component.text(
-                          "Error details can be found in the proxy log / console"))
-                  ).build());
-
-          logger.error("Failed to complete dump command, "
-                  + "the executor encountered an Exception: " + e.getCause().getMessage());
-          e.getCause().printStackTrace();
+              .content("Created an anonymised report containing useful information about "
+                  + "this proxy. If a developer requested it, you may share the "
+                  + "following link with them:")
+              .append(Component.newline())
+              .append(Component.text(">> " + url)
+                  .color(NamedTextColor.GREEN)
+                  .clickEvent(ClickEvent.openUrl(url)))
+              .append(Component.newline())
+              .append(Component.text("Note: This link is only valid for a few days")
+                  .color(NamedTextColor.GRAY)
+              ).build());
         } catch (JsonParseException e) {
           source.sendMessage(Component.text()
-                  .content("An error occurred on the Velocity servers and the dump could not "
-                          + "be completed. Please contact the Velocity staff about this problem. "
-                          + "If you do, provide the details about this error from the Velocity "
-                          + "console or server log.")
-                  .color(NamedTextColor.RED).build());
+              .content("An error occurred on the Velocity servers and the dump could not "
+                  + "be completed. Please contact the Velocity staff about this problem. "
+                  + "If you do, provide the details about this error from the Velocity "
+                  + "console or server log.")
+              .color(NamedTextColor.RED).build());
           logger.error("Invalid response from the Velocity servers: " + e.getMessage());
           e.printStackTrace();
         }
-      }, MoreExecutors.directExecutor());
+      }).exceptionally(err -> {
+        source.sendMessage(Component.text()
+            .content("An error occurred whilst gathering the dump. More information is available "
+                + "in the server console.")
+            .color(NamedTextColor.RED).build());
+        logger.error("Unable to post dump to the Velocity servers", err);
+        return null;
+      });
     }
 
     @Override

proxy/src/main/java/com/velocitypowered/proxy/connection/client/LoginSessionHandler.java

@@ -50,8 +50,14 @@ import com.velocitypowered.proxy.protocol.packet.LoginPluginResponse;
 import com.velocitypowered.proxy.protocol.packet.ServerLogin;
 import com.velocitypowered.proxy.protocol.packet.ServerLoginSuccess;
 import com.velocitypowered.proxy.protocol.packet.SetCompression;
+import com.velocitypowered.proxy.util.InformationUtils;
 import io.netty.buffer.ByteBuf;
 import java.net.InetSocketAddress;
+import java.net.URI;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.nio.charset.StandardCharsets;
 import java.security.GeneralSecurityException;
 import java.security.KeyPair;
 import java.security.MessageDigest;
@@ -132,9 +138,15 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
         url += "&ip=" + urlFormParameterEscaper().escape(playerIp);
       }
 
-      ListenableFuture<Response> hasJoinedResponse = server.getAsyncHttpClient().prepareGet(url)
-          .execute();
-      hasJoinedResponse.addListener(() -> {
+      server.getAsyncHttpClient().sendAsync(
+          HttpRequest.newBuilder()
+              .uri(URI.create(url))
+              .header("User-Agent", server.getVersion().getName() + "/"
+                  + server.getVersion().getVersion())
+              .GET()
+              .build(),
+          BodyHandlers.ofString()
+      ).thenAcceptAsync(hasJoinedResponse -> {
         if (mcConnection.isClosed()) {
           // The player disconnected after we authenticated them.
           return;
@@ -152,31 +164,30 @@ public class LoginSessionHandler implements MinecraftSessionHandler {
           return;
         }
 
-        try {
-          Response profileResponse = hasJoinedResponse.get();
-          if (profileResponse.getStatusCode() == 200) {
-            // All went well, initialize the session.
-            initializePlayer(GENERAL_GSON.fromJson(profileResponse.getResponseBody(),
-                GameProfile.class), true);
-          } else if (profileResponse.getStatusCode() == 204) {
-            // Apparently an offline-mode user logged onto this online-mode proxy.
-            inbound.disconnect(Component.translatable("velocity.error.online-mode-only",
-                NamedTextColor.RED));
-          } else {
-            // Something else went wrong
-            logger.error(
-                "Got an unexpected error code {} whilst contacting Mojang to log in {} ({})",
-                profileResponse.getStatusCode(), login.getUsername(), playerIp);
-            inbound.disconnect(Component.translatable("multiplayer.disconnect.authservers_down"));
-          }
-        } catch (ExecutionException e) {
-          logger.error("Unable to authenticate with Mojang", e);
+        if (hasJoinedResponse.statusCode() == 200) {
+          // All went well, initialize the session.
+          initializePlayer(GENERAL_GSON.fromJson(hasJoinedResponse.body(), GameProfile.class),
+              true);
+        } else if (hasJoinedResponse.statusCode() == 204) {
+          // Apparently an offline-mode user logged onto this online-mode proxy.
+          inbound.disconnect(Component.translatable("velocity.error.online-mode-only",
+              NamedTextColor.RED));
+        } else {
+          // Something else went wrong
+          logger.error(
+              "Got an unexpected error code {} whilst contacting Mojang to log in {} ({})",
+              hasJoinedResponse.statusCode(), login.getUsername(), playerIp);
           inbound.disconnect(Component.translatable("multiplayer.disconnect.authservers_down"));
-        } catch (InterruptedException e) {
-          // not much we can do usefully
-          Thread.currentThread().interrupt();
         }
-      }, mcConnection.eventLoop());
+      }, mcConnection.eventLoop()).exceptionally(err -> {
+        mcConnection.eventLoop().execute(() -> {
+          if (!mcConnection.isClosed()) {
+            logger.error("Unable to enable encryption", err);
+            mcConnection.close(true);
+          }
+        });
+        return null;
+      });
     } catch (GeneralSecurityException e) {
       logger.error("Unable to enable encryption", e);
       mcConnection.close(true);

proxy/src/main/java/com/velocitypowered/proxy/network/ConnectionManager.java

@@ -17,9 +17,6 @@
 
 package com.velocitypowered.proxy.network;
 
-import static org.asynchttpclient.Dsl.asyncHttpClient;
-import static org.asynchttpclient.Dsl.config;
-
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.event.proxy.ListenerBoundEvent;
 import com.velocitypowered.api.event.proxy.ListenerCloseEvent;
@@ -38,15 +35,11 @@ import io.netty.channel.WriteBufferWaterMark;
 import io.netty.channel.epoll.EpollChannelOption;
 import io.netty.util.concurrent.GlobalEventExecutor;
 import java.net.InetSocketAddress;
+import java.net.http.HttpClient;
 import java.util.HashMap;
 import java.util.Map;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.asynchttpclient.AsyncHttpClient;
-import org.asynchttpclient.RequestBuilder;
-import org.asynchttpclient.filter.FilterContext;
-import org.asynchttpclient.filter.FilterContext.FilterContextBuilder;
-import org.asynchttpclient.filter.RequestFilter;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public final class ConnectionManager {
@@ -67,7 +60,7 @@ public final class ConnectionManager {
   public final BackendChannelInitializerHolder backendChannelInitializer;
 
   private final SeparatePoolInetNameResolver resolver;
-  private final AsyncHttpClient httpClient;
+  private final HttpClient httpClient;
 
   /**
    * Initalizes the {@code ConnectionManager}.
@@ -84,20 +77,7 @@ public final class ConnectionManager {
     this.backendChannelInitializer = new BackendChannelInitializerHolder(
         new BackendChannelInitializer(this.server));
     this.resolver = new SeparatePoolInetNameResolver(GlobalEventExecutor.INSTANCE);
-    this.httpClient = asyncHttpClient(config()
-        .setEventLoopGroup(this.workerGroup)
-        .setUserAgent(server.getVersion().getName() + "/" + server.getVersion().getVersion())
-        .addRequestFilter(new RequestFilter() {
-          @Override
-          public <T> FilterContext<T> filter(FilterContext<T> ctx) {
-            return new FilterContextBuilder<>(ctx)
-                .request(new RequestBuilder(ctx.getRequest())
-                    .setNameResolver(resolver)
-                    .build())
-                .build();
-          }
-        })
-        .build());
+    this.httpClient = HttpClient.newBuilder().build();
   }
 
   public void logChannelInformation() {
@@ -241,7 +221,7 @@ public final class ConnectionManager {
     return this.serverChannelInitializer;
   }
 
-  public AsyncHttpClient getHttpClient() {
+  public HttpClient getHttpClient() {
     return httpClient;
   }