Initial placeholders support for backend servers

build.gradle

@@ -185,7 +185,7 @@ publishing {
 javadoc {
     getOptions().setEncoding("UTF-8")
     getOptions().setCharSet("UTF-8")
-    getOptions().setSource("11")
+    getOptions().setSource("17")
     getOptions().links("https://docs.oracle.com/en/java/javase/11/docs/api/")
 
     // Remove "undefined" from search paths when generating javadoc for a non-modular project. (JDK-8215291)

src/main/java/net/elytrium/limboauth/LimboAuth.java

@@ -108,6 +108,7 @@
 import net.elytrium.limboauth.floodgate.FloodgateApiHolder;
 import net.elytrium.limboauth.handler.AuthSessionHandler;
 import net.elytrium.limboauth.listener.AuthListener;
+import net.elytrium.limboauth.listener.BackendEndpointsListener;
 import net.elytrium.limboauth.model.RegisteredPlayer;
 import net.elytrium.limboauth.model.SQLRuntimeException;
 import net.kyori.adventure.text.Component;
@@ -405,6 +406,11 @@ public void reload() {
     EventManager eventManager = this.server.getEventManager();
     eventManager.unregisterListeners(this);
     eventManager.register(this, new AuthListener(this, this.playerDao, this.floodgateApi));
+    if (Settings.IMP.MAIN.BACKEND_API.ENABLED) {
+      eventManager.register(this, new BackendEndpointsListener(this));
+    } else {
+      this.server.getChannelRegistrar().unregister(BackendEndpointsListener.API_CHANNEL);
+    }
 
     if (this.purgeCacheTask != null) {
       this.purgeCacheTask.cancel();

src/main/java/net/elytrium/limboauth/Settings.java

@@ -306,6 +306,27 @@ public Title.Times toTimes() {
       }
     }
 
+    @Create
+    public Settings.MAIN.BACKEND_API BACKEND_API;
+
+    public static class BACKEND_API {
+
+      @Comment({
+          "Should backend API be enabled?",
+          "Required for PlaceholderAPI expansion to work (https://github.com/UserNugget/LimboAuth-Expansion)"
+      })
+      public boolean ENABLED = true;
+
+      @Comment({
+          "Available endpoints:",
+          " premium_state, hash, totp_token, login_date, reg_date, token_issued_at,",
+          " uuid, premium_uuid, ip, login_ip, token_issued_at"
+      })
+      public List<String> ENABLED_ENDPOINTS = List.of(
+          "premium_state", "login_date", "reg_date", "uuid", "premium_uuid", "token_issued_at"
+      );
+    }
+
     @Create
     public MAIN.COMMAND_PERMISSION_STATE COMMAND_PERMISSION_STATE;
 

src/main/java/net/elytrium/limboauth/backend/Endpoint.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import net.elytrium.limboauth.LimboAuth;
+
+public abstract class Endpoint {
+
+  protected final LimboAuth plugin;
+
+  public Endpoint(LimboAuth plugin) {
+    this.plugin = plugin;
+  }
+
+  public abstract void write(ByteArrayDataOutput output);
+
+  public abstract void read(ByteArrayDataInput input);
+}

src/main/java/net/elytrium/limboauth/backend/type/LongDatabaseEndpoint.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend.type;
+
+import java.util.function.Function;
+import net.elytrium.limboauth.LimboAuth;
+import net.elytrium.limboauth.handler.AuthSessionHandler;
+import net.elytrium.limboauth.model.RegisteredPlayer;
+
+public class LongDatabaseEndpoint extends LongEndpoint {
+
+  public LongDatabaseEndpoint(LimboAuth plugin, String type, String username, long value) {
+    super(plugin, type, username, value);
+  }
+
+  public LongDatabaseEndpoint(LimboAuth plugin, String type, Function<RegisteredPlayer, Long> function) {
+    super(plugin, type, username -> {
+      RegisteredPlayer player = AuthSessionHandler.fetchInfo(plugin.getPlayerDao(), username);
+      if (player == null) {
+        return Long.MIN_VALUE;
+      } else {
+        return function.apply(player);
+      }
+    });
+  }
+}

src/main/java/net/elytrium/limboauth/backend/type/LongEndpoint.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend.type;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import java.util.function.Function;
+import net.elytrium.limboauth.LimboAuth;
+import net.elytrium.limboauth.Settings;
+import net.elytrium.limboauth.backend.Endpoint;
+
+public class LongEndpoint extends Endpoint {
+
+  private String type;
+  private Function<String, Long> function;
+  private String username;
+  private long value;
+
+  public LongEndpoint(LimboAuth plugin, String type, Function<String, Long> function) {
+    super(plugin);
+    this.type = type;
+    this.function = function;
+  }
+
+  public LongEndpoint(LimboAuth plugin, String type, String username, long value) {
+    super(plugin);
+    this.type = type;
+    this.username = username;
+    this.value = value;
+  }
+
+  @Override
+  public void write(ByteArrayDataOutput output) {
+    output.writeUTF(this.type);
+    if (!Settings.IMP.MAIN.BACKEND_API.ENABLED_ENDPOINTS.contains(this.type)) {
+      output.writeInt(-1);
+      output.writeUTF(this.username);
+      return;
+    }
+
+    output.writeInt(0);
+    output.writeUTF(this.username);
+    output.writeLong(this.value);
+  }
+
+  @Override
+  public void read(ByteArrayDataInput input) {
+    int version = input.readInt();
+    if (version != 0) {
+      throw new IllegalStateException("unsupported '" + this.type + "' endpoint version: " + version);
+    }
+
+    this.username = input.readUTF();
+    this.value = this.function.apply(this.username);
+  }
+
+  @Override
+  public String toString() {
+    return "LongEndpoint{"
+        + "username='" + this.username + '\''
+        + ", value=" + this.value
+        + '}';
+  }
+}

src/main/java/net/elytrium/limboauth/backend/type/StringDatabaseEndpoint.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend.type;
+
+import java.util.function.Function;
+import net.elytrium.limboauth.LimboAuth;
+import net.elytrium.limboauth.handler.AuthSessionHandler;
+import net.elytrium.limboauth.model.RegisteredPlayer;
+
+public class StringDatabaseEndpoint extends StringEndpoint {
+
+  public StringDatabaseEndpoint(LimboAuth plugin, String type, String username, String value) {
+    super(plugin, type, username, value);
+  }
+
+  public StringDatabaseEndpoint(LimboAuth plugin, String type, Function<RegisteredPlayer, String> function) {
+    super(plugin, type, username -> {
+      RegisteredPlayer player = AuthSessionHandler.fetchInfo(plugin.getPlayerDao(), username);
+      if (player == null) {
+        return "";
+      } else {
+        return function.apply(player);
+      }
+    });
+  }
+}

src/main/java/net/elytrium/limboauth/backend/type/StringEndpoint.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend.type;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import java.util.function.Function;
+import net.elytrium.limboauth.LimboAuth;
+import net.elytrium.limboauth.Settings;
+import net.elytrium.limboauth.backend.Endpoint;
+
+public class StringEndpoint extends Endpoint {
+
+  private String type;
+  private Function<String, String> function;
+  private String username;
+  private String value;
+
+  public StringEndpoint(LimboAuth plugin, String type, Function<String, String> function) {
+    super(plugin);
+    this.type = type;
+    this.function = function;
+  }
+
+  public StringEndpoint(LimboAuth plugin, String type, String username, String value) {
+    super(plugin);
+    this.type = type;
+    this.username = username;
+    this.value = value;
+  }
+
+  @Override
+  public void write(ByteArrayDataOutput output) {
+    output.writeUTF(this.type);
+    if (!this.type.equals("available_endpoints") && !Settings.IMP.MAIN.BACKEND_API.ENABLED_ENDPOINTS.contains(this.type)) {
+      output.writeInt(-1);
+      output.writeUTF(this.username);
+      return;
+    }
+
+    output.writeInt(0);
+    output.writeUTF(this.username);
+    output.writeUTF(this.value);
+  }
+
+  @Override
+  public void read(ByteArrayDataInput input) {
+    int version = input.readInt();
+    if (version != 0) {
+      throw new IllegalStateException("unsupported '" + this.type + "' endpoint version: " + version);
+    }
+
+    this.username = input.readUTF();
+    this.value = this.function.apply(this.username);
+  }
+
+  @Override
+  public String toString() {
+    return "StringEndpoint{"
+        + "username='" + this.username + '\''
+        + ", value=" + this.value
+        + '}';
+  }
+}

src/main/java/net/elytrium/limboauth/backend/type/UnknownEndpoint.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2021 - 2024 Elytrium
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.elytrium.limboauth.backend.type;
+
+import com.google.common.io.ByteArrayDataInput;
+import com.google.common.io.ByteArrayDataOutput;
+import net.elytrium.limboauth.LimboAuth;
+import net.elytrium.limboauth.backend.Endpoint;
+
+public class UnknownEndpoint extends Endpoint {
+
+  private String type;
+
+  public UnknownEndpoint(LimboAuth plugin) {
+    super(plugin);
+  }
+
+  public UnknownEndpoint(LimboAuth plugin, String type) {
+    super(plugin);
+    this.type = type;
+  }
+
+  @Override
+  public void write(ByteArrayDataOutput output) {
+    output.writeUTF(this.type);
+    output.writeInt(-2);
+  }
+
+  @Override
+  public void read(ByteArrayDataInput input) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public String toString() {
+    return "UnknownEndpoint{"
+        + "type='" + this.type + '\''
+        + '}';
+  }
+}