Added checking for Mojang blocked servers

README.md

@@ -12,7 +12,7 @@ Hi there! Looking for usage? View the [Wiki](https://git.rainnny.club/Rainnny/RE
 ## TODO
 - [x] Server Icon Route
 - [ ] Unit Tests
-- [ ] Blacklist Checking
+- [x] Blacklist Checking
 - [x] HTTP Codes in wiki
 - [ ] Route for 3D player heads/body?
 

pom.xml

@@ -89,6 +89,12 @@
             <version>2.10.1</version>
             <scope>compile</scope>
         </dependency>
+        <dependency>
+            <groupId>net.jodah</groupId>
+            <artifactId>expiringmap</artifactId>
+            <version>0.5.11</version>
+            <scope>compile</scope>
+        </dependency>
 
         <!-- DNS Lookup -->
         <dependency>

src/main/java/me/braydon/mc/common/ExpiringSet.java

@@ -0,0 +1,134 @@
+package me.braydon.mc.common;
+
+import lombok.NonNull;
+import net.jodah.expiringmap.ExpirationPolicy;
+import net.jodah.expiringmap.ExpiringMap;
+
+import javax.annotation.concurrent.ThreadSafe;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
+
+/**
+ * A simple set that expires elements after a certain
+ * amount of time, utilizing the {@link ExpiringMap} library.
+ *
+ * @param <T> The type of element to store within this set
+ * @author Braydon
+ */
+@ThreadSafe
+public final class ExpiringSet<T> implements Iterable<T> {
+    /**
+     * The internal cache for this set.
+     */
+    @NonNull private final ExpiringMap<T, Long> cache;
+
+    /**
+     * The lifetime (in millis) of the elements in this set.
+     */
+    private final long lifetime;
+
+    public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit) {
+        this(expirationPolicy, duration, timeUnit, ignored -> {});
+    }
+
+    public ExpiringSet(@NonNull ExpirationPolicy expirationPolicy, long duration, @NonNull TimeUnit timeUnit, @NonNull Consumer<T> onExpire) {
+        //noinspection unchecked
+        this.cache = ExpiringMap.builder()
+                .expirationPolicy(expirationPolicy)
+                .expiration(duration, timeUnit)
+                .expirationListener((key, ignored) -> onExpire.accept((T) key))
+                .build();
+        this.lifetime = timeUnit.toMillis(duration); // Get the lifetime in millis
+    }
+
+    /**
+     * Add an element to this set.
+     *
+     * @param element the element
+     * @return whether the element was added
+     */
+    public boolean add(@NonNull T element) {
+        boolean contains = contains(element); // Does this set already contain the element?
+        this.cache.put(element, System.currentTimeMillis() + this.lifetime);
+        return !contains;
+    }
+
+    /**
+     * Get the entry time of an element in this set.
+     *
+     * @param element the element
+     * @return the entry time, -1 if not contained
+     */
+    public long getEntryTime(@NonNull T element) {
+        return contains(element) ? this.cache.get(element) - this.lifetime : -1L;
+    }
+
+    /**
+     * Check if an element is
+     * contained within this set.
+     *
+     * @param element the element
+     * @return whether the element is contained
+     */
+    public boolean contains(@NonNull T element) {
+        Long timeout = this.cache.get(element); // Get the timeout for the element
+        return timeout != null && (timeout > System.currentTimeMillis());
+    }
+
+    /**
+     * Check if this set is empty.
+     *
+     * @return whether this set is empty
+     */
+    public boolean isEmpty() {
+        return this.cache.isEmpty();
+    }
+
+    /**
+     * Get the size of this set.
+     *
+     * @return the size
+     */
+    public int size() {
+        return this.cache.size();
+    }
+
+    /**
+     * Remove an element from this set.
+     *
+     * @param element the element
+     * @return whether the element was removed
+     */
+    public boolean remove(@NonNull T element) {
+        return this.cache.remove(element) != null;
+    }
+
+    /**
+     * Clear this set.
+     */
+    public void clear() {
+        this.cache.clear();
+    }
+
+    /**
+     * Get the elements in this set.
+     *
+     * @return the elements
+     */
+    @NonNull
+    public Set<T> getElements() {
+        return this.cache.keySet();
+    }
+
+    /**
+     * Returns an iterator over elements of type {@code T}.
+     *
+     * @return an Iterator.
+     */
+    @Override @NonNull
+    public Iterator<T> iterator() {
+        return this.cache.keySet().iterator();
+    }
+}

src/main/java/me/braydon/mc/controller/ServerController.java

@@ -689,6 +689,8 @@ import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import java.util.Map;
+
 /**
  * The controller for handling
  * {@link MinecraftServer} related requests.
@@ -721,12 +723,27 @@ public final class ServerController {
      */
     @GetMapping("/{platform}/{hostname}")
     @ResponseBody
-    public ResponseEntity<CachedMinecraftServer> getServer(@PathVariable @NonNull String platform,@PathVariable @NonNull String hostname)
+    public ResponseEntity<CachedMinecraftServer> getServer(@PathVariable @NonNull String platform, @PathVariable @NonNull String hostname)
             throws BadRequestException, InvalidMinecraftServerPlatform, ResourceNotFoundException
     {
         return ResponseEntity.ofNullable(mojangService.getMinecraftServer(platform, hostname));
     }
 
+    /**
+     * Check if the server with the
+     * given hostname is blocked by Mojang.
+     *
+     * @param hostname the server hostname to check
+     * @return whether the hostname is blocked
+     */
+    @GetMapping("/blocked/{hostname}")
+    @ResponseBody
+    public ResponseEntity<Map<String, Object>> isServerBlocked(@PathVariable @NonNull String hostname) {
+        return ResponseEntity.ok(Map.of(
+                "blocked", mojangService.isServerBlocked(hostname)
+        ));
+    }
+
     /**
      * Get the server icon of a Minecraft
      * server by its platform and hostname.

src/main/java/me/braydon/mc/model/server/JavaMinecraftServer.java

@@ -677,14 +677,12 @@
 package me.braydon.mc.model.server;
 
 import com.google.gson.annotations.SerializedName;
-import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.NonNull;
-import lombok.ToString;
+import lombok.*;
 import me.braydon.mc.RESTfulMC;
 import me.braydon.mc.common.MinecraftVersion;
 import me.braydon.mc.model.MinecraftServer;
 import me.braydon.mc.model.token.JavaServerStatusToken;
+import me.braydon.mc.service.MojangService;
 import net.md_5.bungee.api.chat.TextComponent;
 import net.md_5.bungee.chat.ComponentSerializer;
 
@@ -693,7 +691,7 @@ import net.md_5.bungee.chat.ComponentSerializer;
  *
  * @author Braydon
  */
-@Getter
+@Setter @Getter
 public final class JavaMinecraftServer extends MinecraftServer {
     /**
      * The version information of this server.
@@ -718,10 +716,15 @@ public final class JavaMinecraftServer extends MinecraftServer {
     /**
      * Is this server on the list
      * of blocked servers by Mojang?
+     * <p>
+     * This value is later set by the
+     * {@link MojangService} when a server
+     * is requested.
+     * </p>
      *
      * @see <a href="https://wiki.vg/Mojang_API#Blocked_Servers">Mojang API</a>
      */
-    private final boolean mojangBanned;
+    private boolean mojangBanned;
 
     private JavaMinecraftServer(@NonNull String hostname, String ip, int port, @NonNull Players players,
                                 Favicon favicon, @NonNull MOTD motd, @NonNull Version version, ModInfo modInfo,

src/main/java/me/braydon/mc/service/MojangService.java

@@ -676,7 +676,13 @@
  */
 package me.braydon.mc.service;
 
+import com.google.common.base.Joiner;
+import com.google.common.base.Splitter;
+import com.google.common.collect.Lists;
+import com.google.common.hash.Hashing;
+import jakarta.annotation.PostConstruct;
 import lombok.NonNull;
+import lombok.SneakyThrows;
 import lombok.extern.log4j.Log4j2;
 import me.braydon.mc.common.*;
 import me.braydon.mc.common.web.JsonWebException;
@@ -688,19 +694,23 @@ import me.braydon.mc.model.*;
 import me.braydon.mc.model.cache.CachedMinecraftServer;
 import me.braydon.mc.model.cache.CachedPlayer;
 import me.braydon.mc.model.cache.CachedPlayerName;
+import me.braydon.mc.model.server.JavaMinecraftServer;
 import me.braydon.mc.model.token.MojangProfileToken;
 import me.braydon.mc.model.token.MojangUsernameToUUIDToken;
 import me.braydon.mc.repository.MinecraftServerCacheRepository;
 import me.braydon.mc.repository.PlayerCacheRepository;
 import me.braydon.mc.repository.PlayerNameCacheRepository;
+import net.jodah.expiringmap.ExpirationPolicy;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpMethod;
 import org.springframework.stereotype.Service;
 
+import java.io.InputStream;
 import java.net.InetSocketAddress;
-import java.util.Base64;
-import java.util.Optional;
-import java.util.UUID;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.*;
+import java.util.concurrent.TimeUnit;
 
 /**
  * A service for interacting with the Mojang API.
@@ -714,12 +724,16 @@ public final class MojangService {
     private static final String API_ENDPOINT = "https://api.mojang.com";
     private static final String UUID_TO_PROFILE = SESSION_SERVER_ENDPOINT + "/session/minecraft/profile/%s";
     private static final String USERNAME_TO_UUID = API_ENDPOINT + "/users/profiles/minecraft/%s";
+    private static final String FETCH_BLOCKED_SERVERS = SESSION_SERVER_ENDPOINT + "/blockedservers";
 
     private static final int DEFAULT_PART_TEXTURE_SIZE = 128;
     private static final int MAX_PART_TEXTURE_SIZE = 512;
 
     private static final String DEFAULT_SERVER_ICON = "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";
 
+    private static final Splitter DOT_SPLITTER = Splitter.on('.');
+    private static final Joiner DOT_JOINER = Joiner.on('.');
+
     /**
      * The cache repository for {@link Player}'s by their username.
      */
@@ -735,6 +749,24 @@ public final class MojangService {
      */
     @NonNull private final MinecraftServerCacheRepository minecraftServerCache;
 
+    /**
+     * A list of banned server hashes provided by Mojang.
+     * <p>
+     * This is periodically fetched from Mojang, see
+     * {@link #fetchBlockedServers()} for more info.
+     * </p>
+     *
+     * @see <a href="https://wiki.vg/Mojang_API#Blocked_Servers">Mojang API</a>
+     */
+    private List<String> bannedServerHashes;
+
+    /**
+     * A cache of blocked server hostnames.
+     *
+     * @see #isServerHostnameBlocked(String) for more
+     */
+    private final ExpiringSet<String> blockedServersCache = new ExpiringSet<>(ExpirationPolicy.CREATED, 10L, TimeUnit.MINUTES);
+
     @Autowired
     public MojangService(@NonNull PlayerNameCacheRepository playerNameCache, @NonNull PlayerCacheRepository playerCache,
                          @NonNull MinecraftServerCacheRepository minecraftServerCache) {
@@ -743,6 +775,18 @@ public final class MojangService {
         this.minecraftServerCache = minecraftServerCache;
     }
 
+    @PostConstruct
+    public void onInitialize() {
+        // Schedule a task to fetch blocked
+        // servers from Mojang every 15 minutes.
+        new Timer().scheduleAtFixedRate(new TimerTask() {
+            @Override
+            public void run() {
+                fetchBlockedServers();
+            }
+        }, 0L, 60L * 15L * 1000L);
+    }
+
     /**
      * Get the part of a skin texture for
      * a player by their username or UUID.
@@ -886,16 +930,63 @@ public final class MojangService {
         return Base64.getDecoder().decode(icon); // Return the decoded favicon
     }
 
+    /**
+     * Check if the server with the
+     * given hostname is blocked by Mojang.
+     *
+     * @param hostname the server hostname to check
+     * @return whether the hostname is blocked
+     */
+    public boolean isServerBlocked(@NonNull String hostname) {
+        // Remove trailing dots
+        while (hostname.charAt(hostname.length() - 1) == '.') {
+            hostname = hostname.substring(0, hostname.length() - 1);
+        }
+        // Is the hostname banned?
+        if (isServerHostnameBlocked(hostname)) {
+            return true;
+        }
+        List<String> splitDots = Lists.newArrayList(DOT_SPLITTER.split(hostname)); // Split the hostname by dots
+        boolean isIp = splitDots.size() == 4; // Is it an IP address?
+        if (isIp) {
+            for (String element : splitDots) {
+                try {
+                    int part = Integer.parseInt(element);
+                    if (part >= 0 && part <= 255) { // Ensure the part is within the valid range
+                        continue;
+                    }
+                } catch (NumberFormatException ignored) {
+                    // Safely ignore, not a number
+                }
+                isIp = false;
+                break;
+            }
+        }
+        // Check if the hostname is blocked
+        if (!isIp && isServerHostnameBlocked("*." + hostname)) {
+            return true;
+        }
+        // Additional checks for the hostname
+        while (splitDots.size() > 1) {
+            splitDots.remove(isIp ? splitDots.size() - 1 : 0);
+            String starredPart = isIp ? DOT_JOINER.join(splitDots) + ".*" : "*." + DOT_JOINER.join(splitDots);
+            if (isServerHostnameBlocked(starredPart)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Resolve a Minecraft server on the given
      * platform with the given hostname.
      *
      * @param platformName the name of the platform
-     * @param hostname the hostname of the server
+     * @param hostname     the hostname of the server
      * @return the resolved Minecraft server
-     * @throws BadRequestException if the hostname is unknown
+     * @throws BadRequestException            if the hostname is unknown
      * @throws InvalidMinecraftServerPlatform if the platform is invalid
-     * @throws ResourceNotFoundException if the server isn't found
+     * @throws ResourceNotFoundException      if the server isn't found
      */
     @NonNull
     public CachedMinecraftServer getMinecraftServer(@NonNull String platformName, @NonNull String hostname)
@@ -925,6 +1016,12 @@ public final class MojangService {
                 platform.getPinger().ping(hostname, port),
                 System.currentTimeMillis()
         );
+
+        // Get the blocked status of the Java server
+        if (platform == MinecraftServer.Platform.JAVA) {
+            ((JavaMinecraftServer) minecraftServer.getValue()).setMojangBanned(isServerBlocked(hostname));
+        }
+
         minecraftServerCache.save(minecraftServer);
         log.info("Cached server: {}", hostname);
         minecraftServer.setCached(-1L); // Set to -1 to indicate it's not cached in the response
@@ -967,4 +1064,42 @@ public final class MojangService {
             throw ex;
         }
     }
+
+    /**
+     * Fetch a list of blocked servers from Mojang.
+     */
+    @SneakyThrows
+    private void fetchBlockedServers() {
+        try (
+                InputStream inputStream = new URL(FETCH_BLOCKED_SERVERS).openStream();
+                Scanner scanner = new Scanner(inputStream, StandardCharsets.UTF_8).useDelimiter("\n");
+        ) {
+            List<String> hashes = new ArrayList<>();
+            while (scanner.hasNext()) {
+                hashes.add(scanner.next());
+            }
+            bannedServerHashes = Collections.synchronizedList(hashes);
+            log.info("Fetched {} banned server hashes", bannedServerHashes.size());
+        }
+    }
+
+    /**
+     * Check if the hash for the given
+     * hostname is in the blocked server list.
+     *
+     * @param hostname the hostname to check
+     * @return whether the hostname is blocked
+     */
+    private boolean isServerHostnameBlocked(@NonNull String hostname) {
+        // Check the cache first for the hostname
+        if (blockedServersCache.contains(hostname)) {
+            return true;
+        }
+        String hashed = Hashing.sha1().hashBytes(hostname.toLowerCase().getBytes(StandardCharsets.ISO_8859_1)).toString();
+        boolean blocked = bannedServerHashes.contains(hashed); // Is the hostname blocked?
+        if (blocked) { // Cache the blocked hostname
+            blockedServersCache.add(hostname);
+        }
+        return blocked;
+    }
 }