Added message types to fetch account details and account balances, and use these in various APIs.

This should bring in enough data for very basic chat and wallet functionality (using addresses rather than registered names).

Data currently comes from a single random peer, however this can be expanded to request from multiple peers to gain confidence in the accuracy of the data. If bad data is returned from a peer, it's not the end of the world since the transaction would just be considered invalid by full nodes and would be thrown out. But this should be mostly avoidable by taking data from multiple sources to improve confidence in its accuracy.

src/main/java/org/qortal/account/Account.java

@@ -8,11 +8,13 @@ import javax.xml.bind.annotation.XmlAccessorType;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.qortal.block.BlockChain;
+import org.qortal.controller.LiteNode;
 import org.qortal.data.account.AccountBalanceData;
 import org.qortal.data.account.AccountData;
 import org.qortal.data.account.RewardShareData;
 import org.qortal.repository.DataException;
 import org.qortal.repository.Repository;
+import org.qortal.settings.Settings;
 import org.qortal.utils.Base58;
 
 @XmlAccessorType(XmlAccessType.NONE) // Stops JAX-RS errors when unmarshalling blockchain config
@@ -59,7 +61,17 @@ public class Account {
 	// Balance manipulations - assetId is 0 for QORT
 
 	public long getConfirmedBalance(long assetId) throws DataException {
-		AccountBalanceData accountBalanceData = this.repository.getAccountRepository().getBalance(this.address, assetId);
+		AccountBalanceData accountBalanceData;
+
+		if (Settings.getInstance().isLite()) {
+			// Lite nodes request data from peers instead of the local db
+			accountBalanceData = LiteNode.getInstance().fetchAccountBalance(this.address, assetId);
+		}
+		else {
+			// All other node types fetch from the local db
+			accountBalanceData = this.repository.getAccountRepository().getBalance(this.address, assetId);
+		}
+
 		if (accountBalanceData == null)
 			return 0;
 

src/main/java/org/qortal/api/resource/AddressesResource.java

@@ -30,6 +30,7 @@ import org.qortal.api.Security;
 import org.qortal.api.model.ApiOnlineAccount;
 import org.qortal.api.model.RewardShareKeyRequest;
 import org.qortal.asset.Asset;
+import org.qortal.controller.LiteNode;
 import org.qortal.controller.OnlineAccountsManager;
 import org.qortal.crypto.Crypto;
 import org.qortal.data.account.AccountData;
@@ -109,18 +110,26 @@ public class AddressesResource {
 		if (!Crypto.isValidAddress(address))
 			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.INVALID_ADDRESS);
 
-		byte[] lastReference = null;
+		AccountData accountData;
 
-		try (final Repository repository = RepositoryManager.getRepository()) {
-			AccountData accountData = repository.getAccountRepository().getAccount(address);
-			// Not found?
-			if (accountData == null)
-				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
-
-			lastReference = accountData.getReference();
-		} catch (DataException e) {
-			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+		if (Settings.getInstance().isLite()) {
+			// Lite nodes request data from peers instead of the local db
+			accountData = LiteNode.getInstance().fetchAccountData(address);
 		}
+		else {
+			// All other node types request data from local db
+			try (final Repository repository = RepositoryManager.getRepository()) {
+				accountData = repository.getAccountRepository().getAccount(address);
+			} catch (DataException e) {
+				throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.REPOSITORY_ISSUE, e);
+			}
+		}
+
+		// Not found?
+		if (accountData == null)
+			throw ApiExceptionFactory.INSTANCE.createException(request, ApiError.ADDRESS_UNKNOWN);
+
+		byte[] lastReference = accountData.getReference();
 
 		if (lastReference == null || lastReference.length == 0)
 			return "false";

src/main/java/org/qortal/controller/Controller.java

@@ -39,6 +39,8 @@ import org.qortal.controller.arbitrary.*;
 import org.qortal.controller.repository.PruneManager;
 import org.qortal.controller.repository.NamesDatabaseIntegrityCheck;
 import org.qortal.controller.tradebot.TradeBot;
+import org.qortal.data.account.AccountBalanceData;
+import org.qortal.data.account.AccountData;
 import org.qortal.data.block.BlockData;
 import org.qortal.data.block.BlockSummaryData;
 import org.qortal.data.network.PeerChainTipData;
@@ -178,6 +180,28 @@ public class Controller extends Thread {
 		}
 		public GetArbitraryMetadataMessageStats getArbitraryMetadataMessageStats = new GetArbitraryMetadataMessageStats();
 
+		public static class GetAccountMessageStats {
+			public AtomicLong requests = new AtomicLong();
+			public AtomicLong cacheHits = new AtomicLong();
+			public AtomicLong unknownAccounts = new AtomicLong();
+			public AtomicLong cacheFills = new AtomicLong();
+
+			public GetAccountMessageStats() {
+			}
+		}
+		public GetAccountMessageStats getAccountMessageStats = new GetAccountMessageStats();
+
+		public static class GetAccountBalanceMessageStats {
+			public AtomicLong requests = new AtomicLong();
+			public AtomicLong cacheHits = new AtomicLong();
+			public AtomicLong unknownAccounts = new AtomicLong();
+			public AtomicLong cacheFills = new AtomicLong();
+
+			public GetAccountBalanceMessageStats() {
+			}
+		}
+		public GetAccountBalanceMessageStats getAccountBalanceMessageStats = new GetAccountBalanceMessageStats();
+
 		public AtomicLong latestBlocksCacheRefills = new AtomicLong();
 
 		public StatsSnapshot() {
@@ -1232,6 +1256,14 @@ public class Controller extends Thread {
 				TradeBot.getInstance().onTradePresencesMessage(peer, message);
 				break;
 
+			case GET_ACCOUNT:
+				onNetworkGetAccountMessage(peer, message);
+				break;
+
+			case GET_ACCOUNT_BALANCE:
+				onNetworkGetAccountBalanceMessage(peer, message);
+				break;
+
 			default:
 				LOGGER.debug(() -> String.format("Unhandled %s message [ID %d] from peer %s", message.getType().name(), message.getId(), peer));
 				break;
@@ -1483,6 +1515,77 @@ public class Controller extends Thread {
 		Synchronizer.getInstance().requestSync();
 	}
 
+	private void onNetworkGetAccountMessage(Peer peer, Message message) {
+		GetAccountMessage getAccountMessage = (GetAccountMessage) message;
+		String address = getAccountMessage.getAddress();
+		this.stats.getAccountMessageStats.requests.incrementAndGet();
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			AccountData accountData = repository.getAccountRepository().getAccount(address);
+
+			if (accountData == null) {
+				// We don't have this account
+				this.stats.getAccountMessageStats.unknownAccounts.getAndIncrement();
+
+				// Send valid, yet unexpected message type in response, so peer doesn't have to wait for timeout
+				LOGGER.debug(() -> String.format("Sending 'account unknown' response to peer %s for GET_ACCOUNT request for unknown account %s", peer, address));
+
+				// We'll send empty block summaries message as it's very short
+				Message accountUnknownMessage = new BlockSummariesMessage(Collections.emptyList());
+				accountUnknownMessage.setId(message.getId());
+				if (!peer.sendMessage(accountUnknownMessage))
+					peer.disconnect("failed to send account-unknown response");
+				return;
+			}
+
+			AccountMessage accountMessage = new AccountMessage(accountData);
+			accountMessage.setId(message.getId());
+
+			if (!peer.sendMessage(accountMessage)) {
+				peer.disconnect("failed to send account");
+			}
+
+		} catch (DataException e) {
+			LOGGER.error(String.format("Repository issue while send account %s to peer %s", address, peer), e);
+		}
+	}
+
+	private void onNetworkGetAccountBalanceMessage(Peer peer, Message message) {
+		GetAccountBalanceMessage getAccountBalanceMessage = (GetAccountBalanceMessage) message;
+		String address = getAccountBalanceMessage.getAddress();
+		long assetId = getAccountBalanceMessage.getAssetId();
+		this.stats.getAccountBalanceMessageStats.requests.incrementAndGet();
+
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			AccountBalanceData accountBalanceData = repository.getAccountRepository().getBalance(address, assetId);
+
+			if (accountBalanceData == null) {
+				// We don't have this account
+				this.stats.getAccountBalanceMessageStats.unknownAccounts.getAndIncrement();
+
+				// Send valid, yet unexpected message type in response, so peer doesn't have to wait for timeout
+				LOGGER.debug(() -> String.format("Sending 'account unknown' response to peer %s for GET_ACCOUNT request for unknown account %s and asset ID %d", peer, address, assetId));
+
+				// We'll send empty block summaries message as it's very short
+				Message accountUnknownMessage = new BlockSummariesMessage(Collections.emptyList());
+				accountUnknownMessage.setId(message.getId());
+				if (!peer.sendMessage(accountUnknownMessage))
+					peer.disconnect("failed to send account-unknown response");
+				return;
+			}
+
+			AccountBalanceMessage accountMessage = new AccountBalanceMessage(accountBalanceData);
+			accountMessage.setId(message.getId());
+
+			if (!peer.sendMessage(accountMessage)) {
+				peer.disconnect("failed to send account");
+			}
+
+		} catch (DataException e) {
+			LOGGER.error(String.format("Repository issue while send balance for account %s and asset ID %d to peer %s", address, assetId, peer), e);
+		}
+	}
+
 
 	// Utilities
 

src/main/java/org/qortal/controller/LiteNode.java

@@ -0,0 +1,117 @@
+package org.qortal.controller;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.qortal.data.account.AccountBalanceData;
+import org.qortal.data.account.AccountData;
+import org.qortal.network.Network;
+import org.qortal.network.Peer;
+import org.qortal.network.message.*;
+
+import java.security.SecureRandom;
+import java.util.*;
+
+import static org.qortal.network.message.Message.MessageType;
+import static org.qortal.network.message.Message.MessageType.*;
+
+public class LiteNode {
+
+    private static final Logger LOGGER = LogManager.getLogger(LiteNode.class);
+
+    private static LiteNode instance;
+
+
+    public Map<Integer, Long> pendingRequests = Collections.synchronizedMap(new HashMap<>());
+
+
+    public LiteNode() {
+
+    }
+
+    public static synchronized LiteNode getInstance() {
+        if (instance == null) {
+            instance = new LiteNode();
+        }
+
+        return instance;
+    }
+
+
+    /**
+     * Fetch account data from peers for given QORT address
+     * @param address - the QORT address to query
+     * @return accountData - the account data for this address, or null if not retrieved
+     */
+    public AccountData fetchAccountData(String address) {
+        GetAccountMessage getAccountMessage = new GetAccountMessage(address);
+        AccountMessage accountMessage = (AccountMessage) this.sendMessage(getAccountMessage, ACCOUNT);
+        if (accountMessage == null) {
+            return null;
+        }
+        return accountMessage.getAccountData();
+    }
+
+    /**
+     * Fetch account balance data from peers for given QORT address and asset ID
+     * @param address - the QORT address to query
+     * @return balance - the balance for this address and assetId, or null if not retrieved
+     */
+    public AccountBalanceData fetchAccountBalance(String address, long assetId) {
+        GetAccountBalanceMessage getAccountMessage = new GetAccountBalanceMessage(address, assetId);
+        AccountBalanceMessage accountMessage = (AccountBalanceMessage) this.sendMessage(getAccountMessage, ACCOUNT_BALANCE);
+        if (accountMessage == null) {
+            return null;
+        }
+        return accountMessage.getAccountBalanceData();
+    }
+
+
+    private Message sendMessage(Message message, MessageType expectedResponseMessageType) {
+        // This asks a random peer for the data
+        // TODO: ask multiple peers, and disregard everything if there are any significant differences in the responses
+
+        // Needs a mutable copy of the unmodifiableList
+        List<Peer> peers = new ArrayList<>(Network.getInstance().getImmutableHandshakedPeers());
+
+        // Disregard peers that have "misbehaved" recently
+        peers.removeIf(Controller.hasMisbehaved);
+
+        // Disregard peers that only have genesis block
+        peers.removeIf(Controller.hasOnlyGenesisBlock);
+
+        // Disregard peers that are on an old version
+        peers.removeIf(Controller.hasOldVersion);
+
+        // Disregard peers that are on a known inferior chain tip
+        peers.removeIf(Controller.hasInferiorChainTip);
+
+        if (peers.isEmpty()) {
+            LOGGER.info("No peers available to send {} message to", message.getType());
+            return null;
+        }
+
+        // Pick random peer
+        int index = new SecureRandom().nextInt(peers.size());
+        Peer peer = peers.get(index);
+
+        LOGGER.info("Sending {} message to peer {}...", message.getType(), peer);
+
+        Message responseMessage;
+
+        try {
+            responseMessage = peer.getResponse(message);
+
+        } catch (InterruptedException e) {
+            return null;
+        }
+
+        if (responseMessage == null || responseMessage.getType() != expectedResponseMessageType) {
+            return null;
+        }
+
+        LOGGER.info("Peer {} responded with {} message", peer, responseMessage.getType());
+
+        return responseMessage;
+    }
+
+}

src/main/java/org/qortal/network/message/AccountBalanceMessage.java

@@ -0,0 +1,78 @@
+package org.qortal.network.message;
+
+import com.google.common.primitives.Longs;
+import org.qortal.data.account.AccountBalanceData;
+import org.qortal.transform.Transformer;
+import org.qortal.utils.Base58;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+
+public class AccountBalanceMessage extends Message {
+
+	private static final int ADDRESS_LENGTH = Transformer.ADDRESS_LENGTH;
+
+	private final AccountBalanceData accountBalanceData;
+
+	public AccountBalanceMessage(AccountBalanceData accountBalanceData) {
+		super(MessageType.ACCOUNT_BALANCE);
+
+		this.accountBalanceData = accountBalanceData;
+	}
+
+	public AccountBalanceMessage(int id, AccountBalanceData accountBalanceData) {
+		super(id, MessageType.ACCOUNT_BALANCE);
+
+		this.accountBalanceData = accountBalanceData;
+	}
+
+	public AccountBalanceData getAccountBalanceData() {
+		return this.accountBalanceData;
+	}
+
+
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
+		byte[] addressBytes = new byte[ADDRESS_LENGTH];
+		byteBuffer.get(addressBytes);
+		String address = Base58.encode(addressBytes);
+
+		long assetId = byteBuffer.getLong();
+
+		long balance = byteBuffer.getLong();
+
+		AccountBalanceData accountBalanceData = new AccountBalanceData(address, assetId, balance);
+		return new AccountBalanceMessage(id, accountBalanceData);
+	}
+
+	@Override
+	protected byte[] toData() {
+		if (this.accountBalanceData == null) {
+			return null;
+		}
+
+		try {
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+			// Send raw address instead of base58 encoded
+			byte[] address = Base58.decode(this.accountBalanceData.getAddress());
+			bytes.write(address);
+
+			bytes.write(Longs.toByteArray(this.accountBalanceData.getAssetId()));
+
+			bytes.write(Longs.toByteArray(this.accountBalanceData.getBalance()));
+
+			return bytes.toByteArray();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
+	public AccountBalanceMessage cloneWithNewId(int newId) {
+		AccountBalanceMessage clone = new AccountBalanceMessage(this.accountBalanceData);
+		clone.setId(newId);
+		return clone;
+	}
+
+}

src/main/java/org/qortal/network/message/AccountMessage.java

@@ -0,0 +1,101 @@
+package org.qortal.network.message;
+
+import com.google.common.primitives.Ints;
+import org.qortal.data.account.AccountData;
+import org.qortal.transform.Transformer;
+import org.qortal.utils.Base58;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+
+public class AccountMessage extends Message {
+
+	private static final int ADDRESS_LENGTH = Transformer.ADDRESS_LENGTH;
+	private static final int REFERENCE_LENGTH = Transformer.SIGNATURE_LENGTH;
+	private static final int PUBLIC_KEY_LENGTH = Transformer.PUBLIC_KEY_LENGTH;
+
+	private final AccountData accountData;
+
+	public AccountMessage(AccountData accountData) {
+		super(MessageType.ACCOUNT);
+
+		this.accountData = accountData;
+	}
+
+	public AccountMessage(int id, AccountData accountData) {
+		super(id, MessageType.ACCOUNT);
+
+		this.accountData = accountData;
+	}
+
+	public AccountData getAccountData() {
+		return this.accountData;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer byteBuffer) throws UnsupportedEncodingException {
+		byte[] addressBytes = new byte[ADDRESS_LENGTH];
+		byteBuffer.get(addressBytes);
+		String address = Base58.encode(addressBytes);
+
+		byte[] reference = new byte[REFERENCE_LENGTH];
+		byteBuffer.get(reference);
+
+		byte[] publicKey = new byte[PUBLIC_KEY_LENGTH];
+		byteBuffer.get(publicKey);
+
+		int defaultGroupId = byteBuffer.getInt();
+
+		int flags = byteBuffer.getInt();
+
+		int level = byteBuffer.getInt();
+
+		int blocksMinted = byteBuffer.getInt();
+
+		int blocksMintedAdjustment = byteBuffer.getInt();
+
+		AccountData accountData = new AccountData(address, reference, publicKey, defaultGroupId, flags, level, blocksMinted, blocksMintedAdjustment);
+		return new AccountMessage(id, accountData);
+	}
+
+	@Override
+	protected byte[] toData() {
+		if (this.accountData == null) {
+			return null;
+		}
+
+		try {
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+			// Send raw address instead of base58 encoded
+			byte[] address = Base58.decode(accountData.getAddress());
+			bytes.write(address);
+
+			bytes.write(accountData.getReference());
+
+			bytes.write(accountData.getPublicKey());
+
+			bytes.write(Ints.toByteArray(accountData.getDefaultGroupId()));
+
+			bytes.write(Ints.toByteArray(accountData.getFlags()));
+
+			bytes.write(Ints.toByteArray(accountData.getLevel()));
+
+			bytes.write(Ints.toByteArray(accountData.getBlocksMinted()));
+
+			bytes.write(Ints.toByteArray(accountData.getBlocksMintedAdjustment()));
+
+			return bytes.toByteArray();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
+	public AccountMessage cloneWithNewId(int newId) {
+		AccountMessage clone = new AccountMessage(this.accountData);
+		clone.setId(newId);
+		return clone;
+	}
+
+}

src/main/java/org/qortal/network/message/GetAccountBalanceMessage.java

@@ -0,0 +1,65 @@
+package org.qortal.network.message;
+
+import com.google.common.primitives.Longs;
+import org.qortal.transform.Transformer;
+import org.qortal.utils.Base58;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+
+public class GetAccountBalanceMessage extends Message {
+
+	private static final int ADDRESS_LENGTH = Transformer.ADDRESS_LENGTH;
+
+	private String address;
+	private long assetId;
+
+	public GetAccountBalanceMessage(String address, long assetId) {
+		this(-1, address, assetId);
+	}
+
+	private GetAccountBalanceMessage(int id, String address, long assetId) {
+		super(id, MessageType.GET_ACCOUNT_BALANCE);
+
+		this.address = address;
+		this.assetId = assetId;
+	}
+
+	public String getAddress() {
+		return this.address;
+	}
+
+	public long getAssetId() {
+		return this.assetId;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+		byte[] addressBytes = new byte[ADDRESS_LENGTH];
+		bytes.get(addressBytes);
+		String address = Base58.encode(addressBytes);
+
+		long assetId = bytes.getLong();
+
+		return new GetAccountBalanceMessage(id, address, assetId);
+	}
+
+	@Override
+	protected byte[] toData() {
+		try {
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+			// Send raw address instead of base58 encoded
+			byte[] address = Base58.decode(this.address);
+			bytes.write(address);
+
+			bytes.write(Longs.toByteArray(this.assetId));
+
+			return bytes.toByteArray();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
+}

src/main/java/org/qortal/network/message/GetAccountMessage.java

@@ -0,0 +1,57 @@
+package org.qortal.network.message;
+
+import org.qortal.transform.Transformer;
+import org.qortal.utils.Base58;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+
+public class GetAccountMessage extends Message {
+
+	private static final int ADDRESS_LENGTH = Transformer.ADDRESS_LENGTH;
+
+	private String address;
+
+	public GetAccountMessage(String address) {
+		this(-1, address);
+	}
+
+	private GetAccountMessage(int id, String address) {
+		super(id, MessageType.GET_ACCOUNT);
+
+		this.address = address;
+	}
+
+	public String getAddress() {
+		return this.address;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+		if (bytes.remaining() != ADDRESS_LENGTH)
+			return null;
+
+		byte[] addressBytes = new byte[ADDRESS_LENGTH];
+		bytes.get(addressBytes);
+		String address = Base58.encode(addressBytes);
+
+		return new GetAccountMessage(id, address);
+	}
+
+	@Override
+	protected byte[] toData() {
+		try {
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+			// Send raw address instead of base58 encoded
+			byte[] address = Base58.decode(this.address);
+			bytes.write(address);
+
+			return bytes.toByteArray();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
+}

src/main/java/org/qortal/network/message/Message.java

@@ -99,7 +99,12 @@ public abstract class Message {
 		GET_TRADE_PRESENCES(141),
 		
 		ARBITRARY_METADATA(150),
-		GET_ARBITRARY_METADATA(151);
+		GET_ARBITRARY_METADATA(151),
+
+		ACCOUNT(160),
+		GET_ACCOUNT(161),
+		ACCOUNT_BALANCE(162),
+		GET_ACCOUNT_BALANCE(163);
 
 		public final int value;
 		public final Method fromByteBufferMethod;