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Payment channels: tweaks to the examples.

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Print wallet state at various points. Demonstrate disconnecting vs closing channels.
This commit is contained in:
Mike Hearn
2013-07-25 15:32:17 +02:00
parent cf4c469e6e
commit ce1d8315ea
2 changed files with 53 additions and 35 deletions
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79
examples/src/main/java/com/google/bitcoin/examples/ExamplePaymentChannelClient.java
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@@ -16,10 +16,7 @@
package com.google.bitcoin.examples;
import com.google.bitcoin.core.ECKey;
import com.google.bitcoin.core.NetworkParameters;
import com.google.bitcoin.core.Utils;
import com.google.bitcoin.core.Wallet;
import com.google.bitcoin.core.*;
import com.google.bitcoin.kits.WalletAppKit;
import com.google.bitcoin.params.TestNet3Params;
import com.google.bitcoin.protocols.channels.PaymentChannelClientConnection;
@@ -29,14 +26,17 @@ import com.google.bitcoin.utils.BriefLogFormatter;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.Uninterruptibles;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.IOException;
import java.math.BigInteger;
import java.net.InetSocketAddress;
import java.util.concurrent.CountDownLatch;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static com.google.bitcoin.core.Utils.CENT;
import static java.math.BigInteger.TEN;
import static java.math.BigInteger.ZERO;
/**
* Simple client that connects to the given host, opens a channel, and pays one cent.
@@ -44,7 +44,7 @@ import static java.util.concurrent.TimeUnit.MILLISECONDS;
public class ExamplePaymentChannelClient {
private static final org.slf4j.Logger log = LoggerFactory.getLogger(ExamplePaymentChannelClient.class);
private WalletAppKit appKit;
private final BigInteger maxAcceptableRequestedAmount;
private final BigInteger channelSize;
private final ECKey myKey;
private final NetworkParameters params;
@@ -55,7 +55,7 @@ public class ExamplePaymentChannelClient {
}
public ExamplePaymentChannelClient() {
maxAcceptableRequestedAmount = Utils.COIN;
channelSize = CENT;
myKey = new ECKey();
params = TestNet3Params.get();
}
@@ -77,6 +77,9 @@ public class ExamplePaymentChannelClient {
// We now have active network connections and a fully synced wallet.
// Add a new key which will be used for the multisig contract.
appKit.wallet().addKey(myKey);
appKit.wallet().allowSpendingUnconfirmedTransactions();
System.out.println(appKit.wallet());
// Create the object which manages the payment channels protocol, client side. Tell it where the server to
// connect to is, along with some reasonable network timeouts, the wallet and our temporary key. We also have
@@ -86,53 +89,69 @@ public class ExamplePaymentChannelClient {
// the wallet, then it'll re-use that one instead.
final int timeoutSecs = 15;
final InetSocketAddress server = new InetSocketAddress(host, 4242);
PaymentChannelClientConnection client = null;
while (client == null) {
try {
final String channelID = host;
client = new PaymentChannelClientConnection(
server, timeoutSecs, appKit.wallet(), myKey, maxAcceptableRequestedAmount, channelID);
} catch (ValueOutOfRangeException e) {
// We don't have enough money in our wallet yet. Wait and try again.
waitForSufficientBalance(maxAcceptableRequestedAmount);
}
}
waitForSufficientBalance(channelSize);
final String channelID = host;
// Do this twice as each one sends 1/10th of a bitcent 5 times, so to send a bitcent, we do it twice. This
// demonstrates resuming a channel that wasn't closed yet. It should close automatically once we run out
// of money on the channel.
log.info("Round one ...");
openAndSend(timeoutSecs, server, channelID);
log.info("Round two ...");
log.info(appKit.wallet().toString());
openAndSend(timeoutSecs, server, channelID);
log.info("Waiting ...");
Thread.sleep(60 * 60 * 1000); // 1 hour.
log.info("Stopping ...");
appKit.stopAndWait();
}
private void openAndSend(int timeoutSecs, InetSocketAddress server, String channelID) throws IOException, ValueOutOfRangeException, InterruptedException {
PaymentChannelClientConnection client = new PaymentChannelClientConnection(
server, timeoutSecs, appKit.wallet(), myKey, channelSize, channelID);
// Opening the channel requires talking to the server, so it's asynchronous.
final CountDownLatch latch = new CountDownLatch(1);
Futures.addCallback(client.getChannelOpenFuture(), new FutureCallback<PaymentChannelClientConnection>() {
@Override
public void onSuccess(PaymentChannelClientConnection client) {
// Success! We should be able to try making micropayments now. Try doing it 10 times.
for (int i = 0; i < 10; i++) {
// Success! We should be able to try making micropayments now. Try doing it 5 times.
for (int i = 0; i < 5; i++) {
try {
client.incrementPayment(Utils.CENT);
client.incrementPayment(CENT.divide(TEN));
} catch (ValueOutOfRangeException e) {
log.error("Failed to increment payment by a CENT, remaining value is {}", client.state().getValueRefunded());
System.exit(-3);
}
log.info("Successfully sent payment of one CENT, total remaining on channel is now {}", client.state().getValueRefunded());
Uninterruptibles.sleepUninterruptibly(500, MILLISECONDS);
}
// Now tell the server we're done so they should broadcast the final transaction and refund us what's
// left. If we never do this then eventually the server will time out and do it anyway and if the
// server goes away for longer, then eventually WE will time out and the refund tx will get broadcast
// by ourselves.
log.info("Closing channel!");
client.close();
if (client.state().getValueRefunded().equals(ZERO)) {
// Now tell the server we're done so they should broadcast the final transaction and refund us what's
// left. If we never do this then eventually the server will time out and do it anyway and if the
// server goes away for longer, then eventually WE will time out and the refund tx will get broadcast
// by ourselves.
log.info("Closing channel for good");
client.close();
} else {
// Just unplug from the server but leave the channel open so it can resume later.
client.disconnectWithoutChannelClose();
}
latch.countDown();
}
@Override
public void onFailure(Throwable throwable) {
log.error("Failed to open connection", throwable);
latch.countDown();
}
});
latch.await();
}
private void waitForSufficientBalance(BigInteger amount) {
// Not enough money in the wallet.
BigInteger amountPlusFee = amount.add(Wallet.SendRequest.DEFAULT_FEE_PER_KB);
ListenableFuture<BigInteger> balanceFuture = appKit.wallet().getBalanceFuture(amountPlusFee, Wallet.BalanceType.AVAILABLE);
// ESTIMATED because we don't really need to wait for confirmation.
ListenableFuture<BigInteger> balanceFuture = appKit.wallet().getBalanceFuture(amountPlusFee, Wallet.BalanceType.ESTIMATED);
if (!balanceFuture.isDone()) {
System.out.println("Please send " + Utils.bitcoinValueToFriendlyString(amountPlusFee) +
" BTC to " + myKey.toAddress(params));

9
examples/src/main/java/com/google/bitcoin/examples/ExamplePaymentChannelServer.java
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@@ -16,10 +16,7 @@
package com.google.bitcoin.examples;
import com.google.bitcoin.core.NetworkParameters;
import com.google.bitcoin.core.Sha256Hash;
import com.google.bitcoin.core.Utils;
import com.google.bitcoin.core.VerificationException;
import com.google.bitcoin.core.*;
import com.google.bitcoin.kits.WalletAppKit;
import com.google.bitcoin.params.TestNet3Params;
import com.google.bitcoin.protocols.channels.*;
@@ -62,9 +59,11 @@ public class ExamplePaymentChannelServer implements PaymentChannelServerListener
};
appKit.startAndWait();
System.out.println(appKit.wallet());
// We provide a peer group, a wallet, a timeout in seconds, the amount we require to start a channel and
// an implementation of HandlerFactory, which we just implement ourselves.
new PaymentChannelServerListener(appKit.peerGroup(), appKit.wallet(), 15, Utils.COIN, this).bindAndStart(4242);
new PaymentChannelServerListener(appKit.peerGroup(), appKit.wallet(), 15, Utils.CENT, this).bindAndStart(4242);
}
@Override