/*
* Copyright 2013 Google Inc.
* Copyright 2014 Andreas Schildbach
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.bitcoinj.examples;
import joptsimple.OptionParser;
import joptsimple.OptionSet;
import joptsimple.OptionSpec;
import org.bitcoinj.core.*;
import org.bitcoinj.kits.WalletAppKit;
import org.bitcoinj.params.RegTestParams;
import org.bitcoinj.protocols.channels.*;
import org.bitcoinj.utils.BriefLogFormatter;
import org.bitcoinj.utils.Threading;
import org.bitcoinj.wallet.Wallet;
import org.bitcoinj.wallet.WalletExtension;
import com.google.common.collect.ImmutableList;
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.net.InetSocketAddress;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import static org.bitcoinj.core.Coin.CENT;
/**
* Simple client that connects to the given host, opens a channel, and pays one cent.
*/
public class ExamplePaymentChannelClient {
private static final org.slf4j.Logger log = LoggerFactory.getLogger(ExamplePaymentChannelClient.class);
private WalletAppKit appKit;
private final Coin channelSize;
private final ECKey myKey;
private final NetworkParameters params;
public static void main(String[] args) throws Exception {
BriefLogFormatter.init();
OptionParser parser = new OptionParser();
OptionSpec<NetworkEnum> net = parser.accepts("net", "The network to run the examples on").withRequiredArg().ofType(NetworkEnum.class).defaultsTo(NetworkEnum.TEST);
OptionSpec<Integer> version = parser.accepts("version", "The payment channel protocol to use").withRequiredArg().ofType(Integer.class);
parser.accepts("help", "Displays program options");
OptionSet opts = parser.parse(args);
if (opts.has("help") || !opts.has(net) || opts.nonOptionArguments().size() != 1) {
System.err.println("usage: ExamplePaymentChannelClient --net=MAIN/TEST/REGTEST --version=1/2 host");
parser.printHelpOn(System.err);
return;
}
IPaymentChannelClient.ClientChannelProperties clientChannelProperties = new PaymentChannelClient.DefaultClientChannelProperties(){
@Override
public PaymentChannelClient.VersionSelector versionSelector() { return PaymentChannelClient.VersionSelector.VERSION_1; }
};
if (opts.has("version")) {
switch (version.value(opts)) {
case 1:
// Keep the default
break;
case 2:
clientChannelProperties = new PaymentChannelClient.DefaultClientChannelProperties(){
@Override
public PaymentChannelClient.VersionSelector versionSelector() { return PaymentChannelClient.VersionSelector.VERSION_2; }
};
break;
default:
System.err.println("Invalid version - valid versions are 1, 2");
return;
}
}
NetworkParameters params = net.value(opts).get();
new ExamplePaymentChannelClient().run(opts.nonOptionArguments().get(0), clientChannelProperties, params);
}
public ExamplePaymentChannelClient() {
channelSize = CENT;
myKey = new ECKey();
params = RegTestParams.get();
}
public void run(final String host, IPaymentChannelClient.ClientChannelProperties clientChannelProperties, final NetworkParameters params) throws Exception {
// Bring up all the objects we need, create/load a wallet, sync the chain, etc. We override WalletAppKit so we
// can customize it by adding the extension objects - we have to do this before the wallet file is loaded so
// the plugin that knows how to parse all the additional data is present during the load.
appKit = new WalletAppKit(params, new File("."), "payment_channel_example_client") {
@Override
protected List<WalletExtension> provideWalletExtensions() {
// The StoredPaymentChannelClientStates object is responsible for, amongst other things, broadcasting
// the refund transaction if its lock time has expired. It also persists channels so we can resume them
// after a restart.
// We should not send a PeerGroup in the StoredPaymentChannelClientStates constructor
// since WalletAppKit will find it for us.
return ImmutableList.<WalletExtension>of(new StoredPaymentChannelClientStates(null));
}
};
// Broadcasting can take a bit of time so we up the timeout for "real" networks
final int timeoutSeconds = params.getId().equals(NetworkParameters.ID_REGTEST) ? 15 : 150;
if (params == RegTestParams.get()) {
appKit.connectToLocalHost();
}
appKit.startAsync();
appKit.awaitRunning();
// 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().importKey(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
// to pick an amount of value to lock up for the duration of the channel.
//
// Note that this may or may not actually construct a new channel. If an existing unclosed channel is found in
// the wallet, then it'll re-use that one instead.
final InetSocketAddress server = new InetSocketAddress(host, 4242);
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(timeoutSeconds, server, channelID, 5, clientChannelProperties);
log.info("Round two ...");
log.info(appKit.wallet().toString());
openAndSend(timeoutSeconds, server, channelID, 4, clientChannelProperties); // 4 times because the opening of the channel made a payment.
log.info("Stopping ...");
appKit.stopAsync();
appKit.awaitTerminated();
}
private void openAndSend(int timeoutSecs, InetSocketAddress server, String channelID, final int times, IPaymentChannelClient.ClientChannelProperties clientChannelProperties) throws IOException, ValueOutOfRangeException, InterruptedException {
// Use protocol version 1 for simplicity
PaymentChannelClientConnection client = new PaymentChannelClientConnection(
server, timeoutSecs, appKit.wallet(), myKey, channelSize, channelID, null, clientChannelProperties);
// 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) {
// By the time we get here, if the channel is new then we already made a micropayment! The reason is,
// we are not allowed to have payment channels that pay nothing at all.
log.info("Success! Trying to make {} micropayments. Already paid {} satoshis on this channel",
times, client.state().getValueSpent());
final Coin MICROPAYMENT_SIZE = CENT.divide(10);
for (int i = 0; i < times; i++) {
try {
// Wait because the act of making a micropayment is async, and we're not allowed to overlap.
// This callback is running on the user thread (see the last lines in openAndSend) so it's safe
// for us to block here: if we didn't select the right thread, we'd end up blocking the payment
// channels thread and would deadlock.
Uninterruptibles.getUninterruptibly(client.incrementPayment(MICROPAYMENT_SIZE));
} catch (ValueOutOfRangeException e) {
log.error("Failed to increment payment by a CENT, remaining value is {}", client.state().getValueRefunded());
throw new RuntimeException(e);
} catch (ExecutionException e) {
log.error("Failed to increment payment", e);
throw new RuntimeException(e);
}
log.info("Successfully sent payment of one CENT, total remaining on channel is now {}", client.state().getValueRefunded());
}
if (client.state().getValueRefunded().compareTo(MICROPAYMENT_SIZE) < 0) {
// 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("Settling channel for good");
client.settle();
} else {
// Just unplug from the server but leave the channel open so it can resume later.
client.disconnectWithoutSettlement();
}
latch.countDown();
}
@Override
public void onFailure(Throwable throwable) {
log.error("Failed to open connection", throwable);
latch.countDown();
}
}, Threading.USER_THREAD);
latch.await();
}
private void waitForSufficientBalance(Coin amount) {
// Not enough money in the wallet.
Coin amountPlusFee = amount.add(Transaction.REFERENCE_DEFAULT_MIN_TX_FEE);
// ESTIMATED because we don't really need to wait for confirmation.
ListenableFuture<Coin> balanceFuture = appKit.wallet().getBalanceFuture(amountPlusFee, Wallet.BalanceType.ESTIMATED);
if (!balanceFuture.isDone()) {
System.out.println("Please send " + amountPlusFee.toFriendlyString() +
" to " + myKey.toAddress(params));
Futures.getUnchecked(balanceFuture);
}
}
}