Intro

We use Web3j java library to work with Ethereum network. I use Rinkeby test network wit Geth client at the moment. I got familiar with blockchains only a week ago, so terms I use can be incorrect.

Brief

Almost all required features are clear for me except transactions history. I've stucked at this point. What I have now is two test methods.

• First piece looks up through all history by do post filtering, so it requires a lot of time to get result.

    @Test
    public void testReplayTransactions() throws Exception {
        EthBlock earliestBlockResponse = web3j.ethGetBlockByNumber(DefaultBlockParameterName.EARLIEST, false).send();
        EthBlock.Block earliestBlock = earliestBlockResponse.getBlock();
        LOGGER.info("EARLIEST block number: {}", earliestBlock.getNumber());
  
        EthBlock latestBlockResponse  = web3j.ethGetBlockByNumber(DefaultBlockParameterName.LATEST, false).send();
        EthBlock.Block latestBlock = latestBlockResponse.getBlock();
        LOGGER.info("LATEST block number: {}", latestBlock.getNumber());
  
        DefaultBlockParameter startBlock = DefaultBlockParameter.valueOf(latestBlock.getNumber().subtract(BigInteger.valueOf(1000)));
        DefaultBlockParameter endBlock = DefaultBlockParameter.valueOf(latestBlock.getNumber());
        //DefaultBlockParameter startBlock = DefaultBlockParameter.valueOf(earliestBlock.getNumber());
        //DefaultBlockParameter endBlock = DefaultBlockParameter.valueOf(earliestBlock.getNumber().add(BigInteger.valueOf(100000)));
  
        Subscription subscription = web3j
            .catchUpToLatestTransactionObservable(DefaultBlockParameterName.EARLIEST)
        //.replayTransactionsObservable(startBlock, endBlock)
            .filter(transaction -> {
                return KnownPeers.initialPeer.getAddress().equals(transaction.getFrom())
                    || KnownPeers.initialPeer.getAddress().equals(transaction.getTo());
            })
            .doOnError(throwable -> LOGGER.error("Error occurred", throwable))
            .doOnCompleted(() -> LOGGER.info("Completed"))
            .doOnEach(notification -> LOGGER.info("OnEach"))
            .subscribe(transaction -> {
                LOGGER.info("Transaction {} of block {}. From {} to {}",
                    transaction.getHash(),
                    transaction.getBlockNumber(),
                    transaction.getFrom(),
                    transaction.getTo());
            });
  
        Thread.sleep(10000);
        subscription.unsubscribe();
    }
  

• The next one queries for logs, but nothing returned in the first few seconds. So I guess either it also looks at all transactions or logs are something other.

    @Test
    public void getLogs() throws Exception {
        PeerInfo peerInfo = KnownPeers.initialPeer;
        EthFilter filter = new EthFilter(
            DefaultBlockParameterName.EARLIEST,
            DefaultBlockParameterName.LATEST,
            Arrays.asList(peerInfo.getAddress())
        );
  
        LOGGER.info("Start fetching logs");
        Subscription subscription = web3j
            .ethLogObservable(filter)
            .doOnError(throwable -> LOGGER.error("Error occurred", throwable))
            .subscribe(log -> {
                LOGGER.info("Transaction {} of block {}. From {} to {}",
                    log.getTransactionHash(),
                    log.getBlockNumber(),
                    log.getAddress(),
                    log.getType());
            });
  
        Thread.sleep(100000);
        subscription.unsubscribe();
    }
  

Found links

• Script To Find Transactions To/From An Account - JS way, but I need Java
• Getting transaction history for a particular account - JS way.
• Official REST API? - some REST API. Not sure what is this. It seems to be an official API of main network, but I need Web3j solution. It may act as a workaround, but not desired. Also not clear hot use it with test networks (Rinkeby)

Question

How fetch all transactions for an account quickly. Maybe not all, but 10-20 at once. Max timeout - less than 1-2 secs. This resource can do it.