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Getting earlier transactions with pagination.

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This commit is contained in:
Brendon Duncan 2018-08-21 12:43:03 +12:00
commit 78f0ff28cd
2 changed files with 161 additions and 62 deletions
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183
src/js/services/wallet-history.service.js
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@ -7,32 +7,109 @@
.factory('walletHistoryService', walletHistoryService);
function walletHistoryService(configService, storageService, lodash, $log, txFormatService) {
// 8 Transactions fit on an iPhone Plus screen when in Wallet Details.
// Make it a little bit bigger so it doesn't have to load more immediately
var PAGE_SIZE = 50 / 1.5;
//var PAGE_SIZE = 50;
var PAGE_SIZE = 20; // For dev only
// How much to overlap on each end of the page, for mitigating inconsistent sort order.
var PAGE_OVERLAP_FRACTION = 0.5;
var PAGE_OVERLAP_FRACTION = 0.2;
var PAGE_OVERLAP = Math.floor(PAGE_SIZE * PAGE_OVERLAP_FRACTION);
// The amount of transactions in the new overlapping resultset that we already know about.
// If we know about at least this many, then there are probably no gaps.
var MIN_KNOWN_TX_OVERLAP = Math.floor(PAGE_OVERLAP * 0.5);
var SAFE_CONFIRMATIONS = 6;
var service = {
getCachedTxHistory: getCachedTxHistory,
updateTxHistoryByPage: updateTxHistoryByPage
updateLocalTxHistoryByPage: updateLocalTxHistoryByPage,
};
return service;
function addEarlyTransactions(walletId, cachedTxs, newTxs) {
var cachedTxIds = {};
cachedTxs.forEach(function forCachedTx(tx){
cachedTxIds[tx.txid] = true;
});
var someTransactionWereNew = false;
var overlappingTxsCount = 0;
newTxs.forEach(function forNewTx(tx){
if (cachedTxIds[tx.txid]) {
overlappingTxsCount++;
} else {
someTransactionWereNew = true;
cachedTxs.push(tx);
}
});
console.log('pagination Overlapping transactions:', overlappingTxsCount);
if (overlappingTxsCount >= MIN_KNOWN_TX_OVERLAP) { // We are good
if (someTransactionWereNew) {
console.log('pagination someTransactionsWereNew');
saveTxHistory(walletId, cachedTxs);
}
return cachedTxs;
} else {
// We might be missing some txs.
console.error('We might be missing some txs in the history.');
// Our history is wrong, so remove it - we could instead, try to fetch data that was not so early.
storageService.removeTxHistory(walletId, function onRemoveTxHistory(){});
return [];
}
}
function addLatestTransactions(cachedTxs, newTxs) {
}
// Only clear the cache once we have received new transactions from the server.
/**
* @param {function(err, txs)} cb - transactions is always an array, may be empty
*/
function fetchTxHistoryByPage(wallet, start, cb) {
var skip = Math.max(0, start - PAGE_OVERLAP);
var limit = PAGE_SIZE;
var opts = {
skip: skip,
limit: limit
};
wallet.getTxHistory(opts, function onTxHistory(err, txsFromServer) {
if (err) {
return cb(err, []);
}
if (txsFromServer.length === 0) {
return cb(null, []);
}
console.log('pagination Transactions fetched:', txsFromServer.length);
var processedTxs = processNewTxs(wallet, txsFromServer);
/*
if (getLatest) {
console.log('pagination Saving retrieved txs.');
saveTxHistory(wallet, processedTxs);
}
*/
return cb(null, processedTxs);
});
}
/**
* @param {string} walletId
* @param {function(error, txs)} cb
* @param {function(error, txs)} cb - txs is always an array, may be empty
*/
function getCachedTxHistory(walletId, cb) {
storageService.getTxHistory(walletId, function onGetTxHistory(err, txHistoryString){
if (err) {
return cb(err);
return cb(err, []);
}
if (!txHistoryString) {
return cb(null, txHistoryString);
return cb(null, []);
}
try {
@ -40,7 +117,7 @@
return cb(null, txHistory);
} catch (e) {
$log.error('Failed to parse tx history.', e);
return cb(e);
return cb(e, []);
}
});
}
@ -83,46 +160,64 @@
return processedTxs;
};
/**
* A small cache of up to the 50 most recent transactions
*/
function saveTxHistory(processedTxs, walletId) {
function saveTxHistory(walletId, processedTxs) {
console.log('pagination Saving transactions:', processedTxs.length);
storageService.setTxHistory(processedTxs, walletId, function onSetTxHistory(error){
// Looks like callback only gets called on error
$log.error('pagination Failed to save tx history.', error);
});
}
// Only clear the cache once we have received new transactions from the server.
function updateTxHistoryByPage(wallet, getLatest, flushCacheOnNew, cb) {
var skip = 0;
var limit = Math.floor(PAGE_SIZE * (1 + PAGE_OVERLAP_FRACTION));
var opts = {
skip: skip,
limit: limit
};
wallet.getTxHistory(opts, function onTxHistory(err, txsFromServer) {
if (err) {
return cb(err);
if (error) {
$log.error('pagination Failed to save tx history.', error);
} else {
console.log('pagination Save successful.');
}
if (!txsFromServer.length) {
return cb(null, []);
}
var processedTxs = processNewTxs(wallet, txsFromServer);
if (getLatest) {
console.log('pagination Saving retrieved txs.');
saveTxHistory(wallet, processedTxs);
}
return cb(null, processedTxs);
});
}
function updateLocalTxHistoryByPage(wallet, getLatest, flushCacheOnNew, cb) {
if (flushCacheOnNew) {
console.log('pagination Getting latest txs.');
fetchTxHistoryByPage(wallet, 0, function onFetchTxHistory(err, txs){
if (err) {
return cb(err, txs);
}
saveTxHistory(wallet.id, txs);
return cb(null, txs);
});
} else {
console.log('pagination Getting early txs.');
getCachedTxHistory(wallet.id, function onCachedHistory(err, cachedTxs){
if (err) {
$log.error('Failed to get cached tx history.', err);
return cb(err, []);
}
var start = getLatest ? 0 : cachedTxs.length;
console.log('pagination Transaction fetch start:', start);
fetchTxHistoryByPage(wallet, start, function onFetchHistory(err, fetchedTxs){
if (err) {
return cb(err);
}
if (fetchedTxs.length === 0) {
return cb(null, cachedTxs);
}
var txs = [];
if (getLatest) {
txs = addLatestTransactions(wallet.id, cachedTxs, fetchedTxs);
} else {
txs = addEarlyTransactions(wallet.id, cachedTxs, fetchedTxs);
}
return cb(null, txs);
});
});
}
}
}