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Refactoring exchange rate lookup
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@hank
hank committed Mar 17, 2014
1 parent 4c41bb0 commit e2b7026
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Showing 5 changed files with 266 additions and 211 deletions.
228 changes: 17 additions & 211 deletions wallet/src/de/schildbach/wallet/ExchangeRatesProvider.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
Expand All @@ -31,22 +30,17 @@
import java.util.Locale;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.annotation.CheckForNull;
import javax.annotation.Nonnull;

import android.util.Log;
import de.schildbach.wallet.Constants;
import de.schildbach.wallet.exchange.GoogleRateLookup;
import de.schildbach.wallet.exchange.RateLookup;
import de.schildbach.wallet.exchange.YahooRateLookup;
import de.schildbach.wallet.util.GenericUtils;
import de.schildbach.wallet.util.Io;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.database.Cursor;
Expand Down Expand Up @@ -94,16 +88,18 @@ public String toString()
private static final String[] BTCE_FIELDS = new String[] { "avg" };
private static final URL BTCE_EURO_URL;
private static final String[] BTCE_EURO_FIELDS = new String[] { "avg" };
private static final URL VIRCUREX_URL;
private static final String[] VIRCUREX_FIELDS = new String[] { "value" };
private static final URL KRAKEN_URL;
private static final URL KRAKEN_EURO_URL;
private static final String[] KRAKEN_FIELDS = new String[] { "value" };

static
{
try
{
BTCE_URL = new URL("https://btc-e.com/api/2/ltc_usd/ticker");
BTCE_EURO_URL = new URL("https://btc-e.com/api/2/ltc_eur/ticker");
VIRCUREX_URL = new URL("https://api.vircurex.com/api/get_last_trade.json?base=LTC&alt=USD");
KRAKEN_URL = new URL("https://api.kraken.com/0/public/Ticker?pair=XLTCZUSD");
KRAKEN_EURO_URL = new URL("https://api.kraken.com/0/public/Ticker?pair=XLTCZEUR");
}
catch (final MalformedURLException x)
{
Expand Down Expand Up @@ -138,10 +134,12 @@ public Cursor query(final Uri uri, final String[] projection, final String selec
if (exchangeRates == null)
newExchangeRates = requestExchangeRates(BTCE_URL, "USD", BTCE_FIELDS);
if (exchangeRates == null && newExchangeRates == null)
newExchangeRates = requestExchangeRates(VIRCUREX_URL, "USD", VIRCUREX_FIELDS);
newExchangeRates = requestExchangeRates(KRAKEN_URL, "USD", KRAKEN_FIELDS);

// Get Euro rates as a fallback if Yahoo! fails below
Map<String, ExchangeRate> euroRate = requestExchangeRates(BTCE_EURO_URL, "EUR", BTCE_EURO_FIELDS);
if (euroRate == null)
euroRate = requestExchangeRates(KRAKEN_EURO_URL, "EUR", KRAKEN_FIELDS);
if(euroRate != null) {
if(newExchangeRates != null)
newExchangeRates.putAll(euroRate);
Expand All @@ -151,16 +149,18 @@ public Cursor query(final Uri uri, final String[] projection, final String selec

if (newExchangeRates != null)
{
// Get USD conversion exchange rates from Google
// Get USD conversion exchange rates from Google/Yahoo
ExchangeRate usdRate = newExchangeRates.get("USD");
RateProvider providers[] = {new GoogleRatesProvider(), new YahooRatesProvider()};
RateLookup providers[] = {new GoogleRateLookup(), new YahooRateLookup()};
Map<String, ExchangeRate> fiatRates;
for(RateProvider provider : providers) {
for(RateLookup provider : providers) {
fiatRates = provider.getRates(usdRate);
if(fiatRates != null) {
// Remove EUR if we have a better source above
if(euroRate != null)
fiatRates.remove("EUR");
// Remove USD rate because we already have it
fiatRates.remove("USD");
newExchangeRates.putAll(fiatRates);
break;
}
Expand Down Expand Up @@ -291,7 +291,7 @@ private static Map<String, ExchangeRate> requestExchangeRates(final URL url, fin
{
try
{
final BigInteger rate = GenericUtils.toNanoCoins(rateStr, 0);
final BigInteger rate = GenericUtils.toNanoCoinsRounded(rateStr, 0);

if (rate.signum() > 0)
{
Expand Down Expand Up @@ -341,198 +341,4 @@ private static Map<String, ExchangeRate> requestExchangeRates(final URL url, fin

return null;
}

abstract class RateProvider {
abstract Map<String, ExchangeRate> getRates(ExchangeRate usdRate);
}

class GoogleRatesProvider extends RateProvider {
public Map<String, ExchangeRate> getRates(ExchangeRate usdRate) {
URL url = null;
final BigDecimal decUsdRate = GenericUtils.fromNanoCoins(usdRate.rate, 0);
try {
url = new URL("http://spreadsheets.google.com/feeds/list/0Av2v4lMxiJ1AdE9laEZJdzhmMzdmcW90VWNfUTYtM2c/2/public/basic?alt=json");
} catch(MalformedURLException e) {
Log.i(ExchangeRatesProvider.TAG, "Failed to parse Google Spreadsheets URL");
return null;
}
HttpURLConnection connection = null;
Reader reader = null;

try
{
connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(Constants.HTTP_TIMEOUT_MS);
connection.setReadTimeout(Constants.HTTP_TIMEOUT_MS);
connection.connect();

final int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK)
{
reader = new InputStreamReader(new BufferedInputStream(connection.getInputStream(), 1024), Constants.UTF_8);
final StringBuilder content = new StringBuilder();
Io.copy(reader, content);

final Map<String, ExchangeRate> rates = new TreeMap<String, ExchangeRate>();
JSONObject head = new JSONObject(content.toString());
JSONArray resultArray;

try {
head = head.getJSONObject("feed");
resultArray = head.getJSONArray("entry");
// Format: eg. _cpzh4: 3.673
Pattern p = Pattern.compile("_cpzh4: ([\\d\\.]+)");
for(int i = 0; i < resultArray.length(); ++i) {
String currencyCd = resultArray.getJSONObject(i).getJSONObject("title").getString("$t");
String rateStr = resultArray.getJSONObject(i).getJSONObject("content").getString("$t");
Matcher m = p.matcher(rateStr);
if(m.matches())
{
// Just get the good part
rateStr = m.group(1);
Log.d(ExchangeRatesProvider.TAG, "Currency: " + currencyCd);
Log.d(ExchangeRatesProvider.TAG, "Rate: " + rateStr);
Log.d(ExchangeRatesProvider.TAG, "USD Rate: " + decUsdRate.toString());
BigDecimal rate = new BigDecimal(rateStr);
Log.d(ExchangeRatesProvider.TAG, "Converted Rate: " + rate.toString());
rate = decUsdRate.multiply(rate);
Log.d(ExchangeRatesProvider.TAG, "Final Rate: " + rate.toString());
if (rate.signum() > 0)
{
rates.put(currencyCd, new ExchangeRate(currencyCd,
GenericUtils.toNanoCoins(rate.toString(), 0), url.getHost()));
}
}
}
} catch(JSONException e) {
Log.i(ExchangeRatesProvider.TAG, "Bad JSON response from Google Spreadsheets!: " + content.toString());
return null;
}
return rates;
} else {
Log.i(ExchangeRatesProvider.TAG, "Bad response code from Google Spreadsheets!: " + responseCode);
}
}
catch (final Exception x)
{
Log.w(ExchangeRatesProvider.TAG, "Problem fetching exchange rates", x);
}
finally
{
if (reader != null)
{
try
{
reader.close();
}
catch (final IOException x)
{
// swallow
}
}

if (connection != null)
connection.disconnect();
}
return null;
}
}

class YahooRatesProvider extends RateProvider{
public Map<String, ExchangeRate> getRates(ExchangeRate usdRate) {
// Fetch all the currencies from Yahoo!
URL url = null;
final BigDecimal decUsdRate = GenericUtils.fromNanoCoins(usdRate.rate, 0);
try {
// TODO: make this look less crappy and make it easier to add currencies.
url = new URL("http://query.yahooapis.com/v1/public/yql?q=select%20id%2C%20Rate%20from%20yahoo.finance.xchange" +
"%20where%20pair%20in%20(%22USDEUR%22%2C%20%22USDJPY%22%2C%20%22USDBGN%22%2C%20%22USDCZK%22%2C%20" +
"%22USDDKK%22%2C%20%22USDGBP%22%2C%20%22USDHUF%22%2C%20%22USDLTL%22%2C%20%22USDLVL%22%2C%20%22USDPLN" +
"%22%2C%20%22USDRON%22%2C%20%22USDSEK%22%2C%20%22USDCHF%22%2C%20%22USDNOK%22%2C%20%22USDHRK%22%2C%20" +
"%22USDRUB%22%2C%20%22USDTRY%22%2C%20%22USDAUD%22%2C%20%22USDBRL%22%2C%20%22USDCAD%22%2C%20%22USDCNY" +
"%22%2C%20%22USDHKD%22%2C%20%22USDIDR%22%2C%20%22USDILS%22%2C%20%22USDINR%22%2C%20%22USDKRW%22%2C%20" +
"%22USDMXN%22%2C%20%22USDMYR%22%2C%20%22USDNZD%22%2C%20%22USDPHP%22%2C%20%22USDSGD%22%2C%20%22USDTHB" +
"%22%2C%20%22USDZAR%22%2C%20%22USDISK%22)&format=json&env=store%3A%2F%2Fdatatables.org" +
"%2Falltableswithkeys&callback=");
} catch (MalformedURLException e) {
Log.i(ExchangeRatesProvider.TAG, "Failed to parse Yahoo! Finance URL");
return null;
}

HttpURLConnection connection = null;
Reader reader = null;

try
{
connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(Constants.HTTP_TIMEOUT_MS);
connection.setReadTimeout(Constants.HTTP_TIMEOUT_MS);
connection.connect();

final int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK)
{
reader = new InputStreamReader(new BufferedInputStream(connection.getInputStream(), 1024), Constants.UTF_8);
final StringBuilder content = new StringBuilder();
Io.copy(reader, content);

final Map<String, ExchangeRate> rates = new TreeMap<String, ExchangeRate>();
JSONObject head = new JSONObject(content.toString());
JSONArray resultArray;
try {
head = head.getJSONObject("query");
head = head.getJSONObject("results");
resultArray = head.getJSONArray("rate");
} catch(JSONException e) {
Log.i(ExchangeRatesProvider.TAG, "Bad JSON response from Yahoo!: " + content.toString());
return null;
}
for(int i = 0; i < resultArray.length(); ++i) {
final JSONObject rateObj = resultArray.getJSONObject(i);
String currencyCd = rateObj.getString("id").substring(3);
Log.d(ExchangeRatesProvider.TAG, "Currency: " + currencyCd);
String rateStr = rateObj.getString("Rate");
Log.d(ExchangeRatesProvider.TAG, "Rate: " + rateStr);
Log.d(ExchangeRatesProvider.TAG, "USD Rate: " + decUsdRate.toString());
BigDecimal rate = new BigDecimal(rateStr);
Log.d(ExchangeRatesProvider.TAG, "Converted Rate: " + rate.toString());
rate = decUsdRate.multiply(rate);
Log.d(ExchangeRatesProvider.TAG, "Final Rate: " + rate.toString());
if (rate.signum() > 0)
{
rates.put(currencyCd, new ExchangeRate(currencyCd,
GenericUtils.toNanoCoins(rate.toString(), 0), url.getHost()));
}
}
Log.i(ExchangeRatesProvider.TAG, "Fetched exchange rates from " + url);
return rates;
} else {
Log.i(ExchangeRatesProvider.TAG, "Bad response code from Yahoo!: " + responseCode);
}
}
catch (final Exception x)
{
Log.w(ExchangeRatesProvider.TAG, "Problem fetching exchange rates", x);
}
finally
{
if (reader != null)
{
try
{
reader.close();
}
catch (final IOException x)
{
// swallow
}
}

if (connection != null)
connection.disconnect();
}

return null;
}
}
}
70 changes: 70 additions & 0 deletions wallet/src/de/schildbach/wallet/exchange/GoogleRateLookup.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,70 @@
package de.schildbach.wallet.exchange;

import android.util.Log;
import de.schildbach.wallet.ExchangeRatesProvider;
import de.schildbach.wallet.util.GenericUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.math.BigDecimal;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class GoogleRateLookup extends RateLookup {
private static final String TAG = GoogleRateLookup.class.getName();

public GoogleRateLookup()
{
super("http://spreadsheets.google.com/feeds/list/0Av2v4lMxiJ1AdE9laEZJdzhmMzdmcW90VWNfUTYtM2c/2/public/basic?alt=json");
}

public Map<String, ExchangeRatesProvider.ExchangeRate> getRates(ExchangeRatesProvider.ExchangeRate usdRate) {
final BigDecimal decUsdRate = GenericUtils.fromNanoCoins(usdRate.rate, 0);
if(getData())
{
// We got data from the HTTP connection
final Map<String, ExchangeRatesProvider.ExchangeRate> rates =
new TreeMap<String, ExchangeRatesProvider.ExchangeRate>();
try
{
JSONObject head = new JSONObject(this.data);
JSONArray resultArray;

head = head.getJSONObject("feed");
resultArray = head.getJSONArray("entry");
// Format: eg. _cpzh4: 3.673
Pattern p = Pattern.compile("_cpzh4: ([\\d\\.]+)");
for(int i = 0; i < resultArray.length(); ++i) {
String currencyCd = resultArray.getJSONObject(i).getJSONObject("title").getString("$t");
String rateStr = resultArray.getJSONObject(i).getJSONObject("content").getString("$t");
Matcher m = p.matcher(rateStr);
if(m.matches())
{
// Just get the good part
rateStr = m.group(1);
Log.d(TAG, "Currency: " + currencyCd);
Log.d(TAG, "Rate: " + rateStr);
Log.d(TAG, "USD Rate: " + decUsdRate.toString());
BigDecimal rate = new BigDecimal(rateStr);
Log.d(TAG, "Converted Rate: " + rate.toString());
rate = decUsdRate.multiply(rate);
Log.d(TAG, "Final Rate: " + rate.toString());
if (rate.signum() > 0)
{
rates.put(currencyCd, new ExchangeRatesProvider.ExchangeRate(currencyCd,
GenericUtils.toNanoCoinsRounded(rate.toString(), 0), this.url.getHost()));
}
}
}
} catch(JSONException e) {
Log.i(TAG, "Bad JSON response from Google Spreadsheets!: " + data);
return null;
}
return rates;
}
return null;
}
}
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