dynamic fees

lib/blockchainexplorers/insight.js

@@ -105,6 +105,23 @@ Insight.prototype.getAddressActivity = function(addresses, cb) {
   });
 };
 
+Insight.prototype.estimateFee = function(nbBlocks, cb) {
+  var url = this.url + '/api/utils/estimatefee';
+  if (nbBlocks) {
+    url += '?nbBlocks=' + nbBlocks;
+  }
+
+  var args = {
+    method: 'GET',
+    url: url,
+  };
+
+  request(args, function(err, res, body) {
+    if (err || res.statusCode !== 200) return cb(err || res);
+    return cb(null, body.feePerKB);
+  });
+};
+
 Insight.prototype.initSocket = function() {
   var socket = io.connect(this.url, {
     'reconnection': true,

lib/server.js

@@ -605,13 +605,14 @@ WalletService.prototype.verifyMessageSignature = function(opts, cb) {
 };
 
 
-WalletService.prototype._getBlockchainExplorer = function(provider, network) {
+WalletService.prototype._getBlockchainExplorer = function(network) {
   if (!this.blockchainExplorer) {
     var opts = {};
     if (this.blockchainExplorerOpts && this.blockchainExplorerOpts[network]) {
       opts = this.blockchainExplorerOpts[network];
     }
-    opts.provider = provider;
+    // TODO: provider should be configurable
+    opts.provider = 'insight';
     opts.network = network;
     this.blockchainExplorer = new BlockchainExplorer(opts);
   }
@@ -636,7 +637,7 @@ WalletService.prototype._getUtxos = function(cb) {
     var addressToPath = _.indexBy(addresses, 'address'); // TODO : check performance
     var networkName = Bitcore.Address(addressStrs[0]).toObject().network;
 
-    var bc = self._getBlockchainExplorer('insight', networkName);
+    var bc = self._getBlockchainExplorer(networkName);
     bc.getUnspentUtxos(addressStrs, function(err, inutxos) {
       if (err) {
         log.error('Could not fetch unspent outputs', err);
@@ -765,6 +766,79 @@ WalletService.prototype.getBalance = function(opts, cb) {
   });
 };
 
+WalletService.prototype._sampleFeeLevels = function(network, points, cb) {
+  var self = this;
+
+  // TODO: cache blockexplorer data
+  async.map(points, function(p, next) {
+    var bc = self._getBlockchainExplorer(network);
+    bc.estimateFee(p, function(err, result) {
+      if (err) {
+        log.error('Error estimating fee', err);
+        return next(err);
+      }
+      return next(null, [p, result.feePerKB * 1e8]);
+    });
+  }, function(err, results) {
+    if (err) return cb(err);
+    return cb(null, _.zipObject(results));
+  });
+};
+
+/**
+ * Returns fee levels for the current state of the network.
+ * @param {Object} opts
+ * @param {string} [opts.network = 'livenet'] - The Bitcoin network to estimate fee levels from.
+ * @returns {Object} feeLevels - A list of fee levels & associated amount per kB in satoshi.
+ */
+WalletService.prototype.getFeeLevels = function(opts, cb) {
+  var self = this;
+
+  opts = opts || {};
+
+  var network = opts.network || 'livenet';
+  if (network != 'livenet' && network != 'testnet')
+    return cb(new ClientError('Invalid network'));
+
+  var levels = [{
+    name: 'emergency',
+    nbBlocks: 2,
+    modifier: 1.5,
+    defaultValue: 50000
+  }, {
+    name: 'priority',
+    nbBlocks: 2,
+    modifier: 1,
+    defaultValue: 20000
+  }, {
+    name: 'normal',
+    nbBlocks: 4,
+    modifier: 1,
+    defaultValue: 10000
+  }, {
+    name: 'economy',
+    nbBlocks: 4,
+    modifier: 0.5,
+    defaultValue: 5000
+  }, ];
+
+  var samplePoints = _.uniq(_.pluck(levels, 'nbBlocks'));
+  self._sampleFeeLevels(network, samplePoints, function(err, feeSamples) {
+    var values = _.zipObject(_.map(levels, function(level) {
+      var feePerKB;
+      if (err) {
+        feePerKB = level.defaultValue;
+      } else {
+        var sample = feeSamples[level.nbBlocks];
+        feePerKB = (sample <= 0) ? level.defaultValue : sample * level.modifier;
+      }
+      return [level.name, feePerKB]
+    }));
+
+    return cb(null, values);
+  });
+};
+
 WalletService.prototype._selectTxInputs = function(txp, cb) {
   var self = this;
 
@@ -1102,7 +1176,7 @@ WalletService.prototype._broadcastTx = function(txp, cb) {
   } catch (ex) {
     return cb(ex);
   }
-  var bc = this._getBlockchainExplorer('insight', txp.getNetworkName());
+  var bc = this._getBlockchainExplorer(txp.getNetworkName());
   bc.broadcast(raw, function(err, txid) {
     if (err) {
       log.error('Could not broadcast transaction', err);
@@ -1114,7 +1188,7 @@ WalletService.prototype._broadcastTx = function(txp, cb) {
 
 WalletService.prototype._checkTxInBlockchain = function(txp, cb) {
   var tx = txp.getBitcoreTx();
-  var bc = this._getBlockchainExplorer('insight', txp.getNetworkName());
+  var bc = this._getBlockchainExplorer(txp.getNetworkName());
   bc.getTransaction(tx.id, function(err, tx) {
     if (err) {
       log.error('Could not get transaction info', err);
@@ -1502,7 +1576,7 @@ WalletService.prototype.getTxHistory = function(opts, cb) {
     var addressStrs = _.pluck(addresses, 'address');
     var networkName = Bitcore.Address(addressStrs[0]).toObject().network;
 
-    var bc = self._getBlockchainExplorer('insight', networkName);
+    var bc = self._getBlockchainExplorer(networkName);
     async.parallel([
 
       function(next) {
@@ -1556,7 +1630,7 @@ WalletService.prototype.scan = function(opts, cb) {
   };
 
   function checkActivity(addresses, networkName, cb) {
-    var bc = self._getBlockchainExplorer('insight', networkName);
+    var bc = self._getBlockchainExplorer(networkName);
     bc.getAddressActivity(addresses, cb);
   };
 

test/blockchainexplorer.js

@@ -19,6 +19,7 @@ describe('Blockchain explorer', function() {
       exp.should.respondTo('getTransactions');
       exp.should.respondTo('getAddressActivity');
       exp.should.respondTo('getUnspentUtxos');
+      exp.should.respondTo('estimateFee');
       exp.should.respondTo('initSocket');
       var exp = new BlockchainExplorer({
         provider: 'insight',

test/integration/server.js

@@ -198,6 +198,14 @@ helpers.stubHistory = function(txs) {
   };
 };
 
+helpers.stubFeeLevels = function(levels) {
+  blockchainExplorer.estimateFee = function(nbBlocks, cb) {
+    return cb(null, {
+      feePerKB: levels[nbBlocks] / 1e8 || -1
+    });
+  };
+};
+
 helpers.stubAddressActivity = function(activeAddresses) {
   blockchainExplorer.getAddressActivity = function(addresses, cb) {
     return cb(null, _.intersection(activeAddresses, addresses).length > 0);
@@ -1443,6 +1451,58 @@ describe('Wallet service', function() {
     });
   });
 
+  describe('#getFeeLevels', function() {
+    var server, wallet;
+    beforeEach(function(done) {
+      helpers.createAndJoinWallet(1, 1, function(s, w) {
+        server = s;
+        wallet = w;
+        done();
+      });
+    });
+
+    it('should get current fee levels', function(done) {
+      helpers.stubFeeLevels({
+        2: 40000,
+        4: 20000,
+        6: 18000,
+      });
+      server.getFeeLevels({}, function(err, fees) {
+        should.not.exist(err);
+        fees.emergency.should.equal(60000);
+        fees.priority.should.equal(40000);
+        fees.normal.should.equal(20000);
+        fees.economy.should.equal(10000);
+        done();
+      });
+    });
+    it('should get default fees if network cannot be accessed', function(done) {
+      blockchainExplorer.estimateFee = sinon.stub().yields('dummy error');
+      server.getFeeLevels({}, function(err, fees) {
+        should.not.exist(err);
+        fees.emergency.should.equal(50000);
+        fees.priority.should.equal(20000);
+        fees.normal.should.equal(10000);
+        fees.economy.should.equal(5000);
+        done();
+      });
+    });
+    it('should get default fees if network cannot estimate (returns -1)', function(done) {
+      helpers.stubFeeLevels({
+        2: -1,
+        4: 18000,
+      });
+      server.getFeeLevels({}, function(err, fees) {
+        should.not.exist(err);
+        fees.emergency.should.equal(50000);
+        fees.priority.should.equal(20000);
+        fees.normal.should.equal(18000);
+        fees.economy.should.equal(9000);
+        done();
+      });
+    });
+  });
+
   describe('Wallet not complete tests', function() {
     it('should fail to create address when wallet is not complete', function(done) {
       var server = new WalletService();