implement variable fee per kb

lib/model/txproposal.js

@@ -37,6 +37,7 @@ TxProposal.create = function(opts) {
   x.outputOrder = _.shuffle(_.range(2));
   x.fee = null;
   x.network = Bitcore.Address(x.toAddress).toObject().network;
+  x.feePerKb = opts.feePerKb;
 
   return x;
 };
@@ -68,6 +69,7 @@ TxProposal.fromObj = function(obj) {
   x.outputOrder = obj.outputOrder;
   x.fee = obj.fee;
   x.network = obj.network;
+  x.feePerKb = obj.feePerKb;
 
   return x;
 };

lib/server.js

@@ -693,8 +693,6 @@ WalletService.prototype.getBalance = function(opts, cb) {
 WalletService.prototype._selectTxInputs = function(txp, cb) {
   var self = this;
 
-  Bitcore.Transaction.FEE_SECURITY_MARGIN = 1;
-
   self._getUtxos(function(err, utxos) {
     if (err) return cb(err);
 
@@ -730,6 +728,7 @@ WalletService.prototype._selectTxInputs = function(txp, cb) {
           if (!bitcoreError) {
             txp.inputPaths = _.pluck(txp.inputs, 'path');
             txp.fee = bitcoreTx.getFee();
+            $.checkState(txp.fee < 1e8, 'Fees are too high!');
             return cb();
           }
         } catch (ex) {
@@ -787,7 +786,8 @@ WalletService.prototype._canCreateTx = function(copayerId, cb) {
  * @param {number} opts.amount - Amount to transfer in satoshi.
  * @param {string} opts.message - A message to attach to this transaction.
  * @param {string} opts.proposalSignature - S(toAddress|amount|message|payProUrl). Used by other copayers to verify the proposal.
- * @param {string} opts.payProUrl - Options: Paypro URL for peers to verify TX
+ * @param {string} opts.feePerKb - Optional: Use an alternative fee per KB for this TX
+ * @param {string} opts.payProUrl - Optional: Paypro URL for peers to verify TX
  * @returns {TxProposal} Transaction proposal.
  */
 WalletService.prototype.createTx = function(opts, cb) {
@@ -796,6 +796,10 @@ WalletService.prototype.createTx = function(opts, cb) {
   if (!Utils.checkRequired(opts, ['toAddress', 'amount', 'proposalSignature']))
     return cb(new ClientError('Required argument missing'));
 
+  var feePerKb = opts.feePerKb || 10000;
+  if (!_.contains([1000, 5000, 10000], feePerKb))
+    return cb(new ClientError('Invalid fee per KB value'));
+
   self._runLocked(cb, function(cb) {
     self.getWallet({}, function(err, wallet) {
       if (err) return cb(err);
@@ -827,7 +831,6 @@ WalletService.prototype.createTx = function(opts, cb) {
         if (opts.amount < Bitcore.Transaction.DUST_AMOUNT)
           return cb(new ClientError('DUSTAMOUNT', 'Amount below dust threshold'));
 
-
         var changeAddress = wallet.createAddress(true);
 
         var txp = Model.TxProposal.create({
@@ -837,6 +840,7 @@ WalletService.prototype.createTx = function(opts, cb) {
           amount: opts.amount,
           message: opts.message,
           proposalSignature: opts.proposalSignature,
+          feePerKb: feePerKb,
           payProUrl: opts.payProUrl,
           changeAddress: changeAddress,
           requiredSignatures: wallet.m,

test/integration/server.js

@@ -184,13 +184,15 @@ helpers.stubAddressActivity = function(activeAddresses) {
 
 helpers.clientSign = WalletUtils.signTxp;
 
-helpers.createProposalOpts = function(toAddress, amount, message, signingKey) {
+helpers.createProposalOpts = function(toAddress, amount, message, signingKey, feePerKb) {
   var opts = {
     toAddress: toAddress,
     amount: helpers.toSatoshi(amount),
     message: message,
     proposalSignature: null,
   };
+  if (feePerKb) opts.feePerKb = feePerKb;
+
   var hash = WalletUtils.getProposalHash(opts.toAddress, opts.amount, opts.message);
   try {
     opts.proposalSignature = WalletUtils.signMessage(hash, signingKey);
@@ -1431,6 +1433,30 @@ describe('Wallet service', function() {
       });
     });
 
+    it('should be possible to use a smaller fee', function(done) {
+      helpers.stubUtxos(server, wallet, 1, function() {
+        var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', 0.99995, null, TestData.copayers[0].privKey_1H_0);
+        server.createTx(txOpts, function(err, tx) {
+          should.exist(err);
+          err.code.should.equal('INSUFFICIENTFUNDS');
+          var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', 0.99995, null, TestData.copayers[0].privKey_1H_0, 5000);
+          server.createTx(txOpts, function(err, tx) {
+            should.not.exist(err);
+            tx.fee.should.equal(5000);
+            var signatures = helpers.clientSign(tx, TestData.copayers[0].xPrivKey);
+            // Sign it to make sure Bitcore doesn't complain about the fees
+            server.signTx({
+              txProposalId: tx.id,
+              signatures: signatures,
+            }, function(err) {
+              should.not.exist(err);
+              done();
+            });
+          });
+        });
+      });
+    });
+
     it('should fail to create tx for dust amount', function(done) {
       helpers.stubUtxos(server, wallet, [1], function() {
         var txOpts = helpers.createProposalOpts('18PzpUFkFZE8zKWUPvfykkTxmB9oMR8qP7', 0.00000001, null, TestData.copayers[0].privKey_1H_0);
@@ -1445,7 +1471,7 @@ describe('Wallet service', function() {
 
     it('should fail to create tx that would return change for dust amount', function(done) {
       helpers.stubUtxos(server, wallet, [1], function() {
-        var fee = Bitcore.Transaction.FEE_PER_KB / 1e8;
+        var fee = 10000 / 1e8;
         var change = 0.00000001;
         var amount = 1 - fee - change;