From 880f98e66914ede724593fb86572698f0319eafc Mon Sep 17 00:00:00 2001
From: Chris Kleeschulte <chrisk@bitpay.com>
Date: Tue, 17 Oct 2017 17:46:11 -0400
Subject: [PATCH] Fixed pagination for getAddressHistory.

---
 lib/services/address/index.js | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/lib/services/address/index.js b/lib/services/address/index.js
index 57883317..c628a529 100644
--- a/lib/services/address/index.js
+++ b/lib/services/address/index.js
@@ -32,6 +32,7 @@ var AddressService = function(options) {
     this._network = 'testnet';
   }
 
+
 };
 
 inherits(AddressService, BaseService);
@@ -71,11 +72,12 @@ AddressService.prototype.getAddressHistory = function(addresses, options, callba
       return callback(err);
     }
 
-    txList = utils.dedupByTxid(txList);
+    // TODO: these should already be ordered correctly, please check
+   txList = utils.dedupByTxid(txList);
     txList = utils.orderByConfirmations(txList);
 
     var results = {
-      totalCount: txList.length,
+      totalCount: options.txCount,
       items: txList
     };
 
@@ -110,7 +112,6 @@ AddressService.prototype.getAddressSummary = function(address, options, callback
     unconfirmedBalanceSat: 0,
     unconfirmedTxApperances: 0,
     txApperances: 0,
-    transactions: []
   };
 
   self.getAddressHistory(address, options, function(err, results) {
@@ -174,6 +175,9 @@ AddressService.prototype._getAddressSummaryResult = function(txs, address, resul
     }
 
     if (!options.noTxList) {
+      if (!result.transactions)  {
+        result.transactions = [];
+      }
       result.transactions.push(tx.txid());
     }
 
@@ -338,7 +342,8 @@ AddressService.prototype._getTxidStream = function(address, options) {
 
   var criteria = {
     gte: start,
-    lte: end
+    lte: end,
+    reverse: true // txids stream from low confirmations to high confirmations
   };
 
   // txid stream
@@ -357,6 +362,13 @@ AddressService.prototype._transformTxForAddressHistory = function(opts, chunk, e
 
   var txid = _.isString(chunk) ? chunk : self._encoding.decodeAddressIndexKey(chunk).txid;
 
+  opts.txCount++;
+
+  // no need to look up the tx if the tx is outside the range of the query.
+  if (opts.txCount >= (opts.to + 1) || opts.txCount < (opts.from + 1)) {
+    return callback();
+  }
+
   self._tx.getTransaction(txid, opts, function(err, tx) {
 
     if (err) {
@@ -407,6 +419,7 @@ AddressService.prototype._getAddressHistory = function(address, options, callbac
   options.endHeightBuf = new Buffer(4);
   options.endHeightBuf.writeUInt32BE(options.end);
   options.results = [];
+  options.txCount = 0; // this tracks the number of txs in the record set for pagination
 
   if (_.isUndefined(options.queryMempool)) {
     options.queryMempool = true;
@@ -430,19 +443,26 @@ AddressService.prototype._getAddressHistory = function(address, options, callbac
       if (mempoolTxs.length <= 0) {
         return next();
       }
-      async.mapSeries(mempoolTxs, function(tx, next) {
+      async.mapLimit(mempoolTxs, 4, function(tx, next) {
         self._transaction.setTxMetaInfo(tx, options, next);
       }, function(err, txs) {
         if (err) {
           return next(err);
         }
-        options.results = txs;
+        // what tx range are we looking for?
+        options.results = txs.slice(options.from, options.to);
         next();
       });
     },
     // stream the rest of the confirmed txids out of the address index
     function(next) {
 
+      if (options.results.length >= (options.to - options.from)) {
+        return callback(null, options.results);
+      }
+
+      options.from += options.results.length;
+
       var txStream = self._getTxStream(address, options);
 
       txStream.on('end', function() {
@@ -453,6 +473,7 @@ AddressService.prototype._getAddressHistory = function(address, options, callbac
         log.error('Address Service: txstream err: ' + err);
         txStream.unpipe();
       });
+
       var txidStream = self._getTxidStream(address, options);
       txidStream.pipe(txStream);
     }