Adding _streamAddressSummary

- Fn uses streamer to process data. Thus doesnt store the entire list of txid or tx details
- streamer fn can process the tx data as required

lib/services/address/index.js

@@ -574,6 +574,122 @@ AddressService.prototype._getAddressTxidHistory = function(address, options, cal
 
 };
 
+AddressService.prototype._streamAddressSummary = function(address, options, streamer, callback) {
+  var self = this;
+
+  options = options || {};
+  options.start = options.start || 0;
+  options.end = options.end || 0xffffffff;
+
+  options.from = options.from || 0; //TODO: check from/to options are working or not
+  options.to = options.to || 0xffffffff;
+
+  if (_.isUndefined(options.queryMempool)) {
+    options.queryMempool = true;
+  }
+
+  options.endHeightBuf = new Buffer(4);
+  options.endHeightBuf.writeUInt32BE(options.end);
+
+  if (_.isUndefined(options.queryMempool)) {
+    options.queryMempool = true;
+  }
+
+  //declare the queue to process tx data
+
+  var q = async.queue(function(task, cb) {
+
+    let {id, options} = task;
+
+    if (id.height === 0xffffffff) {
+
+      return self._mempool.getMempoolTransaction(id.txid, function(err, tx) {
+
+        if (err || !tx) {
+          return cb(err || new Error('Address Service: could not find tx: ' + id.txid));
+        }
+        self._transaction.setTxMetaInfo(tx, options, cb);
+
+      });
+
+    }
+
+    self._transaction.getDetailedTransaction(id.txid, options, cb);
+
+  }, 4);
+
+  q.pause(); //pause and wait until queue is set
+
+  function process_chunk(err, tx){
+
+    streamer(err, tx);
+
+    if(err){
+      q.kill();
+
+      return callback();
+    }
+
+  }
+
+  async.waterfall([
+
+    // query the mempool for relevant txs for this address
+    function(next) {
+
+      if (!options.queryMempool) {
+        return next(null, []);
+      }
+
+      self._mempool.getTxidsByAddress(address, 'both', next);
+    },
+
+    // add the meta data such as input values, etc.
+    function(mempoolTxids, next) {
+
+      if (mempoolTxids.length <= 0) {
+        return next();
+      }
+
+      mempoolTxids.map(id => q.push(id, process_chunk));
+      next();
+    },
+    // stream the rest of the confirmed txids out of the address index
+    function(next) {
+
+      var txIdTransformStream = new Transform({ objectMode: true });
+
+      txIdTransformStream._flush = function(cb) {
+        txIdTransformStream.emit('end');
+        cb();
+      };
+
+      txIdTransformStream.on('error', function(err) {
+        log.error('Address Service: txstream err: ' + err);
+        txIdTransformStream.unpipe();
+      });
+
+      txIdTransformStream.on('end', function() {
+        q.resume();
+      });
+
+      txIdTransformStream._transform = function(chunk, enc, cb) {
+        var txInfo = self._encoding.decodeAddressIndexKey(chunk);
+        q.push({ txid: txInfo.txid, height: txInfo.height }, process_chunk);
+        
+        cb();
+      };
+
+      var txidStream = self._getTxidStream(address, options);
+      txidStream.pipe(txIdTransformStream);
+
+      q.drain(next);
+
+    }
+  ], callback);
+
+}
+
 AddressService.prototype._removeBlock = function(block, callback) {
 
   var self = this;