From fa40917053211bc2a2d60509028e83b029801475 Mon Sep 17 00:00:00 2001
From: Mark Liversedge <liversedge@gmail.com>
Date: Tue, 8 Sep 2015 11:48:46 +0100
Subject: [PATCH] API Buffered Write

.. when sending metrics, since if no selection is made
   it can result in thousands of needless updates !
---
 httpserver/httpresponse.cpp | 21 +++++++++++++++++++++
 httpserver/httpresponse.h   |  7 +++++++
 src/APIWebService.cpp       | 20 ++++++++++----------
 src/RideDB.y                | 13 ++++++-------
 4 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/httpserver/httpresponse.cpp b/httpserver/httpresponse.cpp
index 542177011..597b65899 100644
--- a/httpserver/httpresponse.cpp
+++ b/httpserver/httpresponse.cpp
@@ -11,6 +11,8 @@ HttpResponse::HttpResponse(QTcpSocket* socket) {
     statusText="OK";
     sentHeaders=false;
     sentLastPart=false;
+    buffersize=4096;
+    barry.reserve(4096);
 }
 
 void HttpResponse::setHeader(QByteArray name, QByteArray value) {
@@ -72,6 +74,25 @@ bool HttpResponse::writeToSocket(QByteArray data) {
     return true;
 }
 
+void HttpResponse::bwrite(QByteArray data)
+{
+    if (barry.size() && (barry.size() + data.size() > buffersize)) {
+        // flush buffer
+        write(barry);
+        barry = data;
+    } else {
+        barry.append(data);
+    }
+}
+
+void HttpResponse::flush()
+{
+    if (barry.size()) {
+        write(barry, true);
+        barry.clear();
+    }
+}
+
 void HttpResponse::write(QByteArray data, bool lastPart) {
     Q_ASSERT(sentLastPart==false);
     if (sentHeaders==false) {
diff --git a/httpserver/httpresponse.h b/httpserver/httpresponse.h
index 8c47af4d3..ccf0dcc31 100644
--- a/httpserver/httpresponse.h
+++ b/httpserver/httpresponse.h
@@ -85,6 +85,11 @@ public:
     */
     void write(QByteArray data, bool lastPart=false);
 
+    // buffered write
+    void setBuffersize(int size) { buffersize=size; barry.reserve(size); }
+    void bwrite(QByteArray data);
+    void flush();
+
     /**
       Indicates wheter the body has been sent completely. Used by the connection
       handler to terminate the body automatically when necessary.
@@ -136,6 +141,8 @@ private:
     */
     void writeHeaders();
 
+    int buffersize;
+    QByteArray barry;
 };
 
 #endif // HTTPRESPONSE_H
diff --git a/src/APIWebService.cpp b/src/APIWebService.cpp
index fa241dd60..9aa3daf74 100644
--- a/src/APIWebService.cpp
+++ b/src/APIWebService.cpp
@@ -116,28 +116,28 @@ APIWebService::writeRideLine(QList<int> wanted, RideItem &item, HttpRequest *req
     if (item.dateTime.date() < since) return;
 
     // date, time, filename
-    response->write(item.dateTime.date().toString("yyyy/MM/dd").toLocal8Bit());
-    response->write(",");
-    response->write(item.dateTime.time().toString("hh:mm:ss").toLocal8Bit());;
-    response->write(",");
-    response->write(item.fileName.toLocal8Bit());
+    response->bwrite(item.dateTime.date().toString("yyyy/MM/dd").toLocal8Bit());
+    response->bwrite(",");
+    response->bwrite(item.dateTime.time().toString("hh:mm:ss").toLocal8Bit());;
+    response->bwrite(",");
+    response->bwrite(item.fileName.toLocal8Bit());
 
     if (wanted.count()) {
         // specific metrics
         foreach(int index, wanted) {
             double value = item.metrics()[index];
-            response->write(",");
-            response->write(QString("%1").arg(value, 'f').simplified().toLocal8Bit());
+            response->bwrite(",");
+            response->bwrite(QString("%1").arg(value, 'f').simplified().toLocal8Bit());
         }
     } else {
 
         // all metrics...
         foreach(double value, item.metrics()) {
-            response->write(",");
-            response->write(QString("%1").arg(value, 'f').simplified().toLocal8Bit());
+            response->bwrite(",");
+            response->bwrite(QString("%1").arg(value, 'f').simplified().toLocal8Bit());
         }
     }
-    response->write("\n");
+    response->bwrite("\n");
 }
 
 void
diff --git a/src/RideDB.y b/src/RideDB.y
index 239ff4add..4460542f3 100644
--- a/src/RideDB.y
+++ b/src/RideDB.y
@@ -494,7 +494,7 @@ APIWebService::listRides(QString athlete, HttpRequest &request, HttpResponse &re
     if (metrics != "") wantedNames = metrics.split(",");
 
     // write headings
-    response.write("date, time, filename");
+    response.bwrite("date, time, filename");
 
     int i=0;
     foreach(const RideMetric *m, indexed) {
@@ -506,16 +506,16 @@ APIWebService::listRides(QString athlete, HttpRequest &request, HttpResponse &re
         if (wantedNames.count() && !wantedNames.contains(underscored)) continue;
 
         if (m->name().startsWith("BikeScore"))
-            response.write(", BikeScore");
+            response.bwrite(", BikeScore");
         else {
-            response.write(", ");
-            response.write(underscored.toLocal8Bit());
+            response.bwrite(", ");
+            response.bwrite(underscored.toLocal8Bit());
         }
 
         // index of wanted metrics
         wanted << (i-1);
     }
-    response.write("\n");
+    response.bwrite("\n");
 
     // parse the rideDB and write a line for each entry
     QString ridedb = QString("%1/%2/cache/rideDB.json").arg(home.absolutePath()).arg(athlete);
@@ -562,8 +562,7 @@ APIWebService::listRides(QString athlete, HttpRequest &request, HttpResponse &re
 
         // regardless of errors we're done !
         delete jc;
-
-        return;
     }
+    response.flush();
 }
 #endif