From 03cccc2f8f1a03aadf639da168798ba08c1610dd Mon Sep 17 00:00:00 2001
From: Christian Pointner <equinox@spreadspace.org>
Date: Sun, 7 May 2017 21:55:39 +0200
Subject: use reader/writer interface for fowarder

---
 src/hub/src/spreadspace.org/sfive/s5srvForward.go | 75 ++++++++++++++---------
 1 file changed, 45 insertions(+), 30 deletions(-)

diff --git a/src/hub/src/spreadspace.org/sfive/s5srvForward.go b/src/hub/src/spreadspace.org/sfive/s5srvForward.go
index e88a79d..a479c2e 100644
--- a/src/hub/src/spreadspace.org/sfive/s5srvForward.go
+++ b/src/hub/src/spreadspace.org/sfive/s5srvForward.go
@@ -33,25 +33,24 @@
 package sfive
 
 import (
-	"bytes"
 	"encoding/json"
+	"errors"
+	"io"
 	"net/http"
 	"time"
 )
 
 func findMaxId(values []DataUpdateFull) int {
 	maxId := -1
-	for i := range values {
-		id := values[i].SourceHubDataUpdateId
-		if id > maxId {
+	for _, value := range values {
+		if id := value.SourceHubDataUpdateId; id > maxId {
 			maxId = id
 		}
 	}
 	return maxId
 }
 
-func (srv Server) forwardGetLastUpdate(baseurl string, client *http.Client) (lastId int, hubUuid string, err error) {
-	hubUuid = srv.GetHubUuid()
+func fwdGetLastUpdate(baseurl string, client *http.Client, hubUuid string) (lastId int, err error) {
 	lastId = -1
 
 	var resp *http.Response
@@ -78,11 +77,30 @@ func (srv Server) forwardGetLastUpdate(baseurl string, client *http.Client) (las
 	return
 }
 
+func fwdPostUpdates(client *http.Client, url string, pr *io.PipeReader) (int, error) {
+	resp, err := client.Post(url, "application/json", pr)
+	if err != nil {
+		return 0, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return 0, errors.New("")
+	}
+	dec := json.NewDecoder(resp.Body)
+	result := WebUpdatesPostResponse{}
+	if err = dec.Decode(&result); err != nil {
+		return 0, err
+	}
+	return result.NumUpdates, nil
+}
+
 func (srv Server) forwardRun(baseurl string, client *http.Client) {
 	url := baseurl + "/updates/_bulk"
+	hubUuid := srv.GetHubUuid()
 tryResync:
 	for {
-		lastId, _, err := srv.forwardGetLastUpdate(baseurl, client)
+		lastId, err := fwdGetLastUpdate(baseurl, client, hubUuid)
 		if err != nil {
 			s5l.Printf("fwd: lastupdate returned err: %v", err)
 			time.Sleep(5 * time.Second)
@@ -95,7 +113,7 @@ tryResync:
 		for {
 			updates, err := srv.GetUpdatesAfter(lastId, 5000)
 			if err != nil {
-				s5l.Printf("fwd: failed reading updates: %v\n", err)
+				s5l.Printf("fwd: failed reading updates: %v", err)
 				time.Sleep(500 * time.Millisecond)
 				continue nextBatch
 			}
@@ -107,34 +125,31 @@ tryResync:
 				continue nextBatch
 			}
 
-			// TODO: directly write to client body
-			buf := &bytes.Buffer{}
-			enc, err := NewStatefulEncoder(buf)
-			if err != nil {
-				s5l.Printf("fwd: failed encoding init message: %v\n", err)
-				time.Sleep(500 * time.Millisecond)
-				continue nextBatch
-			}
-			for _, upd := range updates {
-				if err := enc.Encode(upd); err != nil {
-					s5l.Printf("fwd: failed encoding updates: %v\n", err)
-					time.Sleep(500 * time.Millisecond)
-					continue nextBatch
+			pr, pw := io.Pipe()
+			go func(pw *io.PipeWriter) {
+				defer pw.Close()
+
+				enc, err := NewStatefulEncoder(pw)
+				if err != nil {
+					s5l.Printf("fwd: failed encoding/sending init message: %v", err)
+					return
 				}
-			}
+				for _, upd := range updates {
+					if err := enc.Encode(upd); err != nil {
+						s5l.Printf("fwd: failed encoding/sending updates: %v", err)
+						return
+					}
+				}
+			}(pw)
 
-			resp, err := client.Post(url, "application/json", buf)
-			if err != nil {
-				s5l.Printf("fwd: post failed: %v\n", err)
+			if num, err := fwdPostUpdates(client, url, pr); err != nil {
+				s5l.Printf("fwd: failed sending updates: %v", err)
 				continue tryResync
-			}
-			resp.Body.Close()
-			if resp.StatusCode != http.StatusOK {
-				s5l.Printf("fwd: post failed: %s\n", resp.Status)
+			} else if num != len(updates) {
+				s5l.Printf("fwd: server acknowledged wrong number of updates: expected %d, got: %d", len(updates), num)
 				continue tryResync
 			}
 
-			s5l.Printf("fwd: post OK")
 			lastId = findMaxId(updates)
 			s5l.Printf("fwd: new lastid: %d", lastId)
 		}
-- 
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