From ba849f06d5c287e6d04e5cc91fe96c0a54df3199 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom.smeding@gmail.com>
Date: Sun, 28 Jun 2020 22:46:50 +0200
Subject: webclient: Protocol version negotiation

---
 TODO.txt              |  1 -
 webclient/client.html | 19 +++++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/TODO.txt b/TODO.txt
index 8e7ac3b..83b866c 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,5 +1,4 @@
 - Store message as UTF8 text, not blob
-- Protocol version negotiation
 - `_push message` and the response on `send` should give the msgid, so the client can implement replies
 - Message replies: referenced message should be msgid
 - Somehow communicate (push? poll?) to room members whether a particular user is currently _active_, not just online.
diff --git a/webclient/client.html b/webclient/client.html
index 766b035..fce719d 100644
--- a/webclient/client.html
+++ b/webclient/client.html
@@ -4,7 +4,9 @@
 <meta charset="utf-8">
 <title>tomsg webclient</title>
 <script>
-var sock=null,username=null;
+var PROTOCOL_VERSION=1;
+
+var sock=null,negotiated_version=false,username=null;
 var roomlist=[":console"];
 var currentroom=":console";
 var roomlogs=new Map([[":console",[]]]);
@@ -80,7 +82,7 @@ function formatTime(date){
 
 function net_historyCollectionCallback(id,list,count,cb, item,err){
 	if(err){
-		cb(err);
+		cb(null,err);
 	} else {
 		list.push(item);
 		if(list.length==count){
@@ -95,6 +97,7 @@ function reconnect(){
 	if(sock)sock.close();
 
 	net_callbacks={};
+	negotiated_version=false;
 
 	var url;
 	if(location.hostname!="")url="wss://"+location.hostname;
@@ -145,6 +148,16 @@ function reconnect(){
 	});
 	sock.addEventListener("open",function(){
 		updateStatus();
+		net_send("version "+PROTOCOL_VERSION,function(ok,err){
+			if(err){
+				var msg="Server version incompatible (we need protocol version "+
+							PROTOCOL_VERSION+"): "+err;
+				addRoomEntry(":console","error",[now(),msg]);
+			} else {
+				negotiated_version=true;
+				updateStatus();
+			}
+		});
 	});
 	sock.addEventListener("close",function(ev){
 		updateStatus();
@@ -196,6 +209,8 @@ function updateStatus(){
 		str="not connected";
 	} else if(sock.readyState==0){
 		str="connecting...";
+	} else if(!negotiated_version){
+		str="versioning...";
 	} else if(username){
 		str="u: "+username;
 	} else {
-- 
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