Develop Reference

Dead connection message and delivery receipt received delay in stream management - MongooseIM server 2.0.0

I have enable stream management in both side client or server. I have two users A and B. Both users are online.Then user A suddenly lose his connection. but A user still appear online on user B and as well as on server. During that time user B sending message on user A. Those message are not lost but when user A is appear online again it will receive those message after 2-3 minute.and i will get message stanza on Offline storage and delivery receipt i will got on SM storage.This issue same occur on one to one chat and mucLight. have i need to customized any mongooseIM modules. Please guide me why users received delay message when their are lost his connection. is it possible to changed SM storage to offline storage(MAM). here's link for same issue i have found same issue on this link (https://www.ejabberd.im/faq/tcp) but have not lost my messages but just received it delay.
I am use smack-4.2 lib on my Android app.and following code used to enabled stream management in XMPPTCPConnection.
static{
XMPPTCPConnection.setUseStreamManagementDefault(true);
XMPPTCPConnection.setUseStreamManagementResumptionDefault(true);
}
Here's my ejabbered.cfg file for mod_stream_management module
{mod_stream_management, [
% default 100
% size of a buffer of unacked messages
% {buffer_max, 100}
% default 1 - server sends the ack request after each stanza
% {ack_freq, 1}
% default: 600 seconds
% {resume_timeout, 600}
]},
I have also enable following module on my config file
%% Only archives for c2c messages, good performance.
{mod_mam_odbc_user, [pm]},
{mod_mam_cache_user, [pm]},
% {mod_mam_mnesia_dirty_prefs, [pm]},
% {mod_mam_odbc_arch, [pm, no_writer]},
{mod_mam_odbc_async_pool_writer, [pm]},
{mod_mam, []}
I found little solution here smack connect to xmpp server with previous stream id but its not work on mongooseIM-2.0 server.
Thank you in advanced.

I'm assuming below that user A, when they reconnect, is not using Stream Resumption (as defined by XEP-0198: Stream Management) and merely starting a new session.
This means that on the server side there's still a dangling process waiting for Stream Resumption to happen. When user A is already reconnected to the server, the dangling process times out (which takes resume_timeout seconds) and sends the messages it had stored for delivery in the outgoing message buffer.
If you don't like this behaviour, you can do one of these:
a) (not advised) disable Stream Management and send a Message Archive Management query (that is use mod_mam) to have the most up to date conversation state each time you establish a new connection to the server
b) leave Stream Management enabled, but use Stream Resumption if only possible; that is, you always try to resume the previous session, unless you don't have the previous session ID or the server rejects the resumption request; ideally you would also use Message Archive Management
c) use Delayed Delivery aka mod_offline, but risk that in some rare cases, if you use multiple devices, the messages might be sent to a wrong device; for example, if you have a phone and a laptop, it might happen that your messages will reach the laptop, but never reach the phone

Did you try using mod_ping and configure on ejabbered.cfg file.
{mod_ping, [{send_pings, true}]},
fore more details please follow this link mod_ping

Reconnection Error Stream Management Smack

i discovered a really big problem (probably mine?) about the XMPP reconnection process in smack library v4.1.5 (Android) and openfire v4.0.1.
I activated the stream management on the client in this way:
XMPPTCPConnection.setUseStreamManagementDefault(true);
XMPPTCPConnection.setUseStreamManagementResumptionDefault(true);
and activated the automatic reconnection in this way:
ReconnectionManager.getInstanceFor(this.xmppConnection).enableAutomaticReconnection();
After the first successfull connection and login, when the internet connection goes down and the reconnection process starts I get the following error:
W/AbstractXMPPConnection: Connection closed with error
org.jivesoftware.smack.XMPPException$StreamErrorException: conflict You can read more about the meaning of this stream error at http://xmpp.org/rfcs/rfc6120.html#streams-error-conditions
<stream:error><conflict xmlns='urn:ietf:params:xml:ns:xmpp-streams'/></stream:error>
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:1003)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$300(XMPPTCPConnection.java:944)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnection.java:959)
The reconnection manager connects and authenticates very well but then I receive the previous error!
I tried to change the resource also but nothing, it doesn't work!
Someone could help me in understanding what is wrong?

Android MQTT , Client presence How to know setWill is working?

I am using below code to connect to MQTT server
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(true);
options.setKeepAliveInterval(Constants.CLOUD_KEEP_CONN_ALIVE);
byte[] payload = String.valueOf(0).getBytes((Charset.defaultCharset());
options.setWill("willTopic", payload, 0, true);
mAndroidAsyncClient.connect(options, this);
Once connected I get a callback . Now my question is how to debug in server , that setWill is working using mosquitto_sub .
I am using setWill to know client presence.
To confirm setWil is working I wanted to debug from server by subscribing to willtopic and get logs .
I tried connecting and disconnecting many times but there is message sent over will topic.
Command I used on server is
mosquitto_sub -t appTopic --will-topic willTopic
It will be helpful if anyone share the command or way to debug Mqtt setWill.
I tried referring to How to Find Connected MQTT Client Details . But it did not workout for me.

The only real way to test that the LWT (Last Will & Testement) message gets sent is to make the broker send it.
To do this you will have to cause a none clean shutdown of the client, given this is on android the easiest way would be to run the app in the emulator, let it connect then kill the emulator (You have to do this because last time I tried to get the emulator to disable all network activity I discovered it just sent the Network Down broadcasts but left the network up). Once the keep alive period expires and the broker notices the client has gone it should publish the LWT message and you should be able to see this with mosquitto_sub.
There may be ways to query the broker for a given LWT message but this would be totally dependant on the broker you are using. I'm not aware of any brokers that make this easy, but there may be something under the '$SYS/#' topic tree on brokers that support that interface.
EDIT:
Also when using mosquitto_sub you should just be using the -t not --will-topic. --will-topic is the topic that mosquitto_sub would publish it's own LWT on if it was disconnected. You can have as many -t options as you need, and -v will print the topic name before the message body so you can tell them apart
mosquitto_sub -v -t appTopic -t willTopic

Pubnub+Python SDK on an Ubuntu Azure-hosted machine. Connection problems

I am experiencing a bad behavior of Pubnub in the following scenario:
Pubnub SDK for Python as a subscriber
Python 3+Django on Ubuntu 14.04
Ubuntu machine hosted on Azure
Android Pubnub client as a publisher
It seems to be that, at a certain point, the Pubnub connection on the server side becomes stale, that is, any message sent from the client is not received by the subscriber.
I have noticed that there are some errors on the log related to pubnub connection:
WARNING 2015-09-30 17:21:24,778 connectionpool 26551 139638563919616 Retrying (Retry(total=0, connect=None, read=None, redirect=None)) after connection broken by 'ReadTimeoutError("HTTPConnectionPool(host='pubsub.pubnub.com', port=80): Read timed out. (read timeout=320)",)': /subscribe/.../.../0/...?uuid=...&auth=...&pnsdk=PubNub-Python/3.7.3
After about 5 minutes, the message is received and correctly processed.
I guess that the root of the problem lays in the way Azure manages long http connections, as:
The problem does not arise on my local machine, which has the very same OS version and the same stack
There is an obscure 'azure' parameter in the Python SDK. I tried to activate it without any noticeable difference
As a test I added two more subscribers on my pc and they both receive messages instaneously
Thanks.

It seems to be that the root cause is the fact that Azure cuts HTTP connections above 4 minutes (https://azure.microsoft.com/it-it/blog/new-configurable-idle-timeout-for-azure-load-balancer/).
On the other hand, though, Pubnub creates connections with 5 minutes timeout (320 seconds, see https://github.com/pubnub/python/blob/master/pubnub.py#L1881).
Unfortunately, the Pubnub 320 seconds timeout can not be changed, whereas the Azure timeout seems to be modifiable only via Powershell scripts (uncomfortable, especially if you do not have a Microsoft Window machine).
All in all, I changed the Pubnub source code with a 120 seconds timeout and now everything is going pretty well.
It would be advisable to:
Document that on Pubnub side
Modify Pubnub so that the 320 seconds timeout can be changed
Improve the Azure interface in order to change the timeout parameter without using Powershell

If there is anything that can be done from the PubNub SDK, look at this:
Azure flag on init
https://github.com/pubnub/python/blob/master/pubnub.py#L2112
https://github.com/pubnub/python/blob/master/pubnub.py#L2141-L2146
Linux platform
And this should be getting called if Azure is running on linux:
- https://github.com/pubnub/python/blob/master/pubnub.py#L69-L77
Let me know if that helps any.

Can't launch server QWsServer error : The address is protected

I'm trying to do a C++ websocket server. I want to "speak" to an android Application and send it videos.
I'm using QtWebsocket from this repository
To test, I copied the code from Example/Server.
I haven't had any compilation error but the server cannot start:
Error: Can't launch server QWsServer error : The address is protected
I am beginner in network and websockets.

The port you are trying to listen on -> 80 is available only to privileged applications (and only if no other process is listening on it). Try using different port (ex. 8080), or running your application as root.
For more info about ports check out: Privileged Ports