I'm new to XMPP and the xmpp4r library, so please forgive my noob question if this is obviously documented somewhere.
What's the most straightforward way, in a synchronous manner, to find out if a given JID is online? (so that I can call something like is_online?(jid) in an if statement)
My details:
I'm writing a Sinatra app that will attempt to send a message to a user when a particular url gets requested on the web server, but it should only try to send the message to the user if that user is currently online. Figuring out if a given JID is online is my problem.
Now, I know that if I connect and wait a few seconds for all the initial presence probe responses to come back to the Roster helper, then I can inspect any of those presences from my Roster and call #online? on them to get the correct value. But, I don't know when all of the presence updates have been sent, so there's a race condition there and sometimes calling #online? on a presence from my roster will return false if I just haven't received that presence probe response yet.
So, my current thinking is that the most straightforward way to find out if someone is online is to construct a new Presence message of type :probe and send that out to the JID that I'm interested in. Here's how I'm doing it right now:
#jabber is the result of Client::new
#email is the jid I'm interested in polling
def is_online?(jabber, email)
online = false
p = Presence.new
p.set_to(email)
p.set_from(jabber.jid)
p.set_type(:probe)
pres = jabber.send(p) do |returned_presence|
online = returned_presence.nil?
end
return online
end
Now, this works in cases where the user is actually online, but when the user is offline, it looks like the presence probe message that comes back is being caught by some other presence_callback handler that doesn't know what to do with it, and my is_online? function never finishes returning a value.
Can anyone help me by providing a simple example is_online? function that I can call, or point me in the right direction for how I can detect when the roster is done getting all the initial presence updates before I try checking a presence for #online?
As it turns out, there's not a synchronous way to ask for a JID presence. You've just got to ask for what you want, then wait for your response handler to fire when the response arrives.
Related
I'm basically following the tutorial on https://www.sinch.com/docs/video/javascript/#groupcalling.
I'm able to get things working, however I am unable to end the call. Right now I have 2 browser tabs pretending to be different users joining the same group chat. "onGroupLocalMediaAdded" and "onGroupRemoteCallAdded" do get called, and I can display things fine. But I can't figure out how a user can leave the group chat and ultimately trigger a call to "onGroupRemoteCallRemoved"
The Call class has a "hangup" method, but GroupCall does not.
any ideas?
Use call conference, it will be with a media server, callgroup will try to set up media to each client and will most likely impact your callquality.
http://download.sinch.com.s3.amazonaws.com/docs/javascript/latest/reference/classes/CallClient.html#method_callConference
I think I figured it out. Group Calling is really peer to peer calling. So hanging up means iterating through each call object you received from a peer and calling hangup.
My terminate connection function now contains:
this.remoteCallsMap.forEach( (call) => {
call.hangup();
});
I'm going to play around with call conference as mentioned in the other responses, but figured I'd post the answer in case anyone else plays around with call group and can't figure out how to end the call.
I'm looking to develop a chat application with Pubnub where I want to make sure all the chat messages that are send is been stored in the database and also want to send messages in chat.
I found out that I can use the Parse with pubnub to provide storage options, But I'm not sure how to setup those two in a way where the messages and images send in the chat are been stored in the database.
Anyone have done this before with pubnub and parse? Are there any other easy options available to use with pubnub instead of using parse?
Sutha,
What you are seeking is not a trivial solution unless you are talking about a limited number of end users. So I wouldn't say there are no "easy" solutions, but there are solutions.
The reason is your server would need to listen (subscribe) to every chat channel that is active and store the messages being sent into your database. Imagine your app scaling to 1 million users (doesn't even need to get that big, but that number should help you realize how this can get tricky to scale where several server instances are listening to channels in a non-overlapping manner or with overlap but using a server queue implementation and de-duping messages).
That said, yes, there are PubNub customers that have implemented such a solution - Parse not being the key to making this happen, by the way.
You have three basic options for implementing this:
Implement a solution that will allow many instances of your server to subscribe to all of the channels as they become active and store the messages as they come in. There are a lot of details to making this happen so if you are not up to this then this is not likely where you want to go.
There is a way to monitor all channels that become active or inactive with PubNub Presence webhooks (enable Presence on your keys). You would use this to keep a list of all channels that your server would use to pull history (enable Storage & Playback on your keys) from in an on-demand (not completely realtime) fashion.
For every channel that goes active or inactive, your server will receive these events via the REST call (and endpoint that you implement on your server - your Parse server in this case):
channel active: record "start chat" timetoken in your Parse db
channel inactive: record "end chat" timetoken in your Parse db
the inactive event is the kickoff for a process that uses start/end timetokens that you recorded for that channel to get history from for channel from PubNub: pubnub.history({channel: channelName, start:startTT, end:endTT})
you will need to iterate on this history call until you receive < 100 messages (100 is the max number of messages you can retrieve at a time)
as you retrieve these messages you will save them to your Parse db
New Presence Webhooks have been added:
We now have webhooks for all presence events: join, leave, timeout, state-change.
Finally, you could just save each message to Parse db on success of every pubnub.publish call. I am not a Parse expert and barely know all of its capabilities but I believe they have some sort or store local then sync to cloud db option (like StackMob when that was a product), but even if not, you will save msg to Parse cloud db directly.
The code would look something like this (not complete, likely errors, figure it out or ask PubNub support for details) in your JavaScript client (on the browser).
var pubnub = PUBNUB({
publish_key : your_pub_key,
subscribe_key : your_sub_key
});
var msg = ... // get the message form your UI text box or whatever
pubnub.publish({
// this is some variable you set up when you enter a chat room
channel: chat_channel,
message: msg
callback: function(event){
// DISCLAIMER: code pulled from [Parse example][4]
// but there are some object creation details
// left out here and msg object is not
// fully fleshed out in this sample code
var ChatMessage = Parse.Object.extend("ChatMessage");
var chatMsg = new ChatMessage();
chatMsg.set("message", msg);
chatMsg.set("user", uuid);
chatMsg.set("channel", chat_channel);
chatMsg.set("timetoken", event[2]);
// this ChatMessage object can be
// whatever you want it to be
chatMsg.save();
}
error: function (error) {
// Handle error here, like retry until success, for example
console.log(JSON.stringify(error));
}
});
You might even just store the entire set of publishes (on both ends of the conversation) based on time interval, number of publishes or size of total data but be careful because either user could exit the chat and the browser without notice and you will fail to save. So the per publish save is probably best practice if a bit noisy.
I hope you find one of these techniques as a means to get started in the right direction. There are details left out so I expect you will have follow up questions.
Just some other links that might be helpful:
http://blog.parse.com/learn/building-a-killer-webrtc-video-chat-app-using-pubnub-parse/
http://www.pubnub.com/blog/realtime-collaboration-sync-parse-api-pubnub/
https://www.pubnub.com/knowledge-base/discussion/293/how-do-i-publish-a-message-from-parse
And we have a PubNub Parse SDK, too. :)
I've created a real time game for Google Play Game Services. It's in the later alpha stages right now. I have a question about sendReliableMessage. I've noticed certain cases where the other peer doesn't receive the message. I am aware that there is a callback onRealTimeMessageSent and I have some code in my MainActivity:
#Override
public void onRealTimeMessageSent(int i, int i2, String s) {
if(i== GamesStatusCodes.STATUS_OK)
{
}
else
{
lastMessageStatus=i;
sendToast("lastMessageStatus:"+Integer.toString(lastMessageStatus));
}
}
My games render loop is checking every iteration the value of lastMessageStatus and if there was something other than STATUS_OK I'm painting a T-Rex right now.
My question is is checking the sent status really enough? I also could create source code where the sender has to wait for an Acknowledged message. Each message would be stamped with a UUID and if ack is not received within a timeout then the sender would send the message again? Is an ACK based system necessary to create a persistent connection?
I've noticed certain cases where there is some lag before the opposite peer received the reliable message and I was wondering is there a timeout on the sendReliable message? Google Play Services documentation doesn't seem to indicate in the documentation that there is a timeout at all.
Thank you
Reliable messages are just that, reliable. There are not a lot of use cases for the onRealTimeMessageSent callback for reliable messages because, as you said, it does not guarantee that the recipient has processed the message yet. Only that it was sent.
It may seem annoying, but an ACK-based system is the best way to know for sure that your user has received the message. A UUID is one good way to do this. I have done this myself and found it to work great (although now you have round-trip latency).
As far as timeout, that is not implemented in the RealTime Messaging API. I have personally found round trip latency (send message, receive ACK in callback) to be about 200ms, and I have never found a way to make a message fail to deliver eventually even when purposefully using bad network conditions.
I'm working on a YRS 2013 project and would like to use Twilio. I already have a Twilio account set up with over $100 worth of funds on it. I am working on a project which uses an external API and finds events near a location and date. The project is written in Ruby using Sinatra (which is going to be deployed to Heroku).
I am wondering whether you guys could guide me on how to approach this scenario: a user texts to the number of my Twilio account (the message would contain the location and date data), we process the body of that sms, and send back the results to the number that asked for them. I'm not sure where to start; for example if Twilio would handle some of that task or I would just use Twilio's API and do checking for smss and returning the results. I thinking about not using a database.
Could you guide me on how to approach this task?
I need to present the project on Friday; so I'm on a tight deadline! Thanks for our help.
They have some great documentation on how to do most of this.
When you receive a text you should parse it into the format you need
Put it into your existing project and when it returns the event or events in the area you need to check how long the string is due to a constraint that twilio has of restricting messages to 160 characters or less.
Ensure that you split the message elegantly and not in the middle of an event. If you were returned "Boston Celtics Game", "The Nut Cracker Play". you want to make sure that if both events cannot be put in one message that the first message says "Boston Celtics Game, Another text coming in 1 second" Or something similar.
In order to receive a text message from a mobile device, you'll have to expose an endpoint that is reachable by Twilio. Here is an example
class ReceiveTextController < ActionController
def index
# let's pretend that we've mapped this action to
# http://localhost:3000/sms in the routes.rb file
message_body = params["Body"]
from_number = params["From"]
SMSLogger.log_text_message from_number, message_body
end
end
In this example, the index action receives a POST from Twilio. It grabs the message body, and the phone number of the sender and logs it. Retrieving the information from the Twilio POST is as simple as looking at the params hash
{
"AccountSid"=>"asdf876a87f87a6sdf876876asd8f76a8sdf595asdD",
"Body"=> body,
"ToZip"=>"94949",
"FromState"=>"MI",
"ToCity"=>"NOVATO",
"SmsSid"=>"asd8676585a78sd5f548a64sd4f64a467sg4g858",
"ToState"=>"CA",
"To"=>"5555992673",
"ToCountry"=>"US",
"FromCountry"=>"US",
"SmsMessageSid"=>"hjk87h9j8k79hj8k7h97j7k9hj8k7",
"ApiVersion"=>"2008-08-01",
"FromCity"=>"GRAND RAPIDS",
"SmsStatus"=>"received",
"From"=>"5555992673",
"FromZip"=>"49507"
}
Source
What is the proper xmpp4r way to know if a given contact is online before sending them a message?
Can you post sample xmpp4r code for doing this?
Here is my use case:
If contact online, send :normal message
Else, email contact
Here are things I have working code for:
Send messages of various types
Get a roster/contact list
Register a call back to detect changes in presence
However, I can't find a place that directly addresses a work flow like this:
Loop through each JID in your roster
If jid.is_online? == true, send IM
Else, send email
I've read that you should send a JID a message of type :headline and if that fails, you know the user is offline. In my tests, if the user is ONLINE, they'll receive a message of type headline. This is suboptimal, as users should only receive messages to read, not noise to determine online status.
I've read that on sign on, all of your contacts will bounce a presence status back at you, and that status is the sole indication that they are online - assuming that there isn't a disconnect or presence change you've yet to receive. So you should register a presence call back, record the initial users who ping you back, and then add or remove from the list based on your running roster presence callback.
If this is truly the way to do it:
Can I get some example code of how to collect all the "I'm here" presence confirmations on sign on via xmpp4r?
Why, oh why, was xmpp designed this way and why is this better than offering an "is_online_and_available" method?
So the answer here is adding a message call back and checking inside the block for the type:
m = Message.new(to, body)
cl.send(m)
cl.add_message_callback do |m|
if m.type == :error
puts "type: #{m.type}"
else
puts "not an error"
end
end
This requires threading as you have to be listening for the response.