1> Just want to understand how SignalR 1.x functions in a particular scenario
Lets say we have a 10 clients connected to Hub and one of the connected clients say client-1 performs a postback so OnDisconnected is called than OnConnected is called right ?
What happens if during this phase if client-2 try's to send message to client-1 exactly between the said scenario ie (msg is sent after client-1 is disconnected and before connected again )will client-1 miss the message or there's internal mechanism which makes sure client-1 does not miss the message sent by client-2
2> Second query I have is that I'm trying to pass a querystring using following code
var chat = $.connection.myHub;
$.connection.myHub.qs = { "token": "hello" };
but not able to retrieve it on the server side from the Context object
using
Context.QueryString.AllKeys
I even tried
var chat = $.connection.myHub;
$.connection.myHub.qs = "token=hello" ;
But it does not work ie when I check the keys, token is not present in AllKeys
Will appreciate if someone just help me out.
1: If a postback occurs a client will disconnect and then connect. However, when the client performs a connect again it will have a different Connection Id than it had prior to the postback. Therefore, any message sent to the old connection id will be missed because when the users browser connects again it will be known as a different client.
2: You're trying to set the query string on the hub proxy, not the connection. What you should be doing is:
$.connection.hub.qs = { foo: "bar" };
Related
I have two available Twilio <client> to receive inbound calls on my website (after caller enters a code) using JS Quickstart and Twilio client PHP library, these calls are recorded and registered on my database.
I've noticed when one <client> hangs up an open inbound call , this call goes to the website of the other <client> I have have 2 registers on my database instead of one.
This is an example:
<?php
//...
//Validating connection status
//$estd is the connection status I get via AJAX
if($estd=="open"){
$call = $twilio->calls($callsid)->update(array("status" => "completed"));
$calla = $twilio->calls($callsid)->fetch();
$parentCall = $calla->parentCallSid; //parent call
$calld = $twilio->calls($parentCall)->update(array("status" => "completed"));
} else if($estd=="pending"){
$call = $twilio->calls($callsid)->update(array("status" => "completed"));
$calla = $twilio->calls($callsid)->fetch();
$parentCall = $calla->parentCallSid; //parent call
$calld = $twilio->calls($parentCall)->update(array("twiml" => '<Response><Dial timeout="20" record="record-from-answer" recordingStatusCallback="https://mywebsite.com/record.php" recordingStatusCallbackEvent="in-progress completed absent"><Client><Identity>the_other_client</Identity><Parameter name="numdoc" value="user_code"/></Client></Dial></Response>'));
}
?>
How can I fix it?
I'd like your help.
I believe this could be occurring because a single incoming voice call will trigger both of your $estd if statements.
According to Twilio documentation (https://www.twilio.com/docs/voice/client/javascript/connection#status), an incoming call will first have the status pending, and then the status open. If your statuscallbackURL is set for when the status changes, you may be calling your record-keeping code more than once. Depending on how you have your SQL you may be inserting new records each time.
The way to prevent the double record is to save the resource SID for the call in your database and insert on duplicate key or update to prevent creating new records.
Alternatively, if the code snippet you are displaying is from record.php, when you make your outbound call using Twiml, you use a callbackURL to call record.php -- at which time you may be creating a new record in your database (as this call will have it's own unique SID). If you want to attach it to the current record, then you will need to create a different callbackURL for those outbound dials made from this script.
(But it is difficult from the details you have provided to know what code is being called when).
I am developing messenger IOS app based on Firebase Realtime Database.
I want that all messages to be ordered based on timestamp.
There is a scenario as like below.
There are 3 clients. A, B and C.
1)
All clients register 'figure-1' listener to receive messages from others.
<figure-1>
ref.queryOrdered(byChild: "timestamp").queryStarting(atValue: startTime).observe(.childAdded, with:
{
....
// do work for the messages, print, save to storage, etc.
....
// save startTime to storage for next open.
startTime = max(timeOfSnapshot, startTime)
saveToStorage(startTime)
}
2)
Client A write message 1 to server with ServerValue.timestamp().
Client B write message 2 to server with ServerValue.timestamp().
Client C write message 3 to server with ServerValue.timestamp().
They sent messages extremely the same moment.
All clients have good speed wifi.
So, finally. Server data saved like 'figure-2'
<figure-2>
text : "Message 1", timestamp : 100000001
text : "Message 2", timestamp : 100000002
text : "Message 3", timestamp : 100000003
As my listener's code, i keep messages on storage and next listening timestamp for preventing downloading duplicated messages.
In this case.
Does Firebase always guarantee to trigger callback in order as like below?
Message 1
Message 2
Message 3
If it is not guaranteed, my strategy is absolutely wrong.
For example, some client received messages as like below.
Message 3 // the highest timestamp.
// app crash or out of storage
Message 1
Message 2
The client do not have chance to get message 1, 2 anymore.
I think if there are some nodes already, Firebase might trigger in order for those. Because, that is role of 'queryOrdered' functionality.
However, there are no node before register the listener and added new nodes additionally after then. What is will happen?
I suppose Firebase might send 3 packets to clients. (No matter how quickly the message arrives, Firebase has to send it out as soon as it arrives.)
Packet1 for message1
Packet2 for message2
Packet3 for message3
ClientA fail to receive for packet 1,2
ClientA success to receive for packet 3
Firebase re-send packet 1,2 again.
ClientA success to receive for packet 1,2
Eventually, all datas are consistent. But ordering is corrupted.
Does Firebase guarantee to occur events in order?
I have searched stack overflow and google and read official documents many times. However, i could not find the clear answer.
I have almost spent one week for this. Please give me piece of advice.
The order in which the data for a query is returns is consistent, and determined by the server. So all clients are guaranteed to get the results in the same order.
For new data that is sent to the database after the listeners are attached, all remote clients will receive it in the same order. The local client will see events for it's write operation right away though, before the data even reaches the database server.
In figure 2, it is actually quite simple: since each node has a unique timestamp, and they will be returned in the order of that timestamp. But even if they'd have the same timestamp, they'd be returned in the same order (timestamp first, then key) for each client.
The requirement in our project is, Web UI(MVC 5) will place a request to adapter(intermediate layer) which takes 3-4mins to process the request and computes response. This response needs to be pushed back to UI. We are planning to implement Signalr for posting back the response to UI. I did a small POC on SignalR to open connection and to call a method from javascript and get response back. how can I push the data from server to client(once connection is set), no call from javascript/Web for requesting the response?.
To push datas from the server to the client the basic usage is :
On the client side :
var myHub = $.connection.CustomHub;
myHub.client.myFunction= function (param) {
alert(param);
};
On the server side :
Clients.All.myFunction("parameter");
To find more infos about signalr take a look here :
http://www.asp.net/signalr/overview/getting-started/tutorial-getting-started-with-signalr
You can download the light chat project in the page it's a good start.
Get Hubcontext of the application
IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext('HubName');
On top of hubcontext can broadcast message to all the clients or groups or to specific client based on connection Id
hubContext.Clients.Client(connectionId).JavaScript function(data)
There are running examples of SignalR, but in those, i have seen that the process is started by the client i.e. every piece of code contains following similar lines
$.connection.hub.start().done(function () {
$('#mybutton').click(function () {
notifier.server.doLongOperation();
});
});
The process on server starts on $('#mybutton').click and then responds.
Is my understanding correct? If yes then is it possible to start the process by Server? I mean Server will push messages to all clients without any triggering from the client side.
This didn't work
var context = GlobalHost.ConnectionManager.GetHubContext<Broadcast>();
context.Clients.All.Send(message);
My bad, method name on client side was incorrect. Problem solved
Yes it is possible to send server initiated "messages" from the server to clients. Note that you have to call a method on the client. Note that it's a RPC/Remoting type of communication.
On the server you'd have a code like this:
Clients.All.Say("Hello World!");
where the client needs to define a function:
myHub.client.say = function (message) {
console.log(message);
});
see the SignalR documentation
I've been searching Google for awhile and there seems to be no offers on fixing this problem I have here.
I am using LuaSocket as a simple way to connect to a external server I created, and I am able to connect to it successfully and send a signal.
However, when I try to send a second message later on, the external server does not seem to be receiving the message, even though I am still connected to the socket.
socket = require("socket")
host, port = ip, port
tcp = assert(socket.tcp())
tcp:settimeout( 0 )
tcp:connect(host, port);
msg = {
["status"]="connect",
["usrName"]=username
}
msg = Json.Encode(msg)
tcp:send(msg); -- This message, the server received this message.
-- Later in my code, I attempt to send another message.
msg = {
["status"]="anotherMessage",
["usrName"]=username
};
msg = Json.Encode(msg)
tcp:send(msg); -- This message is not sending, even though i'm still connected.
You need to show what happens on the other side as it may be simply not reading even though the connection may be open. You also don't say what exactly happens when "message is not sending"; do you get an error? the script finishes but the message is not sent?
There are several things you can try:
Switch to the (default) synchronous send until you get it working; remove tcp:settimeout(0), as your send may simply fail with "timeout" message if the other side is not ready to read the message.
Check the error message from :send call to see if it's timing out or not.
local ok, err = tcp:send(msg)
Use socket.select to check if the other side it ready to accept the message you are sending.
Try adding "\r\n" at the end of your serialized JSON.