I am working on a private messasing functionality for my site,
is there a way to get push notifications from the server, that the user has received a new message?
the only technique I know is to constantly poll the server via ajax to see if there are new messages, and reload the messenger window if needed.
thanks for any feedback!
UPD: so far the following directions have been identified:
1) Comet
2) BOSH - Bidirectional-streams Over Synchronous HTTP
3) XMPP - this is what google talk is based on
You might want to look into XMPP and BOSH. Very comet like and ejabberd combined with nginx can maintain 1000's of connections on a very small box.
Take a look at one of my projects www.vooices.us to see what we have done with XMPP and BOSH.
http://www.ejabberd.im/
http://github.com/ssoper/jquery-bosh/tree/master JQueryBosh - to enable quick and easy access to XMPP over HTTP
It is relativly easy to set up and install.
Paul.
There isn't any way for the server to push information to the client, but you could always use Comet. Yes, you'd be polling the server, but not constantly. You'd keep each connection open for about 30 seconds (that's the interval I've always seen used) and then open a new connection when needed.
EDIT: Adobe Flash allows persistent connections to the server, so you could use that. See this article for details.
Sounds like the Comet probably links to some useful stuff (Look into Google's GTalk):
http://alex.dojotoolkit.org/2006/02/what-else-is-burried-down-in-the-depths-of-googles-amazing-javascript/
There are a lot of good libraries that help you to do this
XMPP - BOSH is a good combination which I use on my websites
XMPP servers
Ejabberd, Openfire I use ejabberd
You can use Strophe along with Ejabberd to capture notifications in javascript. If you want to send notifications from code
There are libraries like JAXL and XMPPHP that let you do this, but this is in PHP.
Related
I have some subscribers that they are listening to "mytopic"...I send message to them by browser UI just like attached image
but now I want to do this work in code environment
what should I do and whats that code and methods?
-----> attached image
Thanks
You should have mentioned what programming language you want to use. Every language may offer a different API and specification.
In case of using Java, you can simply program according to the JMS specification
https://docs.oracle.com/javaee/7/api/javax/jms/package-summary.html
Also, the Apache ActiveMQ installation comes with a few examples that you can use as a reference. E.g. see
examples/openwire/swissarmy/src/TopicPublisher.java
You should have a look at ActiveMQ Protocols - for example you can use the ActiveMQ REST API to POST messages to the topic or use JMS.
Then you can look at how to use these from a "client" (presumably your central server) perspective.
For REST from Java (say) you could look at this article
I have a Web Server implemented using dot net MVC4. There are clients connected to this web server which perform some operations and upload live logs to the server using WebClient.UploadString method. Sending these logs from client to server is being done in group of 2500 characters at a time.
Things work fine until 2-3 client upload logs. However when more than 3 clients try to upload logs simultaneously they start receiving "http 500 internal server error".
I might have to scale up and add more slaves but that will make the situation worse.
I want to implement Jenkins like live logging, where logs from slave are updated live.
Please suggest some better and scalable solution to this problem.
Have you considered looking into SignalR?
It can be used for anything from instant messaging to stocks! I have implemented both a chatbox, and a custom system that sends off messages, does calculations and then passes them back down to client. It is very reliable, there are some nice tutorials, and I think it's awesome.
I am sure that this is answered dozens of times, but I am at a loss as to what keywords to search for and thus I hope that someone can at least tell me where I should be looking given an explanation of my scenario.
I need two services (one can be just a client if that is easier) to talk to each other, but the client will be on a private network whereas the server will be on the internet. I want to be able to push jobs to the client, but the server obviously does not have an IP to hit the client. I'd rather not poll from the client every X seconds. I have read various topics all circling this issue and so I am going to throw out a few terms that I think are relevant, but I am not sure which to use or exactly how.
Comet, SignalR, WebSockets, XSockets, Publisher/Subscriber Pattern...
I have looked at each of these and I am not sure which is the right way to go. The client can certainly "subscribe" to the server on startup, so that should not be an issue. But the client should be either a console app, windows service, or WCF service. It seems Comet and SignalR are more for ASP.NET apps, where the client is JS in a browser. I just need "server(client)" to server connection where the client is behind firewalls.
Which of these terms (or none of them) is a good way to handle server -> client push notifications?
Pub/Sub architecture pattern with something like Azure Service Bus should help you create the solution you desire. This does require that service and the client are aware of the bus. For the plumbing of the client and the services use the WCF which has built in bindings to facilitate the use of this pattern.
Azure: How to Use Service Bus Topics/Subscriptions.
Azure SB has a counter part that works on-premises as well. There are other popular message bus tech (NServiceBus, MasTransit, etc.)
You can have a look at node.js together with socket.io.
This will give everything you need.
socket.io uses web sockets, and if the browser does not support web sockets, it gracefully falls back to other communication mechanism like xhr, flash, polling, aso.
I am building a project which requires constant connection with the server.
There are two major ways to achieve this:
Ajax pull
Ajax push
I have to decide between pinging a server (expensive) and maintaining keep-alive connections (firewalls block that.)
I was thinking about the live video streams. They are not keep-alive connections, nor frequent pings.
Is it possible, to send data, like JSON strings through rtmp?
It would be theoretically possible to implement RTMP's AMF3 and AMF0 Message types to carry the data. RTMP [Wikipedia]
The problem is that using a protocol typically used for streaming video might get your connection blocked or throttled by some service providers that limit such protocols to conserve bandwidth (and prevent employees from watching internet videos at work).
Maybe this article may be of some use to you. It explains how to set up an RTMP server with nginx.
From the article:
nginx is an extremely lightweight web server, but someone wrote a RTMP module for it, so it can host RTMP streams too. However, to add the RTMP module, we have to compile nginx from source rather than use the apt package. Don't worry, it's really easy. Just follow these instructions. :)
One comment on this article by a user named 'stefaniuk' linked to a github respitory for this that I think you should look in to. Check it out here.
I want to communicate xml serialized objects from the server to the client and the other way arround. Now it is (probably) easy to invoke methods from a mobile client (compact framework) using WCF, but is there a way so that the server can invoke methods on the client side or some other way to pull data from the client? I know that callback contracts are not available in the compact framework as you can see here: http://blogs.msdn.com/andrewarnottms/archive/2007/09/13/calling-wcf-services-from-netcf-3-5-using-compact-wcf-and-netcfsvcutil-exe.aspx
Originally I thought of socket programming and of developing this by myself, then someone here mentioned WCF. But it seems like WCF only would work in a non mobile environment as I need callbacks.
Anyone can help me with this? Is it possible to develop a two way communication with a desktop server and multiple mobile clients using WCF, or will I have to do socket programming?
Thanks for any advice or any kind of help!
at ctacke
Thank you for your help. I actually stumbled across your Padran web server before.Havent really checked it out yet. But I definitely will do that later on. Anyway, a socket solution does not seem that bad at the moment. In the meanwhile I figured that it is quite easy to send data from multiple clients to a 'socket server'. If I can manage those connections somehow I can send data back to the clients. And then I would have to come up with some kind if protocol which handles the data or commands I send over the network... I guess the hardest part would be to make up such a protocol as I do not have a clue about that atm...
Even if you go to sockets it might be a bit difficult due to routing, carrier filtering and NAT translations (you've not mentioned what your actual network topology is). This is the reason that most mobile applications have to poll the server, even if it is a "push" paradigm (like Exchange's push mechanism, where the client actually polls).
Generally speaking, unless you're on something like a local wireless network where you have solid, routable, unfiltered network access, the client should periodically call the server and ask if the server has data. If it does, then it pulls the data from the server.
EDIT
Now that we know a little more about your topolgy from your comment, I can steer you a little more. Unfortunately Microsoft has not made it easy for Windwos CE devices to host services (WCF or otherwise). There is, in theory, the required infrstructure to build up your own WCF channel and actually host a service, but it's not a trivial task. I looked into it quite some time ago and figured it was a couple months of work and that would have been with the assistance of someone in Redmond that knew how the existing Exchange channel works.
Personally I'd opt for hosting a REST-based web service using our Padarn web server because it's simple to do and I've done it for quite a number of clients now. I realize that it's a little self-serving to propose Padarn as a solution but the entire reason I implemented custom IHttpHandlers in Padarn was because I couldn't find anything else out there that really provided any easy way for a CE device to host it's own services and it's a problem we often have to provide a solution for.
The other options would be things like a proprietary socket solution, hosting an FTP server on the device, using the (abhorrent, IMO) MS-provided HTTP server with ISAPI, Telnet or something along those lines. All of them seem either a hack, a lot of work or both.