I was asked to establish a connection using the cometD library going from ios7 to a server. After some research I came to the conclusion that my two options were Dave Duncan's DDComet, and Paul Crawford's FayeObjC. I tried using DDComet, but when I opened the github project, it came with 30+ errors. They were mainly ARC errors witch I attempted to fix, but it only ended up crashing the application. I then took a look at the FayeObjC documentation, and quickly realized that it had very little/nothing to do with cometD.
My question is: Is CometD an outdated library? If so, what should I be using as a replacement. If not, how would I be able to implement it in ios7?
CometD is not an outdated library. The last version of CometD is barely one month old.
The CometD project does not have an ObjC client.
I know of companies that have written one and maintain themselves that is fully compatible with CometD 2.x and 3.x.
It may happen that in future their implementation is open sourced.
Faye uses the Bayeux protocol, defined by the CometD project, so in theory they should be able to interoperate. However, I don't know exactly the status of either Faye or FayeObjC.
As the CometD project leader I'd love to have an ObjC client in the project, but it has not happened yet.
Related
does anyone know how to use the new APNS provider API from Apple that was introduced in a Session of the WWDC2015? For my tests I used PushMeBaby(a OpenSource Push server from github). But this little App won't work anymore in the future. has someone implemented a HTTP2 client in Swift yet?
Unfortunately, Apple has still not released any information regarding the new APNS HTTP/2 service, or even anything regarding when information will become available.
Most developers seem to be eager to make the switch to the new endpoints, but we will all have to wait for the time being.
I'm now using this Code from Github.
For me it's actually easier to use the APNSNetwork Class directly, so i don't have to mess up with Carthage.
The Class is very easy to use and available for Swift2 and Swift3.
I hope this will help you in your Project ;-)
Best regards,
Michael
I have run into trouble with Socket.io regarding memory leaks and scaling issues lately. My decision to use Socket.io was made over a year ago when it was undoubtedly the best library to use.
Now that Socket.io causes much trouble, I spent time looking for alternatives that became available in the meantime and think that both Engine.io and SockJS are generally well suited for me. However, in my opinion both have some disadvantages and I am not sure which one to choose.
Engine.io is basically the perfect lightweight version of Socket.io that does not contain all the features I do not require anyway. I have already written my own reconnection and heartbeat logic for Socket.io, because I was not satisfied with the default logics and I never intended to use rooms or other features that Socket.io offers.
But - in my opinion - the major disadvantage of Engine.io is the way connections are established. Clients start with slower jsonp-polling and are upgraded if they support better transports. The fact that the clients which support websockets natively (number increasing steadily) have a disadvantage in the form of a longer and unstable connection procedure over those clients which use outdated browsers, contradicts my sense of how it should be handled.
SockJS on the other hand handles the connections exactly as I would like to. From what I have read it seems to be pretty stable while Engine.io has some issues at this time.
My app is running behind an Nginx router on a single domain, therefore I do not need the cross-domain functionality SockJS offers. Because of providing this functionality, however, SockJS does not expose the cookie data of the client at all. So far I had a 2-factor authorization with Socket.io via cookie AND query string token and this would not be possible with SockJS (with Engine.io it would).
I have read pretty much all what is avilable about and pros and cons of both, but it seems there is not much being discussed or published so far, espacially about Engine.io (there are only 8 questions tagged with engine.io here).
Which of the 2 libraries do you prefer and for which reason? Do you use them in production?
Which one will likely be maintained more actively and could have a major advantage over the other in the future?
Have you looked at Primus? It offers the cookie requirements you mention, it supports all of the major 'real-time'/websocket libraries available and is a pretty active project. To me it also sounds like vendor lock-in could be a concern for you and Primus would address that.
The fact that it uses a plugin system should also a) make it easier for you to extend if needed and b) may actually have a community plugin that already does what you need.
Which of the 2 libraries do you prefer and for which reason? Do you use them in production?
I have only used SockJS via the Vert.x API and it was for an internal project that I would consider 'production', but not a production facing consumer app. That said, it performed very well.
Which one will likely be maintained more actively and could have a major advantage over the other in the future?
Just looking over the commit history of Engine.io and SockJS, and the fact that Auttomatic is supporting Engine.io makes me inclined to think that it will be more stable, for a longer period of time, but of course that's debatable. Looking at the issues for Engine.io and SockJS is another good place to evaluate, but since they're both split over multiple repos it should be taken with a grain of salt. I'm not sure where/how Automattic is using Engine/Socket.io, but if it's in WordPress.com or one of their plugins, it has substantial production-at-scale battle testing.
edit: change answer to reflect cookie support confirmed by Primus author in comments below
I'd like to redirect you to this (quite detailed) discussion thread about SockJS and Engine.io
https://groups.google.com/forum/#!topic/sockjs/WSIdcY14ciI
Basically,
SockJS detects working transports before marking the connection
as open. Engine.io will immediately open the connection and upgrade
it later.
flash, one of the Engine.io fallbacks
(and not present in SockJS) loads slowly and in environments
behind proxies takes 3 seconds to timeout.
SockJS doesn't use flash and therefore doesn't need to work around
this issue.
SockJS does the upgrade on start. After that you have
a consistent experience. You send what you send, you receive
what you receive.
Also, as far as I can tell, engine.io-client (the client-side) library for engine.io, does not support requirejs builds, so that's another negative point. (SockJS does build perfectly).
You may also consider node-walve. Complete WebSocket basic. Extremely performant as fully stream based.
Example of how to use:
walve.createServer(function(wsocket) {
wsocket.on('incoming', function(incoming) {
incoming.pipe(process.stdout, { end: false });
});
}).listen(server);
It may not be the best choice if you feel not secure in the nodejs environment (e.g. extending prototypes for API sugar), contributing to the project (though the code is more readable as socket.io).
My first post.
I have experience of basic java servlet and jsp and have got my webpage implemented in tomcat7.
Regarding Websocket, I am finding difficult to build understanding of how to implement it, i want to use tomcat8 implementation of websocket api and uplift my webpage (jsp, java, jquery, tomcat7) to use the websocket features, have not been able to find the the tutorial that can guide me through, something like hello world example. any pointers (sample codes, tutorials)?
have tried to understand tomcat8 examples but not understanding them at all
You need to understand that you don't just "add" WebSocket to an existing web application.. to make it faster, better, cheaper, more scalable, etc. Instead, you have to completely re-architect the web-layer of the application to take advantage of its capabilities.
I suggest that you first read a lot about WebSocket and what the whole idea is before you try to write any code, using Tomcat or any other WebSocket-capable server.
Nick Williams has a forthcoming book that appears to cover everything in the web application world, and as I understand it, will have a great deal of information about WebSocket-based code. You will unfortunately have to wait until March 2013 (at least) to use that particular book.
I'm sure there are similar books available, or even online tutorials to help get you started using WebSocket. Just be aware that switching to WebSocket isn't some simple configuration option: it's a very disruptive change to any existing web application.
Well, I have doubts about this technology, more precisely in its implementation, can not find good examples on the Internet, as it involves javascript and php, only, you would have some links where I can find this stuff really works and that ?
A great source for all things Comet is Comet Daily. Unfortunately it's not updated all that often any more but there are some fantastic old articles in there. It's contributed to by guys that have been developing Comet solutions for over 10 years.
Comet seems to get incorrectly bundled as meaning just one particular connection mechanism is used, but it's actually a paradigm for realtime push from server to client. Comet servers can use HTTP Streaming, HTTP Long-Polling, classic polling and WebSockets.
If you are interested in the latest Push Technology then you should take a look at WebSockets which is a standardised approach to not only server to client push, but also bi-directional realtime communication between servers and clients (web browsers and other clients).
Some current trending push technologies are:
socket.io
Hosted WebSockets services such as Pusher - who I work for
Faye for self hosted Ruby or Node dev
SignalR for IIS and .NET
There are many more and more information on realtime web technologies can be found on this guide.
If you want to use PHP you could struggle to build an application using realtime Push which will scale above a small number of connections. Have a read through this question on concurrency - How to implement event listening in PHP for more information.
Do you specifically mean Ajax push? Because a more common method is comet push, I has been a while I worked with this, probably more browsers support this.
A good implementation can be found here:
http://www.ape-project.org/
Well it's called Ajax Push engine, so I suppose that is what you are looking for.
If you work with Java/Scala/Ruby/Groovy, take a look at Atmosphere, which is being actively developed/used (I'm the creator). There are many samples available.
Check out the Bayeux Protocol and CometD implementation in Java & Javascript.
From http://cometd.org/ :
CometD is a scalable HTTP-based event routing bus that uses a Ajax Push technology pattern known as Comet.
Here the link to an interesting article describing the technologies involved and a comparison of CometD and Atmosphere implementations.
I'm relatively new to the whole AJAX way of doing things so please excuse me if I'll mix two different things (although I'd appreciate it greatly if you could comment me on that).
My question is this:
I have many web clients (lets say around 1500) whom I want when starting up to "subscribe" to the web server with some sort of Id and then I want the web server (APACHE) to send them a relevant url (build dynamically doesn't really matter for this purpose) to display (sort of redirect).
Now my problem is basically that I've spent the last few days reading a lot of articles and howto's on how this should be done and I think I have too many buzz-words.
I think that in order to solve my problem I need some sort of implementation of COMET with something called "continuations" (to support that many clients). Is that correct?
Am I going down the right path?
Does GWT have any connection with this?
Thank you all very much in advance
EDIT: After reading some more I think that basically the Java Servlet 3.0 Asynchronous support is exactly what I need on the server side (correct me if I'm wrong) and I'm still debating on the client side? Maybe GWT after all?
Thanks
OK, so I indeed was making a bit of a mess earlier and I'm putting it out there so my nonsense doesn't confuse anyone.
What I was looking for was asynchronous request support both on the server side, regarding the thread handling to allow many users and scalability, and on the client side for ease of use of the Comet patter.
I've found that Jetty, Tomcat and Grizzly all offer a solution for this (just search the specific server with Comet and see what they offer) but I've decided to use the Servlets 3.0 spec as supported in Glassfish even though it will only be released with Java EE 6 as to not be tied down to a specific server.
On the client side I will probably go with GWT for many other reasons not related to Comet and because it has sufficient support for Comet.
Thanks
You may want to try StreamHub Push Server and the accompanying GWT Comet Adapter. This will give you a scalable Comet server and a GWT Client-side.