I'm developing WebSocket messaging backend using Spring WebSockets, which uses SockJS + STOMP protocol. The reason why not to use plain WebSockets is because I will need to leverage security integration that SockJS provides in Spring WebSockets and also other neat features from SockJS, such as rooms, subscriptions, etc. I was wondering if this is a good option to use so that mobile (iOS and Android) and Web client apps can easily connect to the backend server and perform messaging. If yes, then what libraries I can use for iOS and Android.
On SockJS GitHub page they are also listing available client libraries, but no iOS nor Android. So, I'm wondering if SockJS is even worth to use just because of that.
I found that for iOS client Primus-Objc (GitHub page) library claiming that they can connect to native WebSockets, Socket.IO, SockJS or perhaps engine.io. is that a true statement? And event if that's true, what about the quality of that library?
And event if it is ok to use SockJS on the back, then would it be also possible to show an example code for iOS and Android so that I can perform a proof of concept on mobile devices?
If SockJS is not a good option for me, then would it be better than to build my messaging app with Socket.io + Node.js (using JavaScript). Socket.io seems to me have all needed client libraries for iOS (official library by Socket.IO guys) and Android (official library by Socket.IO guys).
Another option can be to use Netty-Socket.io library and build each endpoint manually without any help from Spring Framework (which I'm considering to use) but there is small challenge that I'll have to tackle, that is security. Somebody actually already tried to do it (the same author asking question on the official Netty-Socket.IO Github page) but looks like he didn't have a luck in solving it yet.
Maybe it's more than a year since the question was asked. But, because it's getting in the first results when Googling for SockJS+Android. So, I am posting my answer.
From my experience with a recent project I worked on, we were able to use a STOMP client - like the one here- to connect to Spring Websocket backend from native Android app.
And from the browser, you can still use SockJS client to gain across browsers compatibility to websockets with fallback.
A note to mention that when using only STOMP client to connect to native websocket the URL will be something like ws://mydomain/SockJSEndpoint/websocket,
and when using SockJS client from the browser the URL will be like http://mydomain/SockJSEndpoint.
Please find below useful references related to your requirement for both iOS and Android
http://www.elabs.se/blog/66-using-websockets-in-native-ios-and-android-apps
https://www.cometchat.com/blog/ios-android-chat-mobile-sdk/
https://github.com/elabs/mobile-websocket-example
We have tested them, both Android-client (link) was given by #Amr K. Ismail and
this iOS-client (link) are suitable with Spring-SockJS-Server which has STOMP.
SockJS may be interesting because it provides non-ws transports. Just using WebSockets may not be possible in all situations.
There is one cross-platform SockJs client of the OpenFL project:
https://github.com/jeremyfa/openfl-sockjs
Not tested how well it works, but at least for Android it's using JavaScript from inside WebView, so should be no different than JavaScript one. Again, it is not clear how tightly it is coupled with OpenFL, but the approach of using WebView and stock SockJS client could probably be re-used.
Related
I recently started developing my first web application with Spring and I'm stuck with a question I could not really find an answer to. What I have is a simple Spring MVC application running in tomcat which provides data in form of JSON, XML or binary via REST. This service is consumed by two clients I developed, a simple Java desktop application and an Android app. So far the clients only got information about new data by polling.
What I want now, is a way for the server to send notifications/messages to the clients when new data is available. For the Android client it would be good if the notifications could received anytime, not only when the app is currently open of course. I found lots of information for JavaScript client code but very little really useful, up-to date input about what the options for java and android clients are.
It would be really great if someone could give me some idea what would be the best way to achieve what I want (ideally something which integrates well with Spring on the server side), what protocols/libraries/frameworks to use, maybe even point me to some example or tutorial, how to implement this on server and client side.
Thanks in advance for any input.
For android or mobile devices, Google Cloud Messaging is the preferred way of sending messages to applications running on devices.
Example : spring gcm server side project and a sample tutorial.
For desktop apps, either poll regularly the server or run something in background like crontab or active-mq to check the messages and start the desktop app.
WebSockets are the best solution. check the implementation in java in the server side
I want to develop a Java server that is able to send messages asynchronously to a client in form of a website with JavaScript. I know that one possibility is using WebSockets, but these are not supported in IE 9.
For transmitting messages from client to server I can use AJAX calls with maybe a RESTful Interface on the server side.
Does anyone have a solution for this?
This is not how webservers work, most of the time. HTTP Webservers are inherently a request-response architecture:
HTTP functions as a request-response protocol in the client-server computing model. A web browser, for example, may be the client and an application running on a computer hosting a web site may be the server. The client submits an HTTP request message to the server. The server, which provides resources such as HTML files and other content, or performs other functions on behalf of the client, returns a response message to the client.
That said, there are technologies that you can use to do this. Read here about Comet and Reverse AJAX:
Is there some way to PUSH data from web server to browser?
You better implement your Java server to act as a Websocket server when it's supported by the end user. For the users who does not support Websocket it should fall back to long-polling.
This behaviour will avoid unnecessary overheads due to long-polling communications whenever possible.
The good thing is you don't have to implement all these behavious from the scratch. You can readily embed and use a reliable implementation available open source.
One such implementation is CometD project. The CometD project was available for more than a decade and it has evolved to solve most of the issues.
If you are looking for commercial products, there are many available. One such would be lightstreamer (http://www.lightstreamer.com).
You need to use a design pattern like long polling since WebSockets is not available. Rather than build it yourself you could use a library like SignalR. SignalR is an ASP.NET library but there is a client for Java (https://github.com/SignalR/java-client)
For anyone who comes across this question more recently, the modern answer (as of early 2021) supported across all browsers (except IE, which even Microsoft has given up on in favour of Chromium-powered Edge) are server-sent events. A most elegant and standardised solution to providing a pub/sub model to web clients.
I am new at using Codename One. I am trying to deploy a server that will interact with my app on Amazon Web Services using OpsWorks. The server is going to run on Apache Tomcat and be a dynamic web project written in Java, and I am wondering the best way to communicate with the Codename One client. I am planning to use the Socket classes provided by Codename One, but and not sure what to use for the server-side code. Will it work to use WebSockets from Apache? I am having difficulty debugging the server code and have hit a wall here. Thanks in advance!
WebSockets aren't compatible with sockets so you will need to code a websocket implementation which is a bit of work. I suggest you use HTTP communication which is more portable and very performant on the devices.
You can also use solutions such as PubNub which allow for fast message based communications.
I need to push events to web clients in a cross-browser manner (iPhone, iPad, Android, IE/FF/Chrome/etc.) from a Spring based Java server. I am using backbone.js on the client side.
To my best knowledge, I can either go with a Web socket only approach, or I can use something like socket.io.
What is the best practice for this issue, and which platform/frameworks should I use?
Thanks
Looks like you're interested in an AJAX Push engine. ICEPush (same group that makes ICEFaces) provides these capabilities, and works with a variety of server- and client-side frameworks. There is also APE.
You can have a look at Lightstreamer.
My company is currently using it to push real time financial data from a web server.
I suppose Grizzly or Netty may fit your needs. Don't have a real experience in that scope, unfortunately.
I'd recommend socket.io as you mentioned in your question, if you're doing browser based eventing from a remote host. Socket.io handles all the connection keep-alives and reconnections directly from javascript and has facilities for channeling messages to specific sessions (users). The real advantage comes from the two-way communication of WebSockets without all the boilerplate code of maintaining the connection.
You will need to do some digging for a java implementation thoughConsider running the server directly from V8.
I have Java and Flash client applications. What is the best way for the two to communicate without special Flash-specific servers such as BlazeDS or Red5? I am looking for a light client-only solution.
Well, you can make http requests from flash to any url... so if your java server has a point where it can listen to incoming requests and process XML or JSON, your flash client can just make the request to that url. BlazeDS and Red5 just aim to make it simpler by handling the translation for you making it possible to call the server-side functions transparently.
Are they running in a browser (applet and SWF), or are they standalone apps?
If they're running in a browser then you can use javascript. Both Flash and Java are can access javascript. It's fragile, but it works.
If they're running as actual applications then you can have Java open a socket connection on some port. Then Flash can connect to that and they can send XML data back and forth.
I've done both of these, so I know they both work. The javascript thing is fragile, but the socket stuff has worked great.
WebORB for Java may be of some help to you. It integrates with your J2EE code.
For more info:
http://www.themidnightcoders.com/weborb/java/
I'm sorry, I reread your question that you are only looking for a client side solution. In this case, WebORB will not help you. Sorry for the misunderstanding.
There's a Flash implementation of Caucho's Hessian web service protocol. This approach would be similar to using JSon or XML, but is more performant, since Hessian is a binary protocol. If you happen to be using Spring on your server, you can use the Spring/Hessian binding to call you Spring services directly from your Flash application with minimal work.
Merapi Bridge API
Merapi allows developers to connect Adobe AIR applications, written in Adobe Flex to Java applications running on the user's local computer.