I'm trying to implement a Cometd/Bayeux server on Android using iJetty. The Jetty implementation itself works just fine serving static pages along with servlets. I am trying to up the ante a bit and create a Bayeux application on the phone but I'm having some trouble. I can hit the page that has the dojo cometd scripts on it, but I am unable to subscribe to the channel. When I view firebug/chome developer tools, I see a series of posts/gets that last a couple of milliseconds (~14). However, when I run a cometd application on a normal machine, the posts/gets last several seconds (~14 seconds) before timing out and reopening the connection. This second scenario makes sense to me with my understanding of how continuation in HTTP works. So I'm thinking that something is not allowing those connections to hang open and prematurely returning a value and consequently closing the connection. I would post my source but I'm not sure what to post short of posting everything...(it is open source though so if you want to have a look it's at http://webtext-android.googlecode.com).
So my question is, does anybody think that there could be some underlying limitation imposed by the Android system that is preventing these servlets from working? Are there assumptions that are made by the Jetty Bayeux implementation with regards to the underlying system? Or is it more likely that somehow I have a bad implementation of the ContinuationCometdServelt? I should note that all of the posts/gets from the client return 200 OK messages so I'm not inclined to think that the Android system is simply terminating the connection.
I know this is a bit off the wall and I'm definitely trying to do something a bit out of the ordinary but any suggestions or tips would be greatly appreciated.
In case anybody discovers this and has similar problems (this applies to all cometd implementations regardless of host), I discovered that the issue was with using the Google js library. For some reason, the dojo scripts I was loading from Google (1.4) didn't have a valid implementation of cometd. I switched my dojo script to the one that was used by the jetty-1.6.23 example and it works perfectly.
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I want some way of creating a dedicated browser window for a browser (chrom-e/ium or firefox). Its content needs to be controlled by a java application (a http call to localhost or better a more direct way of communicating). These two should be bundled together in some way.
A little Background
I want to write a java desktop app but don't want to use Swing or javaFX for the UI. The UI should be written like a one page app and may be ported (at least partially) to the web. I have taken a look at the javafx WebView but would rather have a full fledged browser on my hands. It would also be nice to have a little more control over said browser to send files and read files in a more desktopish way. The only real requirement is that there has to be some java backend behind it and that is has to work offline.
Is something like this possible at all or is it just a pipe dream?
I am very almost a year late for the party, but:
There are a few (that I know) technologies that can help you:
Electron. It is basically what you want, you can use web
technologies to "forge" a desktop app, it's quite well known, I never used it but for what I have read that you can stick almost anything to it's "backend".
JavaFxWebView. There are some really nice ways to use it, you can
even use bootstrap and AngularJs, here is a example (not by me)
Yes it's possible and not all that unusual. Your app can open a default browser as described here -
https://stackoverflow.com/a/10967469/5087125
And then proceed to respond to http requests to your app.
I have tried searching for this strange issue I am facing but could not find anything on web.
Following is what I am trying to do.
Upload File from User browser to Play server running on some different environment
Following is the issue I am facing.
The chunk is getting truncated before reaching to Play server
Observations:
Chunk is created at client side properly from java script and websocket.send() is passing proper chunk to Play.
On Play server, the chunk is coming as a String event object which is truncated.
Very strange thing about this problem is This is happening only from some machines/networks, for all others it is working fine
When tried with different chunk size, it has been observed that for smaller chunks many of initial chunks gets received properly and later one fails
We have tried bypassing Firewalls and Proxies as well on some network to check what happens if there are no such restrictions, but it is still failing
Please give your inputs which can help me debug this and fix this. Any additional things you want I can provide, not pasting code as it is working on majority of machines and networks but failing on a few, so it does not seem to be a code issue
PS. This question can have many answers based on people's views, to all SO users, I just need help on what could be the thing which can go wrong, so please do not flag this as inappropriate
I have figured it out, the issue was with latest update of google chrome. I downloaded the chrome from here (Version 37) and it started working fine.
I came to know after a period of time that this issue was because of the implementation changes in chrome V38 for multiple frames for single message, initially it was getting transferred in a single frame so ultimately the implementation from your server side also need to be changed in order to handling the same.
I was using older version of Play framework which wasn't having this multiple frame handling implementation so it was breaking.
After updating Play to 2.2.3 it started working properly as they have implemented multiframe handling in that version. Some useful links below
Issue With Latest Chrome
Play Changelog
Changes for Continuation frame handling for WebSockets in Play 2.2.3
Basically i am trying to create a websocket based live chat for a few websites i work on.
the server i have up and working no bother running on the javax.websocket package on a glassfish server.
the standard HTML5 websocket interface i also have working no bother.
the problem is that about 10-20% or our users dont use an HTML5 compatible browser so i need a fallback. Do far the best option i can find seems to be running a swf as a middle man between the websocket server and HTML. The problem there being that action script doesnt support websockets as standard so im having to write my own wrapper.
So far i can connect to the server and perform a successful handshake, i can also receive messages from the server with no issues, the problem is sending messages.
I have had a look through https://www.rfc-editor.org/rfc/rfc6455#section-5.2 at the theory of the data frame for a websocket package and written an attempt at this, i have also looked through various other open source library's without any luck. What happens is whenever i send a message to the server i get a response of
RSV bit(s) incorrectly set.
and then the connection closes (as it should with the websocket protocol).
A large part of the problem i suspect is that this is the first time i have ever even looked at action script never mind attempted using it.
i was just wondering if anyone else had been having this problem/response and preferably has found a solution
in an idea world im looking for a tutorial that i could use to actually understand the creation of the frame better but i cant seem to find one :P
thanks
Matt
As it turns out it was just one of those bizarre bugs that happened for basically no reaseon, i ended up re-writing the section of code that manages the creation of websocket frames and frame fragmentation and it just worked.
ive had a few programmers look the the two examples of code including an action script developer and none of them can work out why the one snippet works and the other doesnt.
On the upside going back over the process has given me a better understanding of the protocol. If there is anyone else that has been having a similar problem feel free to get in touch and i will see if i can help you out.
I have some issues with my parts of final year projects. We are implementing a plagiarism detection framework. I'm working on internet sources detection part. Currently my internet search algorithm is completed. But I need to enhance it so that internet search delay is reduced.
My idea is like this:
First user is prompt to insert some web links as the initial knowledge feed for the system.
Then it crawl through internet and expand it's knowledge
Once the knowledge is fetch System don't need to query internet again. Can someone provide me some guidance to implement it? We are using Java. But any abstract detail will surely help me.
if the server side programming is you hand then you can manage a tabel having a boolean in database which shows whether the details were read before. every time your client connects to server, it will check the boolean first and if boolean was set false then it will mean that there is a need to send updates to client other wise no updates will be sent,
the boolean will become true every time when client downloads any data from server and will become false when ever the database is updated
I'm not quite sure that I understand what you're asking. Anyway:
if you're looking for a Java Web crawler, then you I recommend that you read this question
if you're looking for Java libraries to build a knowledge base (KB), then it really depends on (1) what kind of properties your KB should have, and (2) what kind of reasoning capabilities you expect from your KB. One option is to use the Jena framework, but this requires that you're comfortable with Semantic Web formalisms.
Good luck!
I am working on an application in Linux which will interfaces with hardware. One of the requirements is to create the GUI in Web-browser . the application will be c++ based. I m not familiar with web realted stuff so i want to know Is it possible to do such a thing (currently it's a console application take input from txt file/cmd line). gui will be simple using button and showing output messages on browser from the application. i want to know which technologies/languages are involved and how can it be done. some of the idea i read but havn't found anything concrete yet. if u have any idea about these or a better suggestion please share
run the app in background and communicate with browser ?
call library functions directly from browser ?
any other idea ?
I would start by setting up a regular HTTP server, like lighttp or Apache httpd.
You say you already have a command line program that does the actual work - As a first step, I would reuse that, and configure the web server to call your program using CGI - see forexample http://httpd.apache.org/docs/2.2/howto/cgi.html for apache
Finally, I'd pick some javascript framework like jQuery or YUI with Ajax capabilities to do requests to the server to call the CGI script from within a webpage. You could also create a form-based web application without ajax or any framework, but that would require you to stuff all kinds of logic in your program to generate HTML pages. By using Ajax, you can leave the command line application as is, and parse any responses it gives with javascript, and then use that to dynamically change the webpage in a way that would make sense to the user.
If this all works, then I would try to figure out how to package all these components. Perhaps you just want to create a simple archive with all the programs inside, or maybe you want to go as far as actually embedding the webserver in your program. Alternatively, you may want to do it the other way around and rewrite your program as an ISAPI module that you can plug into your webserver. Or if that's not integrated enough still you could write your own (partial) HTTP server. That's really up to you (I'd probably spend time and energy on searching for the leanest, meanest existing open source http serverr and use that instead)
At any rate, the prior steps won't be lost work. Most likely, developing the web page is going form a substantial part of the work, so I would probably create a quick and dirty working solution first using the age-old CGI trick, and then develop the webpage to my satisfaction. At that point you can already have an acceptable distributable solution by simply putting all programs in a single archive (of course you would have to tweak the webserver's configuration too, like changing the default port so it won't interfere with existing webservers.) Only after that I would spend time on creating a more integrated fancy solution.
I ended up using Wt though I'd update for future reference.
These are how I thought of doing this, in order of complexity for me:
Create a simple server-side-language (PHP/Python) website that can communicate with (ie launch and process the return of) your application
Modify your application to have a built-in webserver that just punched out HTML (command line parameters taken through the URL)
Modify the app to publish JSON and use javascript on a simple HTML page to pull it in.
You could write a Java applet (as you've tagged this thread) but I think you'd be wasting time. This can be quite simple if you're willing to spend 10 minutes looking up a few simple commands.
After 12 years, web browser-based GUI started to appear, WebUI is one of them.