I am looking for a simple and reliable Comet javascript library. I want to keep a persistent streaming of data from my server (via PHP script) to the client side. I tried building my own using the iframe technique, but there are lots of issues with safari which I experienced. I am just hoping someone else has created a simple library for it?
There is a jquery comet plugin
Probably the best version though is the Dojo library
I have a quick list of commands I used to get a jetty server with comet up and running here
It's not just the javascript library that you need, but a server-side implementation as well. Depending on your needs, you'll need to pick a proper implementation.
You mentioned PHP, which is typically difficult with long-held requests. Other options include having a separate server for your comet requests, or using a SaaS solution, such as WebSync OnDemand.
Depending on which option you pick for the server, you will have one or more javascript clients available. But you need to determine your server implementation first, then use the appropriate javascript implementation to match.
Have a look at http://www.ape-project.org/ Pretty quick setup process.
have you tried JSON-RPC. Apparently Dojo has good support for it, though I haven't tried it thoroughly
JSON-RPC
Dojo Documentation
Related
First off, I am not asking for any code or anything like that.
all I need is some advise.
I'm creating a roulette game and everything in my roulette game is based on jQuery.
however, as we all know, jQuery is client side so I was thinking about using AJAX to send some details back to server and from the server to the users browser so I can make this roulette game work in "multiplayer" fashion... But the issue is that I don't think its possible to send the roulette's wheel animation to the server and back to users browser so I am a bit confused about this!
In my research I came across some information (old ones) about using node.js and jquery together! I don't know if this is possible or how easy it would be to use my jquery code in node.js as I have never used node.js before..
so the question that i have is:
based on the information i provided above and my requirements, what are my options?
can I use AJAX to achieve what i am trying to do and if so, a bit
information would be great.
if AJAX is out of question, is it possible to use my jquery code in
node.js to achieve what I am trying to do?
ANY ADVISE WOULD BE APPRECIATED.
P.S. I don't want to use HTML5 as 1st I don't know much about HTML5 and also, some devices, browsers do not support it.
Thanks
The best way is to use websockets to ensure real time communication. One of the best alternatives for implementing that could be using a server under node.js. Have a look to this video from Code School node.js tutorials: https://www.youtube.com/watch?v=mtDK4jf4RS0 where is ilustrated how to implement a real time chat. Your problem is based on the same.
There are three parts to a multiplayer game displayed in a browser:
client-side display,
server-side data management,
client-server communication.
If you're already set on your display technology (jQuery), then you're probably going to use $.ajax() for client-server communication. However, technologies used for server-side data management are completely up to you and they don't necessarily have any connection to the technologies used for display and communication (meaning the traditional communication initiated by client).
Basically, use any kind of server technology stack you like. Node.js might do just fine but there are many other viable alternatives. They just need to support communication with the client.
So, to be absolutely clear, your question doesn't really make sense. You might use jQuery in the client and Node.js on the server, but they will never really "work together". They will manage completely separate parts of your application and connect through protocols not specific to either of them.
As for the animation, the animation itself is solely a client-side problem. If you want to "synchronize the animation" across multiple clients, you can let the clients communicate with the server, but they only ever need to send/receive plain data. Then you adjust the client-side animation based on the received data.
As another poster points out, websockets are a better fit for this than regular client-initiated HTTP requests. Not because of "the animation", but because you want all the clients to receive the information about the start of betting at the same time.
I am also developing a MMO game using javascript only. Firstly, there are two different types of javascript here. Usual client side javascript (the one you already know) and the server side javascript (i.e. Node.js).
You will need to develop both client and server before connecting them with jQuery's Ajax. So you need to study Node.js before designing overall architecture of your game.
I read many Node.js tutorials and watched many youtube tutorial videos but I was still confused, before I really sat down and read a good textbook that explained from basics, one like below. Try to get hold of it from your local library.
Express web application development learn how to develop web applications with the Express framework from scratch by Hage Yaapa
Express is the popular framework that runs on Node.js now. So it's worth getting familiar with Express Framework. Once you understand how express app works (not so difficult), you will see how you can frame your game structure like I did :)
In order for many clients to share same animation, there must a server that synchronizes the game state. Ajax can only link between server-client communication in my understanding. There is no mechanism that connects between clients. The clients ask server what number was the result of roulette roll and show the corresponding animations.
Yes, you can use NodeJS and jQuery together.
NodeJS is server-side, meaning that you set up a server (a lot of people use the Express module, which is easy to use), which serves content to clients asking for it. Your server-side code can be in any language supporting sockets, not just NodeJS. But NodeJS is easy to use if you know JS already.
jQuery is client-side, meaning that it's executed by the user's browser, and may or may not have a server-side component (if it doesn't need it), or it might have one where it sends requests to the server-side code. When it requests a page from the server, it can be static content (like when you request index.html) or dynamic via an AJAX request. Client-side browser code must be HTML/CSS/JS (you can't make Firefox or Chrome interpret C, for example).
I was using Greasemonkey eariler in the week to automate some calls to a page to scrape some data from a website, this was awkward for two reasons:
It's GUI based instead of commandline based)
I had to store all persisted information in JSON, and not directly in a database.
Would it be possible, to use node.js as a Greasemonkey alternative since node.js can store records directly in a database, and won't be required visually load pages the way the Greasemonkey does?
Also I would think that node.js would be easier to work with since you don't have to re-deploy it's scripts to Firefox the way that you have to with GreaseMonkey, allowing you to easily use version control on separate scripting projects.
On the other hand using node.js to do GreaseMonkey's job might just be using a hammer to pound in a screw, so I thought I would check here to find out if I am mistaken.
On the other hand using node.js to do GreaseMonkey's job might just be using a hammer to pound in a screw
I would say that the opposite is true; I believe you're using Greasemonkey to do the job of a server-side processing library. Greasemonkey runs in the browser and is designed to modify your web experience by running scripts on the pages you visit.
Indeed, I believe Node.js would be very well suited to this task. With libraries like jsdom and node-jquery, you can easily do JavaScript parsing over the DOM. You may also wish to take a look at node.io, a "distributed data scraping and processing framework." Finally, you may look into non-Node (but still JavaScript) based tools, such as PhantomJS and CasperJS, which can do scraping, DOM manipulation, screenshots, and more.
The question is a bit of a non sequitur.
Greasemonkey is for clients to tweak their individual browsing experience, client-side.
Node.js is for developers to deliver applications to the masses (hopefully), server-side.
For scraping data, in an automatable way, use Node.js or some server-side library (Python works well).
For "Mashups" of webpages that you browse, use Greasemonkey.
I looking at using Javascript server side and took a look at persevere/pintura but for a novice like me, I need more documentation and tutorials and CouchDB seems to have a lot of that but is it used as a server side js tool?
Kind Regards
Yes (seconding what #Pointy said above). The JavaScript in CouchDB does run server-side. :)
Beyond that, though, JavaScript in CouchDB can do far more than just map/reduce queries. It's also used for document validation, update handling (for processing XML POSTed to CouchDB for example), as well as HTML or other markup output from either a single JSON document (using _show) or from the results of a map/reduce query (using _list).
CouchDB does not, however, offer filesystem access or TCP/IP listeners as Node.js does. Right now, the JavaScript is focused on the "shipping and handling" for the database contents (things like validation, formatting, and querying).
If you're interested in looking into options for handling things that CouchDB doesn't do "internally" (image processing, sending e-mails, etc), you might checkout my reply about CouchApp architecture options.
CouchApp's are definitely a viable option for web apps. Coupling those with replication, it's hard to beat.
http://nodejs.org/ is a great example for server-side javascript. If you don't want to write your complete webapp on NodeJS you can trigger it via the node command.
CouchDB is a database with an interresting feature, it allows you to interact via a RestFull api making it ideally suited to access over the web, either in javascript or other client environments. If you are looking for a server-side javascript development environment, try Servoy. It allows full featured server-side application development in javascript including easy database access to all major databases.
Short Answer: Yes.
Longer Answer:
There is a Javascript Engine shipped with CouchDB, which is SpiderMonkey
(the very first engine, open source, written by Brendan Eich, creator of javascript)
CouchDB's View function is JavaScript function running server side that acts as the Map half of a map/reduce operation to construct view.
Then there is client side javascript API, which can be used to communicate with the REST layer to fetch/update documents, which is also where jQuery is used by CouchDB.
More on CouchDB's both server-side & client side javascript capability:
The default engine is capable of doing many features, while package availability is limited compared to Node.js. Kan.so can be considered "NPM for CouchDB, where some packages are server side.
For example, there are frameworks like duality that try to make use of both server side & client side javascript capability to reuse code for rendering with couchDB.
More on the engine:
(The selection of spider Monkey over v8 is because for couchDB's use case the map reduce is not v8 designed for. Also include packaging, multi-threading and also historical reason v8 did not exist that time when spiderMoney is chosen) see [the mailing list] and tweet2
There is even project to port the whole CouchDB to Node.js (i.e. instead of Erlang), Chesterfield
I am glad if someone can add how Erlang talk with the javscript engine.
Thanks for everyone's answer, this is an important thing to make clear for people like me messing up couchDB with some Node.js packages
No, CouchDB is a document-oriented database that can be queried and indexed in a MapReduce fashion using JavaScript. CouchDB also offers incremental replication with bi-directional conflict detection and resolution.
http://couchdb.apache.org/
CommonJS can be used for server side JavaScript, see here: http://www.commonjs.org/
NodeJS is another: http://nodejs.org/
So just a quick intro, I am starting to explore Vaadin, and it's absolutely perfect. Previously, I was juggling PHP, Perl, Ruby, and Jquery for designing rich client web application. It didn't work out too well, as I've burnt out from trying to fix cross browser issues (aka get-it-to-work-on-IE-damn-it), handling server-side, client-side, and building a robust communication between the two tier had lot of code not related to application logic....by the time I was burnt out, only tiny bit of application logic was implemented.
Vaadin seems like the answer to my problem as it only requires Java and built on top of GWT.
However, I am curious how I can incorporate Cross-Domain Javascripting ? Back in LAMP environment, I had a CGI proxy script that loaded external URL, and injected JS into the proxy-loaded page. I used the CGI proxy script, as it rendered Javascript of the external URL well. Is there a class or package for Java or a specific Java web framework similiar to Vaadin that makes this possible ?
Thank you.
If you want to avoid any kind of proxies, and thereby keep a full context on each 'side', then you should choose easyXDM. To see it in action try http://easyxdm.net/current/example/methods.html
This fully supports all browsers, and has a neat RPC interface that lets you call methods and pass data between the domains.
If you plan to support IE6/7 then you should also try the upcoming version.
Even though the current version is fast (when used with a dependency), this one is even faster - actually nearly as fast as postMessage in never browsers!
You can easily implement the functionality yourself.
a proxy for cross domain javascript is really straightfoward.
It's just creating a request equivalent to the ajax request you want and direct it to the other domain.
ExtJS has what they call a "ScriptTagProxy" which may or may not be of use to you...
Here's a few more links about this:
http://xant.us/ext-ux/examples/css-proxy/
http://www.extjs.com/forum/showthread.php?17691-Cross-domain-Ext.Ajax-Ext.data.Connection
I have read up about what COMET streaming is, and all the various hacks required to get it working across the major browsers. The problems encountered seem to be two fold: 1. Server being able to support many persistent connections 2. Implementing the JS functionality
I have an application where I need to perform COMET streaming. I have already tackled the first problem above - I have a custom server running which delivers updates as it arrives in chunks. I want to now be able to connect using JS to this URL, so I can receive the updates.
Is there a simple COMET library I can use for this? I saw the Orbited project. Can I use the client side JS of orbited to perform this? What kind of modifications do I need to perform in the backend for this?
If you can get your server code to conform to the Bayeux specification then you can use any of the existing cometd javascript implementations, current available in DOJO and jQuery. Unfortunately, the spec is quite complex, especially if you want to do both long-polling and callback-polling. You may be better of just running an existing cometd server like Jetty and then writing a client library for your server code to push data to it.