I have a project which needs live updates on certain parts of the website, this done with websockets. On other parts of the site I use POST/GET. I just came to think of it, is there any reasons not to use only websockets? What could I gain/loose by dropping POST/GET?
Browser support for Web Sockets is good in current versions. But the answer very much depends on your project.
You'll have to manage the websocket, in case it closes unexpectedly. A GET/POST is easier in that regard. You can just set an interval and if one goes missing, there's always the next request.
If it's not a critical feature, and if your audience is skewed towards chrome/firefox/safari, and your websocket implementation is solid already, i'd drop GET/POST.
Personally I think the biggest disadvantage would be browser support. Websockets have great support in Chrome and Firefox but only recently came to Internet Explorer. By completely relying on websockets unless you had a fallback you'd be cutting off some older/mobile browsers.
As kidshenlong already mentioned, the biggest problem would be browser support. You should also consider, though, that an open websocket uses up resources (mostly memory) on your server for each client that is currently connected.
Related
We have a solution that deals with devices on Windows and would like to make calls to certain components of it from webbrowsers (Edge, chrome, firefox) by using javascript so this will be done client side.
We used to do it by using activex but since this technology works pretty much only for Iexplorer and now with modern browsers being depricated, is not an option any more.
Our solution is Java based and also some C#.
Does anybody know how to do this? Thanks a lot.
Pretty much the only way to do that would be to create a web service that exposes your components, then make web requests to that service from JavaScript. That is all any modern browser will allow you to do.
We are investigating another oprtion that seems feasible, using websockets seems to be more reliable than using native messaging since the lastone relies too much on browser version and would involve the creation of an extension for at least three browsers, edge, chrome and firefox and if something changes in those browsers it would probably breaks the extension. While with websockets this wont happend.
Has enyone have done something similar?
My team has been using the Web Audio API/Getusermedia in a product and we are going really well with our chrome and firefox users. But we still have a large base of users that we would love to reach, but due to technology barriers, we still can't (mostly, those are IE users), as their main browser does not support the technology, and they do not or can not change to a modern browser.
We are planning to get to those users, but we don't want to go to Flash, Flex, Silverlight or anything similar.
So, thinking about solutions, I thought that maybe I could pass by this difficulty if I moved the audio manipulation, from the browser to the server. NodeJS was the first answer when trying to figure out how to do it.
Would it be possible to be done using NodeJS? Are there any libraries available that would help us accomplish this? Are there any other technologies that would allow me to do this?
Thanks anyone that could help.
It could easily be done. Node is simply an IO engine designed for rapid response. If it needs to happen in real time then I imagine latency would be a usability-breaking issue due to networking restraints. If it doesn't, then I think it would be a great solution! :)
Either way here are a couple related resources
https://www.npmjs.org/package/webrtc.io <- latency optimization library intended for work with media streams
http://wac.ircam.fr/ an upcoming conference (Jan 2015) dedicated to the types of problems you are dealing with.
http://www.sitepoint.com/5-libraries-html5-audio-api/ A few web libraries for use with audio. #3 and #4 look like they are related to what you are trying to do
You can try using this (is in development):
Node Web Audio API
https://github.com/sebpiq/node-web-audio-api
Installation
npm install web-audio-api
Demo
node test/manual-testing/AudioContext-sound-output.js
I'm working on HTML5 app that lets several users to work on one document. I need to add a possibility for users (editing the same document) to talk to each other. And I just don't know how to start with that. Here are my questions
Is there an HTML5 lib allowing to transfer sound from microphone between clients?
What about streaming video from camera?
What is an easiest server-side solution for that?
Any thoughts are strongly appreciated! So don't be shy! :)
UPD: please note that I need an abbility for more then two users to talk.
For this you can use WebRTC.
However, this is a very young and unfinished technology that as already stated is currently available only in Chrome stable and Firefox beta. This means there will probably come changes to the current spec, something to be aware of in case of early implementation. But it allow you to use video and audio communication directly in the browser.
Quick-start here:
http://www.html5rocks.com/en/tutorials/webrtc/basics/
Other options are Flash based plugins such as flash-videoio. This is an open source plugin but will naturally require Adobe Flash installed. This may or may not be a problem depending on the company's security policy.
For technical details on implementation please see examples on the provided links.
For many-to-many you can use either:
"Mesh" - everybody connects to everybody. This however is costly on CPU and mobiles are often left out.
"Star" - everybody goes through the most capable device. However, with many connections this will soon run slow for the device handling all connections.
MCU. Specialized server to handle all connections. If mixes audio and video and handles drop-outs as well without affecting the other callers.
Examples of MCU's:
http://sourceforge.net/projects/mcumediaserver/ (open source)
http://www.medooze.com/products/mcu.aspx (commercial)
you are searching for navigator.getUserMedia()
that allows the various users to share video audio and data.
the support is very low... only chrome and the latest verions of opera and firefox support it.
and totally no support on mobile devices... maybe in the next android chrome... dunno
as there is much to talk about and i have no clue on how u wanna setup everything i suggest u read a little more about that on the urls...
http://caniuse.com/stream
http://www.html5rocks.com/en/tutorials/getusermedia/intro/
http://dev.w3.org/2011/webrtc/editor/getusermedia.html
https://developer.mozilla.org/en-US/docs/WebRTC/navigator.getUserMedia
http://my.opera.com/core/blog/2011/03/23/webcam-orientation-preview
http://simpl.info/getusermedia/
and SERVERSIDE solution nahh... thats not a good solution
clientside is the way to go.
Not sure if you're required to do it yourself from scratch or are able to use third party libraries/tools.
In which case I would recommend using Tokbox which has support for WebRTC and SDK for iOS.
Their API is simple and easy to use.
Is there any way to recognise pen pressure using javascript.
Preferably I don't want to make any use of Flash and try get this done as pure JS.
EDIT: okay I realised that it is kind of possible for Wacom tablets as they come with software that can work with their javascript api to make it possible (demos). But it's no good for people with Trust tablets or any other brand... So no good really.
Any body know how to do it in C# if not JS?
Yes - if the user has a Wacom tablet installed, then their browser will have a plugin for it that you can access. http://www.wacomeng.com/web/index.html
edit from author: I wrote this a very long time ago. Please see the comments below
Microsoft implemented something called Pointer Events in IE 11. It allows you to access pressure property along with stuff like pen tilt and size of contact geometry.
So far it only works on IE11 (and IE10 with vendor prefixes) but there is a W3C candidate recommendation so maybe it will be standard in future.
Javascript as a programming language in itself has no more ability or lack of ability to read this kind of data than any other language.
The language isn't important. What is important are the APIs available to you from within the language.
Javascript can be run in a number of different environments, some of which may possibly have access to APIs for this kind of hardware. However most Javascript is run in a web browser environment, and this is clearly what you mean.
The web browser environment provides a number of APIs. The most obvious is the DOM, which gives you the ability to manipulate the page, etc. There are other APIs available in the browser as well though. For example, the Geolocation API.
All these are standard APIs which have been defined by the W3C (or in some cases are in the process of being defined by the W3C), meaning that all browsers that support them should make them work the same way.
Unfortunately for you there isn't a standard API for working with pressure pads, so the direct answer to your question is no, it can't be done.
Whether one will become available in the future remains to be seen, but I have my doubts.
There is one way that you can do it though: ActiveX.
ActiveX is an API provided by Microsoft in older versions of IE. It basically provides a way of accessing virtually any Windows DLL code from within the browser.
Since the pressure pen device driver for Windows will be provided as a DLL, this means you should theoretically be able to access it in the browser via an ActiveX control. So therefore yes, you would be able to program it using Javascript.
The bad news, though, is that this is not something I'd recommend. ActiveX as a browser-based technology has long since been abandoned, due to the massive security holes it caused. I don't think the latest versions of IE even support it (I hope not, anyway), which means you'd be forced to use old versions of IE (and only IE - no other browser ever supported it) in order to run your code. Not ideal.
No, that's not possible. Probably not even with Flash.
You can only do so in an Native app. Javascript does not have access to pen pressure information
I need to deal with breaking connections and other standard things which are not handled by WebSockets yet. Something tells me that there must be plenty of plugins to do this. Do you use anything like that or write your own routines?
I need it for the client side, since I use Sinatra on the server side.
There are two common issues at hand: supporting older browsers that don't natively support WebSockets and automatic reconnect (in case of breaking connections).
Older browsers are supported by several vendors and products through emulation using different transports - what you need to look at is how good the emulation is. Here's a brief article on the topic describing the problem and Kaazing's solution [disclaimer: I work for Kaazing].
The Kaazing WebSocket Gateway also provides automatic reconnect - in case the connection breaks.
You can download the free developer version of the Kaazing Gateway - to give it a try.