What I would like to do is create a canvas that will show a network map. It's not really a network map but in terms of explaining it the network map example works best to not bog you down with details that don't pertain to my question.
On the network map I want to display routes the traffic takes. These routes change in time, sometimes as frequently as multiple times per minute. On the server side I have a log file to which each route change is appended as it happens.
I know how to create the canvas, I know how to draw my routes onto the canvas.
Is it possible to have the server push an update to the canvas without requiring a page reload/refresh, essentially requiring no user interaction at all? The routes drawn just automagically change?
This would need to work on IIS so a jscript or .Net based solution would be necessary. I won't be able to install PHP, Python, Ruby etc.
Thanks in advance for any insights you can provide.
I recommend that you look at a WebSockets solution to push the information from the server to the client (JavaScript). When you receive the update you can update the canvas as required.
Technologies you should look at if your preferred server technology is .NET would be a service like Pusher, who I work for, and our .NET APIs which let you push updates to the client via our REST API.
If you would prefer to host your own realtime infrastructure then you could look at WebSync (which is actually a Comet technology) which integrates with IIS and also XSockets. There are also a number of realtime technologies on this guide which may interest you. If you've any further questions just let me know.
Server-Sent Events: http://www.html5rocks.com/en/tutorials/eventsource/basics
( Server-sent events is a technology for providing push notifications from a server to a browser client in the form of DOM events. The Server-Sent Events EventSource API is now being standardized as part of HTML5[1] by the W3C. )
Yes, I've done this before (with an ajax-based drawing application). It's very possible. Send packets of information via AJAX (JSON or something), interpret them, and draw them on the client's canvas element. This is trivial to design (and easy to implement using something like jQuery). It seems that you already figured out you need to have a server-side script that pushes information to a web page and a web page that actually draws stuff on the canvas. That's essentially all it is.
Related
I'm embedding GMStudio game in browser using . I need to send some data to the game from site's frontend in JSON and to receive some data from the game in frontend to make consequent actions.
So, my idea before was to save data in cookies/localStorage and to get it in the game somehow, using HTTP functionality or DLL's. Also, I'd like to emit messages from the game using window.parent.postMessage and receive them in frontend correctly.
Alas, I did not find a way to implement this. I hope there's some consistent approach to this problem about which I do not know.
The backup plan is to use Game Maker http_post_string and web sockets to get user's data before game's start and to make frontend do something after game's ending. It's clumsy and insecure, however.
The standard approach is to make a JavaScript extension.
That is done by creating a blank extension, adding a blank JS file to it, defining the functions via the context menu on it, and then adding the implementations into the JS file. Then you'll be able to call them from GML side as per usual.
This way you can access LocalStorage\Cookies, transmit\receive data from JS backends, and overall mess with the runtime as you please (with various degrees of understanding required to access internal data).
I have a database of 3D models. I want user can rotate the model and view it in the web page.
So I have to implement an instant rendering algorithm for this.
A raytracing/raycasting method on CPU is preferred since the server has no GPU on it.
I understand that a primary-ray-only ray tracer with SSE and KD-Tree/BVH can be very fast. Besides, I want to add some GI effect(fake GI effect can be also OK for me, such as SSAO) in it.
How good can I achieve?
(some NPR rendering methods are also considerable)
In HTML5, you can render 3D objects with WebGL (an implementation of OpenGL) with some JavaScript. The problem is that WebGL is a client technology. Therefore, all the rendering is done by the browser.
There is one possible solution if you really want to distribute some logic on a server. You could use a server side language and send the vertices to the client through some database transactions. After, your website could make some AJAX calls to a server that would make certain operations within the server and return some vertices. The only problem is that this could require a lot of bandwidth.
Otherwise, another solution would be to use a tool such as Unity to create what you want. Then, you would need to embed the Unity Player in your web page.
I want to make a django server to refresh the content that you approach the database, if the idea is to first make the user see the current contents of the database and as the valley became the new content, this content comes and is placed above the previous content without reloading the page, in another part of the site is to make you change the current content with the new as it gets to the database?
evserver clearer is my choice, but really do not know how and what would be the most simple and efficient?
I think you should avoid HTTP Polling. Here's why:
if the frequency of the setInterval combined with the number of users on your web app is going to lead to a big resource drain. If you go through slides 9 to 19 in this presentation you'll see some quite dramatic figures for using Push (Note: this example uses a hosted service but hosting your own realtime server and using Push also has similar benefits)
between setInterval calls the data displayed in your app is potentially out of data. Using a Push technology means the instant that new data is available it can be push and displayed in your app. You don't want users looking at an app and thinking they are seeing correct information when they are not.
You should take a the following StackOverflow questions:
Django / Comet (Push): Least of all evils?
Need help understanding Comet in Python (with Django)
For Python/Comet see:
Python Comet Server
The latest recommendation for Comet in Python?
I'd recommend you also start considering "WebSockets" as well as "Comet". Most Comet servers now prefer to use a WebSocket connection when possible.
If you'd prefer to avoid installing and managing your own Comet/WebSocket solution then you could use a realtime hosted service which will allow you Push data through them using a REST API and your clients can receive events by embedding a JavaScript library and writing a small about of code to subscribe and receive the event.
The steps are quite straightforward:
Write a model to store data in DB
Write a view that will generate JSON-serialized data upon POST request.
Write a template that will contain JavaScript with setInterval() that will
proceed AJAX requests to the view and render recieved data. (I'd suggest using JQuery as it's well documented and widespread).
I have access to a web interface for a large amount of data. This data is usually accessed by people who only want a handful of items. The company that I work for wants me to download the whole set. Unfortunately, the interface only allows you to see fifty elements (of tens of thousands) at a time, and segregates the data into different folders.
Unfortunately, all of the data has the same url, which dynamically updates itself through ajax calls to an aspx interface. Writing a simple curl script to grab the data is difficult due to this and due to the authentication required.
How can I write a script that navigates around a page, triggers ajax requests, waits for the page to update, and then scrapes the data? Has this problem been solved before? Can anyone point me towards a toolkit?
Any language is fine, I have a good working knowledge of most web and scripting languages.
Thanks!
I usually just use a program like Fiddler or Live HTTP Headers and just watch what's happening behind the scenes. 99.9% of the time you'll see that there's a querystring or REST call with a very simple pattern that you can emulate.
If you need to directly control a browser
Have you thought of using tools like WatiN which are actually used for UI testing purposes but I suppose you could use it to programmaticly make requests anywhere and act upon responses.
If you just need to get the data
But since you can do whatever you please you can just make usual web requests from a desktop application and parse results. You could customize it to your own needs. And simulate AJax requests at will by setting certain request headers.
Maybe this ?
Website scraping using jquery and ajax
http://www.kelvinluck.com/2009/02/data-scraping-with-yql-and-jquery/
I would like to develop a webpage (using any technology) with these conditions:
When client A types the web address on his browser, they automatically receive a remote IP (no other data)
With this IP, Client A automatically request some data from that IP (Client B)
Client B sends the requested information to Client A.
Which technology and libraries could I use to develop this webpage? (Javascript, Applets, browser plugin...) I think is some kind of P2P, so it should be possible to develop it.
Let's put one example.
Imagine that the webpage I have to program is www.hi.com/test.html.
I type it on my browser and receive automatically this IP: 212.22.62.106
My browser automatically request data to 212.22.62.106, which is another client of www.hi.com/test.html
This second client sends me the requested information, which is the only one is shown on my browser.
THANKS
Just about everything in browser security is going to fight this model - Ajax, javascript in general, applets, cookies - they're all tied to the current domain.
To do this, you're going to need to get something onto the desktop, if only in the form of an ActiveX control, which will severely limit your browser-base.
I think you're barking up the wrong tree - maybe if you could pop up one level of abstraction and tell us what you're trying to accomplish with this model?
This is not possible with web page, you're looking in the wrong direction.
You'll have to build your own application which by the way sounds really similar to eMule.. :)