WebSocket whiteboard with chat

http://184.106.155.145/ws.html

by bcardarella • 15 years ago

47 39 15 years ago

184.106.155.145

Just something I built to play around with the tech. Its using EventMachine for the server. Because its only using WebSockets and a more abstract layer like Socket.IO it will only work in Chrome / Safari. (or if you have WebSockets enabled in FireFox but I didn't test it)

The board will auto-clear every 5 minutes.

Have fun!

mtinkerhess• 15 years ago

Pretty cool. It'd be nice if you could change your color -- I was yellow and that was hard to see.

bcardarella13• 15 years ago

The colors are assigned based upon a mod of your SID. So just refresh the page if you want a different color

eik3_de• 15 years ago

Nice alternative: http://mrdoob.com/125/Multiuser_Sketchpad_HTML5

yardie• 15 years ago

Cool. only one wiener on the whiteboard now. I can see this descend into chaos in a few hours.

PHPAdam2• 15 years ago

Its not working for me Brian, which is a shame as I was going to draw some male genitalia.

bcardarella13• 15 years ago

Only works with WebSocket browsers. You'll need Chrome or Safari

nephics• 15 years ago

But it is not working with iPad's safari version

demodifier• 15 years ago

Nice hack. In case you are using Node.js in the back end, you might want to check out socket.io. Provides Websocket support as well fall back transports for browsers that don't support WS.

PHPAdam2• 15 years ago

I got chrome here somewhere, thanks for the TIP.

samtp• 15 years ago

Don't worry, I got you covered

bcardarella13• 15 years ago

Looks like 40 concurrent users is the max. Process crashed but its back up now

kvdr• 15 years ago

Can you spawn a new whiteboard when more than 40 users join?

bcardarella13• 15 years ago

The error was due to a bad string message not parsing properly. I fixed it in the client and should be fine for new users now.

But performance gets pretty crappy at about 40 concurrent users anyway. :p

BuddhaSource• 15 years ago

Really nice to interact live with strangers like this! I always thought HN guys were a bit more matured, it was funny to see every other 2nd doodle was of a dick!

bcardarella13• 15 years ago

I just removed logging, which was causing the process to block so it could write to STDOUT. That should increase performance with tons of users.

xutopia• 15 years ago

I see you are a Rails dev. I imagine in the backend it's something more than a Rails app. What's your stack like?

bcardarella13• 15 years ago

I'm using EventMachine with em-websocket. But I might rewrite it in NodeJS to give that try with Socket.IO

nor-and-or-not• 15 years ago

3 letters: XSS

bcardarella13• 15 years ago

yeah, it was pretty hackish not to plug that. But it should be plugged now

sciolistse• 15 years ago

you might want to escape those text messages.

bcardarella13• 15 years ago

Yeah I know, I was eating lunch when it went crazy

yahelc2• 15 years ago

Wow, so, I might have shut down the whole room by typing in the chat <script>window.close();</script> That room is a giant XSS disaster waiting to happen.

kylemathews• 15 years ago

You did, it closes now almost immediately after opening.

Charybdis• 15 years ago

Yes, you did. I wouldn't recommend going to the site on your own machine because of the security hole. They should fix this as soon as possible.

bcardarella13• 15 years ago

Yeah, I fixed that. It was just a weekend hack. I think the Goatse guy forced my hand

yahelc2• 15 years ago

Thanks for fixing it, and sorry about the window.close() thing :P Very cool; its mind-blowing how simple the code is. Can you post some of the server-side code?

Vivtek• 15 years ago

Fun!

delano• 15 years ago

I took a quick look. It's a cool demo but it's inappropriate to link to it here when there are obvious XSS issues.

bcardarella13• 15 years ago

XSS fixed (I hope)

laskito• 15 years ago

Whiteboard doesn't work very well with trackpads...

tybris• 15 years ago

ok, that's kind of cool. Thanks for fixing the XSS.

stewsnooze• 15 years ago

This is cool. However the HN crowd seem to be just drawing deformed penis pics on it.

robwgibbons• 15 years ago

So fun drawing trollfaces

cookiecaper• 15 years ago

Firefox 4 Beta 8+ users can enable websockets by toggling network.websocket.override-security-block in about:config. It still doesn't work in the latest nightly, though, as I can't draw anything.

Websockets were disabled in Firefox 4b8+ because of supposed security problems in the protocol.

sfphotoarts• 15 years ago

Doesn't work for me Chrome 9.0.597.98 beta on Ubuntu :( Possibly because all HTTP traffic has to go through a proxy server, the company block all outbound traffic, and require a proxy server.

bcardarella13• 15 years ago

The websocket is also on port 8080 so that could be an issue

s_m• 15 years ago

That's awesome – nice work.

WebSocket whiteboard with chat

Related Stories