How can I code a web app p2p network?

I wanted to code a web application, where one user can choose a file and o开发者_开发问答ther multiple users can download that specified file off of that user's computer. That user would have to leave his computer on and leave the web page open.

I dont want to have a big main server that has to handle all that traffic. That user's computer is the server, persay. I understand I'll use torrent.

All this has to be done on a website.

Will a web socket work?

Please and Thanks.

This really isn't possible for a variety of reasons:

• Firewalls / NATs
• Dynamic IPs
• No "server" running on the user's machines
• Permissions on the user's machine
• What happens if the user simply deletes the file on their machine?

To actually make it work you'd have to:

• Convince the user to install the app on their machine (you'd need a windows/linux/... EXE)
• Get the user to open a port in the firewall (or use some library to enable NAT passthru)
• Have the user's PC ping your server in the event the user's IP changes

On the server side, you'd have to keep several database tables, here are few I can think of off the top of my head:

• A user's table (user ID [PK], Current IP, Communications Port, (maybe some other tracking things))
• Available downloads table (download ID [PK], user ID [FK])

Then when someone wants to go off and download, you have to (probably) launch your app with the requisite arguments (remote user's IP/port/file ID) and have that do the work of the download.

This is by no means an easy feat.

If by WebSockets you mean the HTML5 variety, I'd stay away from that. http://en.wikipedia.org/wiki/WebSockets#Browser_support

The the computer that has to stay on, is basically your server. Even if it isn't a big server somewhere.

My suggestion would be to install apache or some other small web server on each users computer and have have a dyndns address for each computer so you can find each other. it would be much easier than coding something. especially if it has to be through a web page.

You could use a c# client library to interface to bittorrent or etc and use this mode to upload/leach. As far as NAT/Firewall issues go they are well documented and a function of the protocol being used, ie deal with it.