Simple way to send and receive packets?

Could someone please link me to a simple tutorial that allows you to send and receive packets over a web server? All I need to do is be able to send a packet to a certain device with certain contents and have the device checking for new packets every second. Source code would also be helpful. Thanks for t开发者_如何学Gohe help.

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You can look at the documentation for NSConnection, or you can use asihttprequest as a drop-in replacement, which is much better:

http://allseeing-i.com/ASIHTTPRequest/