I'm kind of curious how I should approach a problem with iPhones and communication between two phones.
I have an idea for an application that needs to send data between two known phones. The problem is that the data could be very small or very large. I want to have intermediate storage on a server and a messaging layer, but I want there to be performant means to communicate between devices for shorter, unimportant messages.
You always hear about networking and client to client communication with popular platforms and protocols, but I'm curious what people's thoughts are on doing p2p style communication with an iPhone.
I'm pretty sure it should (and can) be treated as just a simple addressable machine... so I would have to build NAT traversing network code into the iPhone itself. A thought I had would be some sort of UPnP situation where I would ask to NAT a particular port for communication to the devices... but I guess I could just as easily turn it into a polling situation.
Granted, I understand that Apple will have a "push" mechanism for developers eventually but I want to get the app out the door before hand...
Just curious about thoughts on this type of thing... any thoughts on multi-player game situations would also directly apply to (and benefit from) this question.
Have you given the WiTap sample from Apple a try? It addresses the issue of discoverability (via Bonjour) and connectivity (via basic TCP). It may not be as robust as what you are looking for, but it's worth a look:
http://developer.apple.com/iphone/library/samplecode/WiTap/index.html
Look at the docs for Game Kit in the iPhone 3.0 SDK. It allows iPhones to connect to one another locally with Bluetooth, or via wi-fi/3G. It addresses both peer-to-peer and client-server architectures. It provides unreliable and reliable links.
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I need to develop an app where several ipads communicate to a single main iPad. Would this be done using Bonjour or Game Kit? I looked at Bluetooth but that seems like a 1 to 1 communication. I have never messed with either of these API's
You could use Bonjour to do this -- but remember that Bonjour is only a framework to advertise services and doesn't do any of the actual connection itself.
For Bonjour, you need to create an NSNetServicesBrowser to scan the network (which can use Bluetooth -- or WiFi) and publish an NTNetService with the port for the other iPads to connect to (this could be the "master" iPad itself).
Then you would need to run a server on the "master" iPad (that is advertising the service) and then have some sockets code to handle all of that. (For which I recommend AsyncSocket (http://code.google.com/p/cocoaasyncsocket/).
Let me know if this is something you would be interested in doing, and I would be able to provide some code snippets as a starting point...
Like Glycerin said earlier, take a look at WebSockets. You can choose to have one-to-one, one-to-many, many-to-many connections, and is insanely fast.
Here's a tutorial on Nettuts
WebSockets are the way to go. I would suggest learning about the basics of sockets, there are implementation in most programming languages. This helped me a lot: http://beej.us/guide/bgnet/ After getting a understanding of what sockets are and what they do u could use the CocoaAsyncSocket-Framework http://code.google.com/p/cocoaasyncsocket/ on iOS. It adds an additional level of abstraction to sockets that helps especially with non-blocking network communication. There is some sample code available.
What would be the best method to achieve realtime device to device communication within an application? I've been experimenting with the Apple Push Notification Service but find it spotty at best for realtime messaging. Is there a way to utilize sockets for this or am I just stuck into using the APNS?
If you are a beginner, use GameKit.
When you get sick of that, use AsyncSocket.
GameKit is so simple a child can use it; AsyncSocket is probably the most beautiful library in all of networking on any platforms - incredibly easy to use.
In both cases, you will first use Bonjour (two lines of code) to "find" the other device.
Here is the full explanation...
Tablet(iPad/Android)-Server Communication Protocol
Critical secret knowledge about GK you will need...
Client/Server GKSessions
Another quick summary ...
Most effective way to do networking on Mac/iPhone?
For the record, APNS has absolutely nothing whatsoever to do with what you are trying to achieve! Utterly forget about APNS.
WHAT IS THE RADIUS? -----------------------***
Please note that BLUETOOTH ONLY WORKS over about twenty feet. (Ten meters.)
Please note that for a local WiFi connection, you must both be connected to the same local WiFi hub. WiFi hubs have a range of perhaps 20 meters only, say one house and the next house only (depending on how thick the walls are).
Please note that: IT IS NOT PHYSICALLY POSSIBLE TO CONNECT TWO COMPUTERS (OF ANY TYPE) OVER A COUPLE OF MILES.
There is no such networking device. (You could perhaps build one using say "ham radio" but to be clear it would be a completely novel, new research project that would take a large company years to complete.)
There is absolutely nothing that works like that - I'm sorry to tell you the bad news.
The ONLY two possibilties are Bluetooth and WiFi, and they work only over about 20 and 30 feet respectively.
So how do you connect two remote computers like that? The answer is, via the internet.
The only way to do it is with an internet connection. There is no 'direct' connection possible with any existing technology.
If you need to know more about how to connect two computers (say two iPhones) using the internet, you will probably have to ask a new question! You will be pleased to know it is very easy and will cause you little trouble.
Note that both iPhones MUST have a good solid internet connection. If they are more than say 30 feet away from each other, the ONLY way to connect to iPhones is via the internet. THey must each have a good internet connection, or there is no possibility.
I hope this helps clarify things!
You can use GameKit's peer to peer services (bluetooth)
Gamekit how to do p2p wifi connection in iphone
Check out Apples GameKit framework GameKit Or a sockets based networking look at AsyncSocket which also includes an iPhone demo.
I'm trying to write a simple chat application for the iPhone (as an experiment). Is there a simple way for two devices to discover each others' IP addresses, and given the addresses is there a simple API or protocol that would let me send text messages back and forth?
I've investigated SIP (specifically Sofia and eXosip), but these tools exist as C libraries and are beyond my current ability to port them to the iPhone.
Update: I'm trying to connect two devices over the Internet (i.e. not over Bluetooth or a local wireless network, which is what GameKit does).
You're going to need a server that provides the match making service. Game Center makes this pretty easy, but your users will have to have Game Center accounts.
Alternatively, you can set up an XMPP (formerly Jabber, it's what powers Google Chat) server (I've never done this, but there are several available) and use the XMPP Framework for Cocoa. There are instructions for using it in iPhone apps here.
I'm sure there are other chat servers and client source also available. IRC and Mobile Colloquy come to mind.
Finally, you could write your own server using your favorite server language / framework. This isn't too hard (I've done it myself), but it's far from what I'd call simple, and I wouldn't use it for a production system.
There is support for exactly this kind of ad-hoc peer-to-peer networking in GameKit. Have a look at the second half of the GameKit documentation for details:
http://developer.apple.com/library/ios/#documentation/...
NSNetService is a good option.
Take a look at WebRTC Datachannels. WebRTC is a newer option with native iOS support a standard that is still being finalized, but it is more flexible should the iOS app need to communicate with browser or even android peers
I'm just getting started with mobile development, and after considerable searching I'm still confused about sending a message from my iPhone to another or an Android. For instance, in building a simple Tic-Tac-Toe game, if I want to notify the other phone of a move, what is the best way to do so? Wifi, bluetooth, 3G? And how?
Many methods seem to point to communicating through a web server, but I'd rather send them directly from phone to phone if possible. (this is for native apps of course)
If you don't want to have a server (or even if you do! It depends!) it sounds like you will want to use TCP sockets. Apple doesn't have a generic bluetooth API to use with iPhone-to-android communication and you'll have TCP access anyway with 3G. A 3G network connection is very similar to wifi and you should be able to check for the difference as needed with little change to your overall networking code. I'm not sure if bonjour is supported on android, but I bet someone has ported it for similar reasons already, and it is supported in iOS. Apple has a networking section for iOS that you may find informative.
Additionally if you want to stay within the iOS device only realm you could use GameKit to communicate via bluetooth.
Hope that helps some.
The easiest way is to create a web server with an API and the clients poll the server for new moves (or the server pushes the client an update). This is the only way you're going to be able to do it over 3G unless you can figure out the IP addresses of both phones (do phones even keep the same IP address for a long period of time?) and open up sockets between them and let one phone be the server and the other be the client (could cause potential cheating).
WiFi is not always there - by limiting your users' options to areas with access points, you'll lose sales. Not sure about Bluetooth - how prevalent is it on handsets, how much of the API is exposed. Your best bet, IMHO, is 3G. With some kind of a central presence server (Web or otherwise), with optional proxying. Read up on peer-to-peer networking.
As far as i know does the iphone only support incoming messages over push notifications.
This means, that you have to update the information, by requesting it from web services etc.
The bluetooth API of the iphone doesn't support this either.
Based on a college-project I'm trying to realize a relatively simple game (Poker) where an iPad acts as Server and multiple iPod-Touchs connect to it as Clients.
Gamekit seems to drop out, since those old ipod-touch-devices don't have bluetooth-support.
Are there already some Frameworks out there simplifying the process, or do I have to fall back on TCP-Streaming-Sockets and implement it myself?
For your task I suggest you have a look at ThoMoNetworking or AsyncSocket.
ThoMoNet is a very simple setup that is specifically developed for fast and easy prototyping and easy to set up. Is will automatically create a bi-partite graph between all instances of you application it finds in the local network. So If you keep your iPad as the server and the iPhones as clients this will come down to less than 10 lines of code to set up.
AsyncSocket is a commonly used framework with ports to PC as well but requires more code to write. On the other hand it will allow you to do more fancy things, should you need them.
Distributed objects are not yet available on iPhone OS, so excluding GameKit you may try using Bonjour networking. Otherwise, you may try using web services with some of the available libraries. If Bonjour and web services are not a choice/possibility, then you have to revert to old plain sockets.