与 iPhone 进行点对点聊天

Question

I am aware of how many times this has been asked based on searching StackOverflow, but I am still hoping someone could tell me whether I am wrong...

I am creating a peer-to-peer chat app for the iPhone. My initial idea was to avoid using a server, so Bonjour came to mind. I was happy coding for quite a while and implemented a lot of fancy features, but two days ago I started testing with two clients from different subnets and found that the clients couldn't connect to each other. I suddenly realized that Bonjour is meant for local networks and that a DNS server is necessary for wide area service broadcasting? Do I really need a server for Internet peer-to-peer chat? Are there any other options that do not involve using a server on the iOS platform?

Answer 1

To answer the question, the only way is for you to carry a list of all possible participants, and their current IP address, and for each possible participant to report to all others each time their IP Address changes. So, if you have 100 possible participants, then you must tell 99 others when your IP Address changes, and those 99 must tell you when their IP Address changes.

Bonjour may work on a LAN, a WAN or even a WAN, but it will never work on the internet.

The role of the server is so that each end point only need to tell one end point (the server) when it changes. My advice is get a cheap internet host, with a basic PHP / MySQL capabilities, and write yourself a very simple script to post and get user identities.

Answer 2

I am wondering how you can do a chat app without using a server. There are many cheap solutions out there, Amazon has its own service, Google does as well. You can try first without even having to pay a cent.

Answer 3

I found the following from apple developer guide. This should answer your question -

1. Does Bonjour work between multiple subnets?

Yes. The first release of DNS Service Discovery (DNS-SD) for Mac OS X concentrated on Multicast DNS (mDNS) for single-link networks because this was the environment worst served by IP software. Starting in Mac OS X 10.4, Bonjour now uses Dynamic DNS Update (RFC 2316) and unicast DNS queries to enable wide-area service discovery.