CODEWITHSUNDEEP
iosiphoneobjective-c
Alosyius
Alosyius

Reputation: 9111

iOS socket based chat, how to receive messages that were sent when app is in the background?

For fun I've built a little socket based chat application. It is speaking over tcp socket with a nodejs server. Its successfully sending messages back and forth. However, the problem occurs when i press the home button and put my app in the background - at this point the socket seems to be "paused" and all messages that are sent during this time are lost.

I've got push notifications setup for when the app is in the background but since the socket is not active in the app the message never really reaches the app.

How should i handle this? What are my options? Ive got a few ideas but id love some input here on how people are handling this.

My ideas:

  1. Add a "loadHistory" method on my nodejs server that sends all the history of a channel. So that my app can call a certain URL and get a JSON formated response with all the messages. Maybe this should be done each time a table item is touched?

  2. Make use of the new iOS7 background running features? (Im not to sure its possible to keep the socket alive with that)

  3. Implement a way for the server to know if a message has been delivered, if it could not be delivered it stores the message on the database. As soon as the client goes online again it sends the messages over tcp. This would require a lot of added functionality to the server so id like to avoid this if possible.

Upvotes: 3

Views: 1637

Answers (2)

KudoCC
KudoCC

Reputation: 6952

if you want offline message , the third way is needed, for every message you get, you need to send a notify to the server to tell it the message is delivered , and when you get connected , you should fetch the lost message.

you could use voip, but your app can not receive message if it was killed. (if you add voip mode but your app is not about voice, apple will block your app)

Upvotes: 3

Teena nath Paul
Teena nath Paul

Reputation: 2239

I have also done some work over TCP socket. I gave background support by these steps :

  1. Add "Required background modes" key in your plist file.

    enter image description here

  2. Add this code in your AppDelegate.m file

    - (void)applicationDidEnterBackground:(UIApplication *)application
{
#if __IPHONE_OS_VERSION_MIN_REQUIRED >= 40000
    if([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)] && [[UIDevice currentDevice] isMultitaskingSupported])
    {
        NSLog(@"Keep timeout alive");

        [application setKeepAliveTimeout:600 handler: ^{
            NSLog(@"applicationDidEnterBackground:: setKeepAliveTimeout:handler^");//task as you want to do
        }];
    }

#else
    LogInfo(@"applicationDidEnterBackground (Not supported)");
#endif
}

  3. When you get your read and write CFStream socket object after a successful TCP connection, add this code

    CFReadStreamSetProperty(yourCFReadStreamObj, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);
CFWriteStreamSetProperty(yourCFWriteStreamObj, kCFStreamNetworkServiceType, kCFStreamNetworkServiceTypeVoIP);

After flowwing these steps your socket should receive message in background too and connection will be active till the time you give in "applicationDidEnterBackground".

I hope this will help. Thanks

Upvotes: 1

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