Socket disconnect callback

[Sandeep-Appster]

Hi,

We have implemented this library in our project and working fine.

But we are struggling to find out socket disconnect callback/delegate in the app.

Can anyone help how to detect socket disconnect OR is there way to to know what is the function gets called when socket get disconnected?

Thanks

[vivek21feb]

Hi Sandeep,

Have you found the solution?

Thanks

[nneuberger1]

I'm looking for this solution. When the device your connected to immediately disconnects, I would like to know when this happens so we can recover within the application from it. So far, I haven't found an immediate solution on when the socket immediately looses a connection with the other application.

Any ideas?

[saormart]

Same here... Any solution would be appreciated!

[saormart]

I may found a workaround on it by adding a if condition and return "-99" as code to know when you loose the connectivity! I just edited the file: ytcpsocket.c , in the function: "int ytcpsocket_pull(int socketfd, char *data, int len, int timeout_sec) {" at line 107 there's a "do{ ... }" just after the comment: "// use loop to make sure receive all data" so find that "do{ ... }" -> Line: 123 .... so Just after the "} while (readlen > 0);" I added: if(readlen == 0){ return -99 } and after that we have the "return datalen;" Usually the readlen returns "-1" when it has connectivity, but zero (0) when has no connectivity! I have a loop reading all the time anything after connected, so this was my workaround to know if I loose connectivity by server down or so...

[nneuberger1]

Awesome. I will take a look at this solution as well.

We started working an internal "keep alive" type of state check as we're calling a card reader device and sending it a specific command, that the device knows as a "test" command. It either returns or doesn't return and externally from this API, we we're going to fail back and disconnect the socket. I'll give your solution a shot too. thanks!

[saormart]

@nneuberger1 what a such coincidence !? I just used this for my own RFID hardware device that I have designed ! I was using before a hybrid javascript solution, until I started migrating everything to Xcode! So, I'm able to communicate with my hardware with no problem, and some commands that I send like to get the access people list, after the device send me all data from TCP connection, it will drop the connectivity automatically, and with this workaround that I did, I'm able to capture that and let the user know that the connectivity has been terminated! Note: I designed my hardware to wait for the line feed/carriage return, so every command I sent I've added to the "String" the "\r\n", otherwise my device was rejecting it (I could change my device firmware, but due I have multiple software platform running, I just add those to my code and works fine!) Hope this works for you as well! If not, I didn't have time yet to check, but I have the CocoaAsyncSocket in my list to check out if works as well!

[nneuberger1]

I tried your temp fix if(readlen == 0){ return -99 }

But as of right now, I haven't got an immediate callback even though I'm polling in my code. I could be doing something slightly different so I'll keep working on it.

I may try and use CocoaAsyncSocket instead and test it's immediate disconnects. We're using it for other things as well, so I'll report back on that.

[mostlyjason]

I haven't tried the readlen solution, but I just found another solution which is to make the accept call on a loop. If the client attempts to reconnect, the server will know the old one is disconnected and accept the new connection. It works best to dedicate a separate thread since it will block.

queue.async {
    while(true) {
        self.client = self.server.accept(timeout: -1)
        // use the client
    }
}