Which network protocol to use to sync resources between a server a several clients

Question

I am building a professional iOS application where an iPad is a server and several iPhones are clients.

Considering the fact that : - communications operate only on a local network via sockets using TCP. - I want to keep all of them in sync (all devices have a local database) - I want to be able to send commands like NEW, UPDATE, DELETE, etc to keep them in sync - I want be able to send notifications with some data attached (audio file), - I want to define priorities for all of theses commands.

It makes me think that a need to define a protocol, so my question is : Does one already exist ?

Thanks a lot !

Answer 1

You can listen socket messages, server can send simple structs with data url, commands to clients, and after that they can update data for example:

#define MSG_DOWNLOAD 1

typedef struct{
   uint8_t cmd;
   uint8_t size;
} MSGHEADER

typdef struct{
   MSGHEADER header;
   char url[255];
} MSGDOWNLOAD;

and in socket if you will get header with cmd = 1, you can send NSURLconnetion with url to your server and download some data and sync it.

- (void)recivedDataFromBuffer:(NSData *)data
{

    MSGHEADER *pMsgHdr;
    pMsgHdr = (MSGHEADER*)[data bytes];

    int headerCMD = pMsgHdr->cmd;

    if (headerCMD == MSG_DOWNLOAD)
    {
        MSGDOWNLOAD download = *(MSGDOWNLOAD *)pMsgHdr;
        download.header = *pMsgHdr;

        // do sync stuff send url request etc.
    }