Objective-C

Bidirectional Sockets (TLS or non-TLS, simultaneous reading and writing a connection)

See more Socket/SSL/TLS Examples

This example demonstrates how to simultaneously read/write on a single socket connection. Objective-C

#import <CkoSocket.h>
#import <CkoTask.h>
#import <NSString.h>

BOOL success = NO;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

CkoSocket *tlsRead = [[CkoSocket alloc] init];

//  We'll just use an HTTPS server for this example...
BOOL bUseTls = YES;
int maxWaitMs = 5000;
success = [tlsRead Connect: @"www.chilkatsoft.com" port: [NSNumber numberWithInt: 443] ssl: bUseTls maxWaitMs: [NSNumber numberWithInt: maxWaitMs]];
if (success == NO) {
    NSLog(@"%@",tlsRead.LastErrorText);
    return;
}

//  Chilkat classes are thread-safe.  This means that only one method call can be active
//  at a time for a given object instance.  It would seem that this would prevent the possibility
//  to simultaneously read/write a given connection because it would require two method calls
//  to be simultaneously active: one for reading and one for writing.
//  
//  There's a trick to doing it...
//  
//  The DupSocket method is provided to get a new object instance that shares the same socket
//  connection.  This allows for the coarse-grained object-level thread safety to be maintained, 
//  while finer-grained thread-safety mechanisms keep things kosher internally.

//  One object will be used for reading, and the cloned socket is used for writing.
//  It doesn't matter which --  you can use the cloned socket for reading or the original for writing.
//  However.. if you try to read simultneously from both the original and cloned objects at the same
//  time, then one will block until the other finishes.  (This is because of the finer-grained thread
//  safety internally.)  The same is true if you try to write both socket objects simultaneously.

CkoSocket *tlsWrite = [[CkoSocket alloc] init];
success = [tlsRead DupSocket: tlsWrite];
if (success == NO) {
    NSLog(@"%@",tlsRead.LastErrorText);
    return;
}

//  Let's start an async read on the socket.  Nothing will be arriving until we actually send the GET
//  request and the server responds.  This will read until the end of the HTTP response header.
CkoTask *task = [tlsRead ReceiveUntilMatchAsync: @"\r\n\r\n"];
[task Run];

//  Now send the request.  This should not block because the read is happening on the tlsRead object.
NSString *httpGetReq = @"GET / HTTP/1.1\r\nHost: www.chilkatsoft.com\r\n\r\n";
success = [tlsWrite SendString: httpGetReq];
//  Assuming success for the example...

//  Wait for the read task to finish.
//  The true/false returned by Wait applies to the Wait method call, not the task.
maxWaitMs = 5000;
success = [task Wait: [NSNumber numberWithInt: maxWaitMs]];
if (!success || ([task.StatusInt intValue] != 7) || (task.TaskSuccess != YES)) {
    if (!success) {
        //  The task.LastErrorText applies to the Wait method call.
        NSLog(@"%@",task.LastErrorText);
    }
    else {
        //  The ResultErrorText applies to the underlying task method call (i.e. the Connect)
        NSLog(@"%@",task.Status);
        NSLog(@"%@",task.ResultErrorText);
    }

    return;
}

//  Examine the received HTTP response header:
NSLog(@"%@",@"HTTP response header:");
NSLog(@"%@",[task GetResultString]);

//  We should get a response that looks like this:
//  	HTTP response header:
//  	HTTP/1.1 200 OK
//  	Cache-Control: private
//  	Content-Length: 7477
//  	Content-Type: text/html
//  	Server: Microsoft-IIS/8.5
//  	Set-Cookie: ASPSESSIONIDSWDSTRTQ=BBNMIKGCHFJNILFFPLDIOGDE; secure; path=/
//  	X-Powered-By: ASP.NET
//  	X-Powered-By-Plesk: PleskWin
//  	Date: Thu, 06 Apr 2017 12:03:30 GMT

//  Forget about the remainder of the HTTP response... The example was only to demonstrate
//  simultaneous reading/writing..
maxWaitMs = 20;
[tlsRead Close: [NSNumber numberWithInt: maxWaitMs]];