Objective-C

Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method. Objective-C

#import <CkoSocket.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 *sock = [[CkoSocket alloc] init];

//  --------------------------------------------------------------------
//  This example uses the public TCP echo service at https://tcpbin.com/
//  --------------------------------------------------------------------

BOOL useTls = NO;
int port = 4242;
int maxWaitMs = 5000;
success = [sock Connect: @"tcpbin.com" port: [NSNumber numberWithInt: port] ssl: useTls maxWaitMs: [NSNumber numberWithInt: maxWaitMs]];
if (success == NO) {
    NSLog(@"%@",sock.LastErrorText);
    return;
}

//  Wait a max of 2 seconds for a response..
sock.MaxReadIdleMs = [NSNumber numberWithInt:2000];

//  Send some strings, each terminated by a 0 byte.
[sock SendString: @"This is the 1st string"];
[sock SendByte: [NSNumber numberWithInt: 0]];
[sock SendString: @"This is string number 2"];
[sock SendByte: [NSNumber numberWithInt: 0]];

//  The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
[sock SendByte: [NSNumber numberWithInt: 10]];

//  Now let's receive what is echoed back....
//  Receive each string and the NULL byte.
//  The call to ReceiveStringUntilByte will receive incoming data until the lookForByte is encountered.
//  The lookForByte is receive and discarded (it is not returned in the string)
int lookForByte = 0;
NSString *s1 = [sock ReceiveStringUntilByte: [NSNumber numberWithInt: lookForByte]];
if (sock.LastMethodSuccess == NO) {
    NSLog(@"%@",sock.LastErrorText);
    return;
}

NSLog(@"%@",s1);

NSString *s2 = [sock ReceiveStringUntilByte: [NSNumber numberWithInt: lookForByte]];
if (sock.LastMethodSuccess == NO) {
    NSLog(@"%@",sock.LastErrorText);
    return;
}

NSLog(@"%@",s2);

//  The echo server will also echo back the final LF
[sock ReceiveByte: YES];
maxWaitMs = 100;
[sock Close: [NSNumber numberWithInt: 100]];

//  Output:
//  This is the 1st string
//  This is string number 2