Objective-C

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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Objective-C

#import <CkoSsh.h>
#import <NSString.h>
#import <CkoStringBuilder.h>

BOOL success = NO;

//  Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
//  appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
//  charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

CkoSsh *ssh = [[CkoSsh alloc] init];

int sshPort = 22;
success = [ssh Connect: @"ssh.example.com" port: [NSNumber numberWithInt: sshPort]];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
NSString *password = @"mySshPassword";

success = [ssh AuthenticatePw: @"mySshLogin" password: password];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

int channelNum = [[ssh OpenSessionChannel] intValue];
if (channelNum < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

success = [ssh SendReqExec: [NSNumber numberWithInt: channelNum] command: @"ls -l /tmp"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
//  it, this call waits forever if the server never sends channel close.
ssh.ReadTimeoutMs = [NSNumber numberWithInt:15000];

success = [ssh ChannelReceiveToClose: [NSNumber numberWithInt: channelNum]];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  Append the received text to a StringBuilder.  Existing content is preserved.
CkoStringBuilder *sb = [[CkoStringBuilder alloc] init];
success = [ssh GetReceivedSb: [NSNumber numberWithInt: channelNum] charset: @"utf-8" sb: sb];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@%d",@"Characters received: ",[sb.Length intValue]);
NSString *output = [sb GetAsString];
NSLog(@"%@",output);

[ssh Disconnect];