(Objective-C) Multiple SendReqExec on Same Connection

Shows how to execute a series of commands on an SSH server and retrieve each command's output (using SendReqExec). Each call to SendReqExec requires its own logical channel. This is not a separate SSH connection -- it's simply a new session channel on the existing SSH connection.

Chilkat Objective-C Library Downloads MAC OS X (Cocoa) Libs iOS Libs

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

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

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

// Hostname may be an IP address or domain:
NSString *hostname = @"172.16.16.46";
int port = 22;

BOOL success = [ssh Connect: hostname port: [NSNumber numberWithInt: port]];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// If receiving output from a command stalls for more than 5 seconds, then stop waiting.
ssh.IdleTimeoutMs = [NSNumber numberWithInt:5000];

// Authenticate using login/password:
success = [ssh AuthenticatePw: @"myLogin" password: @"myPassword"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Open a session channel.  (It is possible to have multiple
// session channels open simultaneously.)
int channelNum = [[ssh OpenSessionChannel] intValue];
if (channelNum < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Request a directory listing on the remote server:
// If your server is Linux/UNIX, change the string from "dir" to "ls"
// Note: Some SSH servers require a CRLF instead of a bare-LF
NSString *cmd = @"ls -al\n";
success = [ssh SendReqExec: [NSNumber numberWithInt: channelNum] command: cmd];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Read whatever output may already be available on the
// SSH connection.  ChannelReadAndPoll returns the number of bytes
// that are available in the channel's internal buffer that
// are ready to be "picked up" by calling GetReceivedText
// or GetReceivedData.
// A return value of -1 indicates failure.
// A return value of -2 indicates a failure via timeout.

// The ChannelReadAndPoll method waits
// for data to arrive on the connection usingi the IdleTimeoutMs
// property setting.  Once the first data arrives, it continues
// reading but instead uses the pollTimeoutMs passed in the 2nd argument:
// A return value of -2 indicates a timeout where no data is received.
int pollTimeoutMs = 2000;
int n = [[ssh ChannelReadAndPoll: [NSNumber numberWithInt: channelNum] pollTimeoutMs: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
if (n < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

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

// Perhaps we did not receive all of the commands output.
// To make sure,  call ChannelReceiveToClose to accumulate any remaining
// output until the server's corresponding "channel close" is received.
success = [ssh ChannelReceiveToClose: [NSNumber numberWithInt: channelNum]];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Get the accumulated output of the command:
NSString *cmdOutput = 0;
cmdOutput = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"ansi"];
if (ssh.LastMethodSuccess == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Display the remote shell's command output:
NSLog(@"%@",cmdOutput);
NSLog(@"%@",@"----");

// -----------------------------------------------------------------
// Now for the 2nd SendReqExe (on the same connection,
// but on a separate logical channel).
// -----------------------------------------------------------------

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

cmd = @"nslookup chilkatsoft.com\n";
success = [ssh SendReqExec: [NSNumber numberWithInt: channelNum] command: cmd];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

pollTimeoutMs = 2000;
n = [[ssh ChannelReadAndPoll: [NSNumber numberWithInt: channelNum] pollTimeoutMs: [NSNumber numberWithInt: pollTimeoutMs]] intValue];
if (n < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

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

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

cmdOutput = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"ansi"];
if (ssh.LastMethodSuccess == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@",cmdOutput);