(Objective-C) SSH Remote Shell

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output.

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#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 hostname:
NSString *hostname = @"www.some-ssh-server.com";
int port = 22;

// Connect to an SSH server:
BOOL success = [ssh Connect: hostname port: [NSNumber numberWithInt: port]];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Wait a max of 5 seconds when reading responses..
ssh.IdleTimeoutMs = [NSNumber numberWithInt:5000];

// Authenticate using login/password:
success = [ssh AuthenticatePw: @"myLogin" password: @"myPassword"];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

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

// Some SSH servers require a pseudo-terminal
// If so, include the call to SendReqPty.  If not, then 
// comment out the call to SendReqPty.
// Note: The 2nd argument of SendReqPty is the terminal type,
// which should be something like "xterm", "vt100", "dumb", etc.
// A "dumb" terminal is one that cannot process escape sequences.
// Smart terminals, such as "xterm", "vt100", etc. process
// escape sequences.  If you select a type of smart terminal,
// your application will receive these escape sequences
// included in the command's output.  Use "dumb" if you do not
// want to receive escape sequences.  (Assuming your SSH
// server recognizes "dumb" as a standard dumb terminal.)
NSString *termType = @"dumb";
int widthInChars = 120;
int heightInChars = 40;
// Use 0 for pixWidth and pixHeight when the dimensions
// are set in number-of-chars.
int pixWidth = 0;
int pixHeight = 0;
success = [ssh SendReqPty: [NSNumber numberWithInt: channelNum] xTermEnvVar: termType widthInChars: [NSNumber numberWithInt: widthInChars] heightInRows: [NSNumber numberWithInt: heightInChars] pixWidth: [NSNumber numberWithInt: pixWidth] pixHeight: [NSNumber numberWithInt: pixHeight]];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Start a shell on the channel:
success = [ssh SendReqShell: [NSNumber numberWithInt: channelNum]];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Start a command in the remote shell.  This example
// will send a "ls" command to retrieve the directory listing.
success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: @"ls\r\n" charset: @"ansi"];
if (success != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Send an EOF.  This tells the server that no more data will 
// be sent on this channel.  The channel remains open, and
// the SSH client may still receive output on this channel.
success = [ssh ChannelSendEof: [NSNumber numberWithInt: channelNum]];
if (success != YES) {
    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 n;
int pollTimeoutMs = 2000;
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 != YES) {
    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 != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

// Let's pickup the accumulated output of the command:
NSString *cmdOutput = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"ansi"];
if (ssh.LastMethodSuccess != YES) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

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

// Disconnect
[ssh Disconnect];