SSH to a Cisco Switch - Processing "More" Responses

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Demonstrates connecting to a Cisco switch, entering privileged mode with the ena command, and running a command whose response is paged. Each page ends with --More-- and requires a SPACE character to request the next page.

Note: QuickShell allocates a PTY, which is what a network device console expects. The device presents an interactive prompt, and each command's output is read up to the next prompt.

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

BOOL success = NO;

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

//  Demonstrates connecting to a Cisco switch, entering privileged mode, and running a command
//  whose response is paged -- each page ends with "--More--" and requires a SPACE character to
//  request the next page.

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

int port = 22;
success = [ssh Connect: @"172.16.16.100" port: [NSNumber numberWithInt: port]];
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 QuickShell] intValue];
if (channelNum < 0) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  IMPORTANT: Set a read timeout before receiving until a match.  ReadTimeoutMs defaults to 0,
//  which means no limit -- without it, this call waits forever if the received data never
//  contains a match.
ssh.ReadTimeoutMs = [NSNumber numberWithInt:15000];

BOOL caseSensitive = YES;

//  In unprivileged mode the switch prompt ends with ">".
success = [ssh ChannelReceiveUntilMatch: [NSNumber numberWithInt: channelNum] matchPattern: @">" charset: @"utf-8" caseSensitive: caseSensitive];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSString *received = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"utf-8"];
if (ssh.LastMethodSuccess == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@",received);

//  Send "ena" to enter privileged mode.  Cisco devices expect a bare CR to terminate a command.
success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: @"ena\r" charset: @"utf-8"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

success = [ssh ChannelReceiveUntilMatch: [NSNumber numberWithInt: channelNum] matchPattern: @"Password:" charset: @"utf-8" caseSensitive: caseSensitive];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

received = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"utf-8"];
if (ssh.LastMethodSuccess == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@",received);

//  The enable password is separate from the login password, and likewise should come from a
//  secure source rather than being hard-coded.
NSString *enablePassword = @"myEnablePassword";
success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: enablePassword charset: @"utf-8"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: @"\r" charset: @"utf-8"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  In privileged mode the prompt ends with "#" instead of ">".
success = [ssh ChannelReceiveUntilMatch: [NSNumber numberWithInt: channelNum] matchPattern: @"#" charset: @"utf-8" caseSensitive: caseSensitive];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

received = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"utf-8"];
if (ssh.LastMethodSuccess == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

NSLog(@"%@",received);

//  Run a command whose output is delivered a page at a time.
success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: @"show running-config\r" charset: @"utf-8"];
if (success == NO) {
    NSLog(@"%@",ssh.LastErrorText);
    return;
}

//  Each read ends either at the device prompt (output complete) or at "--More--" (another page
//  is waiting).  Match the full prompt rather than a bare "#", because "#" also appears inside
//  configuration text and would match too early.
CkoStringArray *saMatch = [[CkoStringArray alloc] init];
[saMatch Append: @"MySwitchName#"];
[saMatch Append: @"--More--"];

CkoStringBuilder *sbReceived = [[CkoStringBuilder alloc] init];
BOOL moreComing = YES;

while (moreComing) {
    success = [ssh ChannelReceiveUntilMatchN: [NSNumber numberWithInt: channelNum] matchPatterns: saMatch charset: @"utf-8" caseSensitive: caseSensitive];
    if (success == NO) {
        NSLog(@"%@",ssh.LastErrorText);
        return;
    }

    [sbReceived Clear];
    NSString *pageText = [ssh GetReceivedText: [NSNumber numberWithInt: channelNum] charset: @"utf-8"];
    if (ssh.LastMethodSuccess == NO) {
        NSLog(@"%@",ssh.LastErrorText);
        return;
    }

    [sbReceived Append: pageText];
    NSLog(@"%@",pageText);

    //  If this page ended with "--More--", send a SPACE to request the next page.
    moreComing = [sbReceived Contains: @"--More--" caseSensitive: caseSensitive];
    if (moreComing) {
        success = [ssh ChannelSendString: [NSNumber numberWithInt: channelNum] strData: @" " charset: @"utf-8"];
        if (success == NO) {
            NSLog(@"%@",ssh.LastErrorText);
            return;
        }

    }

}

[ssh Disconnect];