Unicode C

Get Received SSH Bytes into a BinData

Demonstrates the Chilkat Ssh.GetReceivedBd method, which appends the bytes currently in a channel's normal receive buffer to a BinData. The first argument is the channel number and the second is the BinData. The channel receive buffer is cleared afterward; existing bytes in the BinData are preserved.

Background: When the remote command emits binary — a tarball, an image, a compressed stream — decoding it as text through a charset would corrupt it. BinData keeps the bytes exactly as received, so you can write them to a file, hash them, or hand them to another API. Like the StringBuilder form it appends, making it easy to accumulate across successive reads. On failure the BinData is left unchanged.

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Unicode C

#include <C_CkSshW.h>
#include <C_CkBinDataW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSshW ssh;
    int sshPort;
    const wchar_t *password;
    int channelNum;
    HCkBinDataW bd;

    success = FALSE;

    //  Demonstrates the Ssh.GetReceivedBd method, which appends the bytes currently in a channel's
    //  receive buffer to a BinData.  The 1st argument is the channel number and the 2nd is the
    //  BinData.  The channel receive buffer is cleared afterward.

    ssh = CkSshW_Create();

    sshPort = 22;
    success = CkSshW_Connect(ssh,L"ssh.example.com",sshPort);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        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.
    password = L"mySshPassword";

    success = CkSshW_AuthenticatePw(ssh,L"mySshLogin",password);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    channelNum = CkSshW_OpenSessionChannel(ssh);
    if (channelNum < 0) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    //  Run a command whose output may be binary.
    success = CkSshW_SendReqExec(ssh,channelNum,L"cat /usr/bin/hostname");
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        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.
    CkSshW_putReadTimeoutMs(ssh,15000);

    success = CkSshW_ChannelReceiveToClose(ssh,channelNum);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        return;
    }

    //  Append the raw received bytes to a BinData.  Existing bytes in the BinData are preserved.
    bd = CkBinDataW_Create();
    success = CkSshW_GetReceivedBd(ssh,channelNum,bd);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSshW_lastErrorText(ssh));
        CkSshW_Dispose(ssh);
        CkBinDataW_Dispose(bd);
        return;
    }

    wprintf(L"Bytes received: %d\n",CkBinDataW_getNumBytes(bd));

    CkSshW_Disconnect(ssh);


    CkSshW_Dispose(ssh);
    CkBinDataW_Dispose(bd);

    }