C++

Resolve an Absolute Remote Path with SFTP RealPath

Demonstrates the Chilkat SFtp.RealPath method, which asks the server to canonicalize a path and returns the resulting absolute remote path. The first argument is the original path and the second is an optional compose path (SFTP v5 or later); pass an empty string when no composition is needed.

Background: The server — not the client — owns the remote filesystem's layout, so path canonicalization must happen on the server. RealPath resolves ., .., and symbolic links into a single absolute path, which is the reliable way to learn the session's home directory (canonicalize .) or to turn a relative path into an absolute one before storing or displaying it. On SFTP v5 and later, the compose path can additionally join or override the original.

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#include <CkSFtp.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  Demonstrates the SFtp.RealPath method, which asks the server to canonicalize a path and
    //  returns the resulting absolute remote path.  The 1st argument is the original path and the
    //  2nd is an optional compose path (SFTP v5+), which may be an empty string.

    CkSFtp sftp;

    //  Step 1: Connect the SSH transport.  Port 22 is the usual port.
    int port = 22;
    success = sftp.Connect("sftp.example.com",port);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        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.
    const char *password = "mySshPassword";

    success = sftp.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
    //  file or directory operations.
    success = sftp.InitializeSftp();
    if (success == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    //  Resolve "." to the absolute path of the session's default (home) directory.  No compose path
    //  is needed, so the 2nd argument is an empty string.
    const char *homeDir = sftp.realPath(".","");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Home directory: " << homeDir << "\r\n";

    //  Canonicalize a relative path with "..", resolving it to an absolute path.
    const char *resolved = sftp.realPath("subdir/../otherdir","");
    if (sftp.get_LastMethodSuccess() == false) {
        std::cout << sftp.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Resolved path: " << resolved << "\r\n";

    sftp.Disconnect();
    }