PureBasic

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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IncludeFile "CkSFtp.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  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.

    sftp.i = CkSFtp::ckCreate()
    If sftp.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Step 1: Connect the SSH transport.  Port 22 is the usual port.
    port.i = 22
    success = CkSFtp::ckConnect(sftp,"sftp.example.com",port)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    ;  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.s = "mySshPassword"

    success = CkSFtp::ckAuthenticatePw(sftp,"mySshLogin",password)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    ;  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
    ;  file or directory operations.
    success = CkSFtp::ckInitializeSftp(sftp)
    If success = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    ;  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.
    homeDir.s = CkSFtp::ckRealPath(sftp,".","")
    If CkSFtp::ckLastMethodSuccess(sftp) = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    Debug "Home directory: " + homeDir

    ;  Canonicalize a relative path with "..", resolving it to an absolute path.
    resolved.s = CkSFtp::ckRealPath(sftp,"subdir/../otherdir","")
    If CkSFtp::ckLastMethodSuccess(sftp) = 0
        Debug CkSFtp::ckLastErrorText(sftp)
        CkSFtp::ckDispose(sftp)
        ProcedureReturn
    EndIf

    Debug "Resolved path: " + resolved

    CkSFtp::ckDisconnect(sftp)


    CkSFtp::ckDispose(sftp)


    ProcedureReturn
EndProcedure