DataFlex

Open a Remote File on an SFTP Server

Demonstrates the Chilkat SFtp.OpenFile method, which opens or creates a remote file and returns a handle for subsequent read or write operations. The arguments are the remote path, the access mode (readOnly, writeOnly, or readWrite), and the create disposition. Close the handle with CloseHandle when finished.

Background: Handle-based access is the foundation for everything the by-name convenience methods hide. The create disposition is the key control — it decides whether a missing file is an error (openExisting), whether an existing file is truncated (createTruncate) or preserved (openOrCreate), and can add options such as appendData for logging. Because the handle names a server-side resource, it must be closed to avoid exhausting the server's open-file limit.

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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSftp
    Integer iPort
    String sPassword
    String sHandle
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    //  Demonstrates the SFtp.OpenFile method, which opens or creates a remote file and returns a
    //  handle for subsequent read or write operations.  The 1st argument is the remote path, the 2nd
    //  is the access mode, and the 3rd is the create disposition.

    Get Create (RefClass(cComChilkatSFtp)) To hoSftp
    If (Not(IsComObjectCreated(hoSftp))) Begin
        Send CreateComObject of hoSftp
    End

    //  Connect, authenticate, and initialize the SFTP subsystem.
    Move 22 To iPort
    Get ComConnect Of hoSftp "sftp.example.com" iPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  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.
    Move "mySshPassword" To sPassword

    Get ComAuthenticatePw Of hoSftp "mySshLogin" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComInitializeSftp Of hoSftp To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  access must be "readOnly", "writeOnly", or "readWrite".
    //  
    //  createDisposition is a comma-separated list containing exactly one primary disposition:
    //    createNew          Create a new file; fail if it already exists.
    //    createTruncate     Create a new file, or open and truncate an existing file.
    //    openExisting       Open an existing file; fail if it does not exist.
    //    openOrCreate       Open the file if it exists, otherwise create it.
    //    truncateExisting   Open and truncate an existing file; fail if it does not exist.
    //  Optional additional keywords include appendData, textMode, blockRead, blockWrite, and others.

    //  Open a remote file for reading.
    Get ComOpenFile Of hoSftp "subdir/data.txt" "readOnly" "openExisting" To sHandle
    Get ComLastMethodSuccess Of hoSftp To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Opened file, handle = " sHandle

    //  ... read from the handle ...

    //  Always close the handle when finished.
    Get ComCloseHandle Of hoSftp sHandle To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSftp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Send ComDisconnect To hoSftp


End_Procedure