SQL Server

Clear the FTP Directory Listing Cache

Demonstrates the Chilkat Ftp2.ClearDirCache method, which clears the cached listing for the current remote directory. It takes no arguments; the next indexed-listing call fetches a fresh listing from the server.

Background: The index-based directory API caches the listing the first time you read it, so repeated accessor calls avoid extra round trips. The trade-off is staleness: if the directory changes — files added or removed, whether by your own operations or another process — the cache still reflects the old state. ClearDirCache discards it so the next GetDirCount queries the server again.

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--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Demonstrates the Ftp2.ClearDirCache method, which clears the cached listing for the current
    --  remote directory.  It takes no arguments and is a void method.

    DECLARE @ftp int
    EXEC @hr = sp_OACreate 'Chilkat.Ftp2', @ftp OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OASetProperty @ftp, 'Hostname', 'ftp.example.com'
    EXEC sp_OASetProperty @ftp, 'Username', 'myFtpLogin'

    --  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.
    EXEC sp_OASetProperty @ftp, 'Password', 'myPassword'

    EXEC sp_OAMethod @ftp, 'Connect', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ftp
        RETURN
      END

    EXEC sp_OAMethod @ftp, 'ChangeRemoteDir', @success OUT, 'public_html'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ftp
        RETURN
      END

    --  The first GetDirCount caches the listing.
    DECLARE @n int
    EXEC sp_OAMethod @ftp, 'GetDirCount', @n OUT

    PRINT 'Entries: ' + @n

    --  ... the remote directory changes (files added or removed by another process) ...

    --  Discard the cache so the next listing call fetches fresh data from the server.
    EXEC sp_OAMethod @ftp, 'ClearDirCache', NULL

    EXEC sp_OAMethod @ftp, 'GetDirCount', @n OUT

    PRINT 'Entries after refresh: ' + @n

    EXEC sp_OAMethod @ftp, 'Disconnect', @success OUT
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ftp
        RETURN
      END

    EXEC @hr = sp_OADestroy @ftp


END
GO