SQL Server

Upload a Large File in Chunks (FTP)

Demonstrates the Chilkat Ftp2.LargeFileUpload method, which uploads a local file as a sequence of transfers, each up to a given chunk size. The arguments are the local path, the remote path, and the chunk size in bytes.

Note: The local paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Some servers, proxies, or firewalls impose a limit on the size or duration of a single data transfer, which a very large file can exceed. This method sidesteps that by sending the file in pieces — the first with STOR to create or replace the file, each subsequent one appended — so no single transfer is oversized. Choose a chunk size comfortably under whatever limit you are working around.

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SQL Server

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

    --  Demonstrates the Ftp2.LargeFileUpload method, which uploads a local file as a sequence of
    --  transfers, each up to a given chunk size.  The 1st argument is the local path, the 2nd is the
    --  remote path, and the 3rd is the chunk size in bytes.

    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

    --  The first chunk is sent with STOR (creating/replacing the remote file); each later chunk is
    --  appended.  Uploading in chunks can work around server or network limits on a single transfer.
    DECLARE @chunkSize int
    SELECT @chunkSize = 10485760
    EXEC sp_OAMethod @ftp, 'LargeFileUpload', @success OUT, 'qa_data/bigfile.zip', 'uploads/bigfile.zip', @chunkSize
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @ftp, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ftp
        RETURN
      END

    PRINT 'Large file uploaded.'

    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