SQL Server
SQL Server
S3 Resume Download
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Suppose an S3 download of a very large file failed for some reason and you have a partial file on disk. Rather than restart the entire download, you wish to download the remaining portion. This example demonstrates how to finish a previously failed download.Note: This example requires Chilkat v9.5.0.83 or above.
Chilkat SQL Server Downloads
-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
DECLARE @hr int
DECLARE @iTmp0 int
-- Important: Do not use nvarchar(max). See the warning about using nvarchar(max).
DECLARE @sTmp0 nvarchar(4000)
DECLARE @success int
SELECT @success = 0
-- This example requires the Chilkat API to have been previously unlocked.
-- See Global Unlock Sample for sample code.
DECLARE @rest int
EXEC @hr = sp_OACreate 'Chilkat.Rest', @rest OUT
IF @hr <> 0
BEGIN
PRINT 'Failed to create ActiveX component'
RETURN
END
-- Connect to the Amazon AWS REST server.
DECLARE @bTls int
SELECT @bTls = 1
DECLARE @port int
SELECT @port = 443
DECLARE @bAutoReconnect int
SELECT @bAutoReconnect = 1
EXEC sp_OAMethod @rest, 'Connect', @success OUT, 's3.amazonaws.com', @port, @bTls, @bAutoReconnect
-- ---------------------------------------------------------------------------
-- Important: For buckets created in regions outside us-east-1,
-- there are three important changes that need to be made.
-- See Working with S3 Buckets in Non-us-east-1 Regions for the details.
-- ---------------------------------------------------------------------------
-- Provide AWS credentials for the REST call.
DECLARE @authAws int
EXEC @hr = sp_OACreate 'Chilkat.AuthAws', @authAws OUT
EXEC sp_OASetProperty @authAws, 'AccessKey', 'AWS_ACCESS_KEY'
EXEC sp_OASetProperty @authAws, 'SecretKey', 'AWS_SECRET_KEY'
EXEC sp_OASetProperty @authAws, 'ServiceName', 's3'
EXEC sp_OAMethod @rest, 'SetAuthAws', @success OUT, @authAws
-- Set the bucket name via the HOST header.
-- In this case, the bucket name is "chilkat100".
EXEC sp_OASetProperty @rest, 'Host', 'chilkat100.s3.amazonaws.com'
-- We want to continue downloading a file.
-- The relative local filepath of our previously partially downoaded file is: qa_output/hamlet.xml
-- Let's find out how many bytes are already downloaded.
DECLARE @fac int
EXEC @hr = sp_OACreate 'Chilkat.FileAccess', @fac OUT
DECLARE @localFilepath nvarchar(4000)
SELECT @localFilepath = 'qa_output/hamlet.xml'
-- Note: The FileSize method returns a signed 32-bit integer. If the file is potentially larger than 2GB, call FileSizeStr instead to return
-- the size of the file as a string, then convert to an integer value.
DECLARE @sz int
EXEC sp_OAMethod @fac, 'FileSize', @sz OUT, @localFilepath
IF @sz > 0
BEGIN
PRINT 'sz = ' + @sz
-- If the sz equals 42375 bytes, then we want to add a Range header that looks like this:
-- Range: bytes=42375-
DECLARE @sbRange int
EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbRange OUT
EXEC sp_OAMethod @sbRange, 'Append', @success OUT, 'bytes='
EXEC sp_OAMethod @sbRange, 'AppendInt', @success OUT, @sz
EXEC sp_OAMethod @sbRange, 'Append', @success OUT, '-'
EXEC sp_OAMethod @sbRange, 'GetAsString', @sTmp0 OUT
EXEC sp_OAMethod @rest, 'AddHeader', @success OUT, 'Range', @sTmp0
EXEC sp_OAMethod @sbRange, 'GetAsString', @sTmp0 OUT
PRINT 'Added Range: ' + @sTmp0
END
-- Send the request to download the remainder of the file.
EXEC sp_OAMethod @rest, 'SendReqNoBody', @success OUT, 'GET', '/hamlet.xml'
IF @success <> 1
BEGIN
EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
PRINT @sTmp0
EXEC @hr = sp_OADestroy @rest
EXEC @hr = sp_OADestroy @authAws
EXEC @hr = sp_OADestroy @fac
EXEC @hr = sp_OADestroy @sbRange
RETURN
END
-- Read the response header.
DECLARE @responseStatusCode int
EXEC sp_OAMethod @rest, 'ReadResponseHeader', @responseStatusCode OUT
IF @responseStatusCode < 0
BEGIN
EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
PRINT @sTmp0
EXEC @hr = sp_OADestroy @rest
EXEC @hr = sp_OADestroy @authAws
EXEC @hr = sp_OADestroy @fac
EXEC @hr = sp_OADestroy @sbRange
RETURN
END
PRINT 'Response status code = ' + @responseStatusCode
-- We expect a 200 or 206 response status if the file data is coming.
-- Otherwise, we'll get a string response body with an error message(or no response body).
IF (@responseStatusCode = 200) or (@responseStatusCode = 206)
BEGIN
DECLARE @bodyStream int
EXEC @hr = sp_OACreate 'Chilkat.Stream', @bodyStream OUT
-- The stream's sink will be a file.
-- We will append to the file..
EXEC sp_OASetProperty @bodyStream, 'SinkFile', @localFilepath
-- Indicate that we wish to append to the output file.
-- The SinkFileAppend property was added in Chilkat v9.50.83
EXEC sp_OASetProperty @bodyStream, 'SinkFileAppend', 1
-- Read the response body to the stream. Given that we've
-- set the stream's sink to a file, it will stream directly
-- to the file.
EXEC sp_OAMethod @rest, 'ReadRespBodyStream', @success OUT, @bodyStream, 1
IF @success <> 1
BEGIN
EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
PRINT @sTmp0
EXEC @hr = sp_OADestroy @rest
EXEC @hr = sp_OADestroy @authAws
EXEC @hr = sp_OADestroy @fac
EXEC @hr = sp_OADestroy @sbRange
EXEC @hr = sp_OADestroy @bodyStream
RETURN
END
PRINT 'Successfully downloaded the file.'
END
ELSE
BEGIN
DECLARE @errResponse nvarchar(4000)
EXEC sp_OAMethod @rest, 'ReadRespBodyString', @errResponse OUT
EXEC sp_OAGetProperty @rest, 'LastMethodSuccess', @iTmp0 OUT
IF @iTmp0 <> 1
BEGIN
EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
PRINT @sTmp0
END
ELSE
BEGIN
PRINT @errResponse
END
END
EXEC @hr = sp_OADestroy @rest
EXEC @hr = sp_OADestroy @authAws
EXEC @hr = sp_OADestroy @fac
EXEC @hr = sp_OADestroy @sbRange
EXEC @hr = sp_OADestroy @bodyStream
END
GO