(SQL Server) S3 Get Object Metadata, such as ETag

Demonstrates how to get an S3 object's metadata using a HEAD request.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @rest int
    -- Use "Chilkat_9_5_0.Rest" for versions of Chilkat < 10.0.0
    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 in the desired region.
    -- In this case we connect to S3 in the "us-west-2" region.
    DECLARE @bTls int
    SELECT @bTls = 1
    DECLARE @port int
    SELECT @port = 443
    DECLARE @bAutoReconnect int
    SELECT @bAutoReconnect = 1
    DECLARE @success int
    EXEC sp_OAMethod @rest, 'Connect', @success OUT, 's3-us-west-2.amazonaws.com', @port, @bTls, @bAutoReconnect

    -- Provide AWS credentials.
    DECLARE @authAws int
    -- Use "Chilkat_9_5_0.AuthAws" for versions of Chilkat < 10.0.0
    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'

    -- This particular bucket is in the Oregon region, as opposed to the US Standard,
    -- therefore the Region must be set appropriately.
    -- Also note that we connected to "s3-us-west-2.amazonaws.com".
    EXEC sp_OASetProperty @authAws, 'Region', 'us-west-2'

    EXEC sp_OAMethod @rest, 'SetAuthAws', @success OUT, @authAws

    -- Note: The above REST connection and setup of the AWS credentials
    -- can be done once.  After connecting, any number of REST calls can be made.
    -- The "auto reconnect" property passed to rest.Connect indicates that if
    -- the connection is lost, a REST method call will automatically reconnect
    -- if needed.
    -- --------------------------------------------------------------------------

    -- Set the bucket name via the HOST header.
    -- In this case, the bucket name is "chilkat.ocean".
    -- Note that the Host header should use "bucketName.s3.amazonaws.com", not "bucketName.s3-us-west-2.amazonaws.com"
    EXEC sp_OASetProperty @rest, 'Host', 'chilkat.ocean.s3.amazonaws.com'

    -- Our object is "starfish.jpg".
    -- Get the metadata.
    -- Since we are sending a HEAD request, we shouldn't use any of the Full* methods.
    -- Instead, send the request, then just read the response header.
    EXEC sp_OAMethod @rest, 'SendReqNoBody', @success OUT, 'HEAD', '/starfish.jpg'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @authAws
        RETURN
      END

    -- Now get the response header.
    DECLARE @statusCode int
    EXEC sp_OAMethod @rest, 'ReadResponseHeader', @statusCode OUT
    IF @statusCode < 0
      BEGIN
        EXEC sp_OAGetProperty @rest, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @authAws
        RETURN
      END

    -- When successful, the S3 Storage service will respond with a 200 response code,
    -- with an XML body.  
    IF @statusCode <> 200
      BEGIN
        -- Examine the request/response to see what happened.

        PRINT 'response status code = ' + @statusCode

        EXEC sp_OAGetProperty @rest, 'ResponseStatusText', @sTmp0 OUT
        PRINT 'response status text = ' + @sTmp0

        EXEC sp_OAGetProperty @rest, 'ResponseHeader', @sTmp0 OUT
        PRINT 'response header: ' + @sTmp0
        EXEC @hr = sp_OADestroy @rest
        EXEC @hr = sp_OADestroy @authAws
        RETURN
      END

    -- The response header contains information about the S3 object.
    -- For example:

    -- 	HTTP/1.1 200 OK
    -- 	x-amz-id-2: GrV/hrB2EUkBlWc0h3JDdmVIrYDXfPC7CGvo/qSVRmYRPwilAOry8+4r2YWl4xJfa1HRYXrP808=
    -- 	x-amz-request-id: 4BDC6D6AEA0BDEF3
    -- 	Date: Mon, 13 May 2019 22:03:13 GMT
    -- 	Last-Modified: Mon, 10 Nov 2014 16:10:23 GMT
    -- 	ETag: "2e9c59dbf2662367dc97dfdda85da048"
    -- 	Accept-Ranges: bytes
    -- 	Content-Type: image/jpg
    -- 	Content-Length: 6229
    -- 	Server: AmazonS3

    -- Get the ETag response header value:
    DECLARE @etag nvarchar(4000)
    EXEC sp_OAMethod @rest, 'ResponseHdrByName', @etag OUT, 'ETag'

    PRINT 'ETag: ' + @etag

    EXEC @hr = sp_OADestroy @rest
    EXEC @hr = sp_OADestroy @authAws


END
GO