(SQL Server) Get the Last-Modified Date Before HTTP Download

Demonstrates how to send a HEAD request to get the last-modified date of a file on a web server (without downloading the file).

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
    DECLARE @iTmp0 int
    DECLARE @iTmp1 int
    DECLARE @iTmp2 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    DECLARE @http int
    -- Use "Chilkat_9_5_0.Http" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Http', @http OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @resp int
    EXEC sp_OAMethod @http, 'GetHead', @resp OUT, 'https://www.chilkatsoft.com/hamlet.xml'
    EXEC sp_OAGetProperty @http, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @http, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @http
        RETURN
      END

    -- Examine the response header.
    EXEC sp_OAGetProperty @resp, 'Header', @sTmp0 OUT
    PRINT @sTmp0

    -- Here is a sample response header:

    -- 	Content-Length: 279658
    -- 	Content-Type: text/xml
    -- 	Last-Modified: Thu, 12 May 2016 15:14:08 GMT
    -- 	Accept-Ranges: bytes
    -- 	ETag: "c1cd8bee60acd11:0"
    -- 	Server: Microsoft-IIS/8.5
    -- 	X-Powered-By: ASP.NET
    -- 	X-Powered-By-Plesk: PleskWin
    -- 	Date: Thu, 25 Jul 2019 16:40:54 GMT

    -- Get the Last-Modified header.
    DECLARE @lastModStr nvarchar(4000)
    EXEC sp_OAMethod @resp, 'GetHeaderField', @lastModStr OUT, 'Last-Modified'
    -- If the header exists...
    EXEC sp_OAGetProperty @resp, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 1
      BEGIN
        -- Parse the RFC822 format date/time string
        DECLARE @ckdt int
        -- Use "Chilkat_9_5_0.CkDateTime" for versions of Chilkat < 10.0.0
        EXEC @hr = sp_OACreate 'Chilkat.CkDateTime', @ckdt OUT

        DECLARE @success int
        EXEC sp_OAMethod @ckdt, 'SetFromRfc822', @success OUT, @lastModStr

        -- If we want to access individual date/time parts (in the local timezone)
        DECLARE @dt int
        EXEC sp_OAMethod @ckdt, 'GetDtObj', @dt OUT, 1

        EXEC sp_OAGetProperty @dt, 'Day', @iTmp0 OUT

        EXEC sp_OAGetProperty @dt, 'Month', @iTmp1 OUT

        EXEC sp_OAGetProperty @dt, 'Year', @iTmp2 OUT
        PRINT 'day/month/year = ' + @iTmp0 + '/' + @iTmp1 + '/' + @iTmp2
        EXEC @hr = sp_OADestroy @dt

      END
    EXEC @hr = sp_OADestroy @resp


    EXEC @hr = sp_OADestroy @http
    EXEC @hr = sp_OADestroy @ckdt


END
GO