SQL Server

XML Inclusive Canonicalization

See more XML Digital Signatures Examples

Demonstrates how to convert XML to the Inclusive XML Canonicalization form as specified in http://www.w3.org/TR/xml-c14n/ SQL Server

-- 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)
    DECLARE @success int
    SELECT @success = 0

    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    -- The XML digital signature verification class provides utility methods for
    -- XML canonicalization.  This example demonstrates how to do inclusive XML canonicalization.

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

    DECLARE @sbXml int
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbXml OUT

    DECLARE @canon int
    EXEC @hr = sp_OACreate 'Chilkat.XmlDSig', @canon OUT

    -- Use inclusive XML canonicalization.
    DECLARE @canonVersion nvarchar(4000)
    SELECT @canonVersion = 'C14N'
    DECLARE @withComments int
    SELECT @withComments = 0

    DECLARE @url nvarchar(4000)
    SELECT @url = 'https://www.chilkatsoft.com/exampleData/c14n/test7.xml'
    EXEC sp_OAMethod @http, 'QuickGetSb', @success OUT, @url, @sbXml

    -- This is the input XML:
    -- The XML comment is referring to when exclusive XML canonicalization is applied.  With inclusive canonicalization, the namespace nodes
    -- are kept, as we'll see below..

    -- <doc>
    -- <!-- A namespace node N is ignored if the nearest ancestor element of the node's parent element that is in the node-set has a namespace node in the node-set with the same local name and value as N. -->
    -- 	<animal xmlns:aa="https://www.animal.com/">
    -- 		<reptile xmlns:bb="https://www.reptile.com/">
    --   			<lizard xmlns="" type="african fat tailed" abc="xyz" xmlns:aa="https://www.animal.com/" />
    --   			<snake type="poisonous rattler" xmlns:bb="https://www.reptile.com/" >
    --   			</snake>
    --   		</reptile>
    --   	</animal>
    -- </doc>

    DECLARE @xmlInclCanon nvarchar(4000)
    EXEC sp_OAMethod @sbXml, 'GetAsString', @sTmp0 OUT
    EXEC sp_OAMethod @canon, 'CanonicalizeXml', @xmlInclCanon OUT, @sTmp0, @canonVersion, @withComments

    PRINT @xmlInclCanon

    -- The C14N (inclusive) canonicalization is:

    -- <doc>
    -- 
    -- 	<animal xmlns:aa="https://www.animal.com/">
    -- 		<reptile xmlns:bb="https://www.reptile.com/">
    --   			<lizard abc="xyz" type="african fat tailed"></lizard>
    --   			<snake type="poisonous rattler">
    --   			</snake>
    --   		</reptile>
    --   	</animal>
    -- </doc>

    -- To see the difference, let's do exclusive canonicalization..
    SELECT @canonVersion = 'EXCL_C14N'

    DECLARE @xmlExclCanon nvarchar(4000)
    EXEC sp_OAMethod @sbXml, 'GetAsString', @sTmp0 OUT
    EXEC sp_OAMethod @canon, 'CanonicalizeXml', @xmlExclCanon OUT, @sTmp0, @canonVersion, @withComments

    PRINT @xmlExclCanon

    -- // The C14N (exclusive) canonicalization is:
    -- 
    -- <doc>
    -- 
    -- 	<animal>
    -- 		<reptile>
    --   			<lizard abc="xyz" type="african fat tailed"></lizard>
    --   			<snake type="poisonous rattler">
    --   			</snake>
    --   		</reptile>
    --   	</animal>
    -- </doc>

    EXEC @hr = sp_OADestroy @http
    EXEC @hr = sp_OADestroy @sbXml
    EXEC @hr = sp_OADestroy @canon


END
GO