(SQL Server) Decode 2-digit Hex Escaped

Demonstrates how to replace escaped us-ascii chars such as \x7b and \x22 with the chars.

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)
    -- We have the following string with some us-ascii chars escaped like this:
    DECLARE @s nvarchar(4000)
    SELECT @s = '\x7b\x22responseContext\x22:\x7b\x22'

    -- Note: The above escaping does not conform to any standard format (as far as I know).
    -- Chilkat does not have anything to decode from the above.
    -- However, we can 1st transform into a standard format, and then decode..

    -- JSON escapes chars outside us-ascii like this:  "Hello, \ud83d\ude03!"
    -- We can transform the above to this:  "\u007b\u0022responseContext\u0022:\u007b\u0022"
    -- And then decode..

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

    DECLARE @success int
    EXEC sp_OAMethod @sb, 'Append', @success OUT, @s
    DECLARE @numReplaced int
    EXEC sp_OAMethod @sb, 'Replace', @numReplaced OUT, '\x', '\u00'

    -- Now decode from "json" escapes
    EXEC sp_OAMethod @sb, 'Decode', @success OUT, 'json', 'utf-8'

    -- Show the decoded string
    EXEC sp_OAMethod @sb, 'GetAsString', @sTmp0 OUT
    PRINT @sTmp0

    -- Here's the result: {"responseContext":{"

    EXEC @hr = sp_OADestroy @sb


END
GO