SQL Server

DNS Query MX Records

See more DNS Examples

Shows how to perform a DNS query to retrieve MX records.

Note: This example requires Chilkat v9.5.0.96 or later.

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

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

    DECLARE @json int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json OUT

    EXEC sp_OASetProperty @json, 'EmitCompact', 0

    EXEC sp_OAMethod @dns, 'Query', @success OUT, 'MX', 'somebody@gmail.com', @json
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @dns, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @dns
        EXEC @hr = sp_OADestroy @json
        RETURN
      END

    EXEC sp_OAMethod @json, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    -- Sample response.
    -- Parsing code below..

    -- -------------------------------------------------------------------------------
    -- Note: Chilkat will return the results sorted by "pref" from lowest to highest.
    -- -------------------------------------------------------------------------------

    -- {
    --   "answer": {
    --     "mx": [
    --       {
    --         "name": "gmail.com",
    --         "ttl": 491,
    --         "pref": 5,
    --         "domain": "gmail-smtp-in.l.google.com"
    --       },
    --       {
    --         "name": "gmail.com",
    --         "ttl": 491,
    --         "pref": 10,
    --         "domain": "alt1.gmail-smtp-in.l.google.com"
    --       },
    --       {
    --         "name": "gmail.com",
    --         "ttl": 491,
    --         "pref": 20,
    --         "domain": "alt2.gmail-smtp-in.l.google.com"
    --       },
    --       {
    --         "name": "gmail.com",
    --         "ttl": 491,
    --         "pref": 30,
    --         "domain": "alt3.gmail-smtp-in.l.google.com"
    --       },
    --       {
    --         "name": "gmail.com",
    --         "ttl": 491,
    --         "pref": 40,
    --         "domain": "alt4.gmail-smtp-in.l.google.com"
    --       }
    --     ]
    --   }
    -- }

    -- Use this online tool to generate parsing code from sample JSON: 
    -- Generate Parsing Code from JSON

    DECLARE @name nvarchar(4000)

    DECLARE @ttl int

    DECLARE @pref int

    DECLARE @domain nvarchar(4000)

    DECLARE @i int
    SELECT @i = 0
    DECLARE @count_i int
    EXEC sp_OAMethod @json, 'SizeOfArray', @count_i OUT, 'answer.mx'
    WHILE @i < @count_i
      BEGIN
        EXEC sp_OASetProperty @json, 'I', @i
        EXEC sp_OAMethod @json, 'StringOf', @name OUT, 'answer.mx[i].name'
        EXEC sp_OAMethod @json, 'IntOf', @ttl OUT, 'answer.mx[i].ttl'
        EXEC sp_OAMethod @json, 'IntOf', @pref OUT, 'answer.mx[i].pref'
        EXEC sp_OAMethod @json, 'StringOf', @domain OUT, 'answer.mx[i].domain'
        SELECT @i = @i + 1
      END

    EXEC @hr = sp_OADestroy @dns
    EXEC @hr = sp_OADestroy @json


END
GO