SQL Server

Email Received Header Fields

Received emails will contain one or more "Received" header fields at the beginning of the email header. Each SMTP server (along the delivery path) adds a Received header to the top of the incoming message. The delivery route can be ascertained by the sequence of Received headers. There is a good summary of the Received header here.

The following explanation is taken from the reference URL above:

In theory, the value of a Received field is tokenizable. It contains

    1) optionally, a "from" atom followed by an encoded domain name;
    2) optionally, a "by" atom followed by an encoded domain name;
    3) optionally, a "via" atom followed by another atom;
    4) zero or more of the following: a "with" atom followed by another atom;
    5) optionally, an "id" atom followed by either (1) an atom or (2) a < token, an encoded address, and a > token;
    6) optionally, a "for" atom followed by an encoded address;
    7) a semicolon; and
    8) a timestamp. 

In practice, SMTP servers put all sorts of badly formatted information into Received lines. It is probably best for readers to treat everything before the final semicolon as unstructured text, purely for human consumption.

This example demonstrates iterating over each of the Recevied headers and getting the content of each.

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
    DECLARE @iTmp0 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 @email int
    EXEC @hr = sp_OACreate 'Chilkat.Email', @email OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Load a .eml file into the email object.
    EXEC sp_OAMethod @email, 'LoadEml', @success OUT, '/home/users/chilkat/eml/myEml.eml'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @email, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @email
        RETURN
      END

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

    DECLARE @i int
    SELECT @i = 0
    DECLARE @numHeaders int
    EXEC sp_OAGetProperty @email, 'NumHeaderFields', @numHeaders OUT
    WHILE @i < @numHeaders
      BEGIN
        EXEC sp_OAMethod @email, 'GetHeaderFieldName', @sTmp0 OUT, @i
        EXEC sp_OAMethod @sbHdrName, 'SetString', @success OUT, @sTmp0
        EXEC sp_OAMethod @sbHdrName, 'ContentsEqual', @iTmp0 OUT, 'Received', 0
        IF @iTmp0 = 1
          BEGIN

            EXEC sp_OAMethod @email, 'GetHeaderFieldValue', @sTmp0 OUT, @i
            PRINT 'Received: ' + @sTmp0
          END
        SELECT @i = @i + 1
      END

    EXEC @hr = sp_OADestroy @email
    EXEC @hr = sp_OADestroy @sbHdrName


END
GO