Recently I wrote a BizTalk Server 2006 custom pipeline component to resolve a custom party on the POP3.From context value when an email was received. I was surprised to find some unusual behaviour if the POP3.From context value contained square brackets like “HEWHOCARES [WORLD]” < HEWHOCARES@world.com >. I describe the behaviour and why it occurs below because it took me by surprise.
The base example for the custom pipeline component is based on http://msdn.microsoft.com/en-us/library/aa559134.aspx . The code fragment below shows the important changes;
/// This function gets called after the entire stream of the message has been read, guaranteeing that all promoted properties
/// from the message have been populated to the message context.
/// </summary>
internal void EndOfStream()
{
string FromEmail = null;
BizTalkParty party;
//obtain the FromEmail string from the message
FromEmail = (string)mBaseMessage.Context.Read(“From”, “http://schemas.microsoft.com/BizTalk/2003/pop3-properties”);
if (FromEmail != null)
{
PartyResolver pr = new PartyResolver();
party = pr.GetPartyFromAlias(“FromEmail”, “FromEmailName”, FromEmail);
mBaseMessage.Context.Promote(“SourcePartyID”, “http://schemas.microsoft.com/BizTalk/2003/system-properties”, party.SID);
mBaseMessage.Context.Promote(“PartyName”, “http://schemas.microsoft.com/BizTalk/2003/messagetracking-properties”, party.Name);
}
}
I set up my party like; 
On testing this pipeline component with an email from “HEWHOCARES” < HEWHOCARES@world.com > it resolves the party to ThePeopleWhoCare. Now if I change the party value to “HEWHOCARES [WORLD]” < HEWHOCARES@world.com > and send an email from the same email address then it resolves to Guest not ThePeopleWhocare. What is going on? If you dig a bit further you find that to resolve the party this stored procedure is used;
USE [BizTalkMgmtDb]
GO
/****** Object: StoredProcedure [dbo].[admsvr_GetPartyByAliasNameValue] Script Date: 03/24/2009 21:16:03 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[admsvr_GetPartyByAliasNameValue]
@nvcAliasName nvarchar(256),
@nvcAliasQualifier nvarchar(64),
@nvcAliasValue nvarchar(256),
@nvcSID nvarchar(256) OUTPUT,
@nvcName nvarchar(256) OUTPUT
AS
SELECT @nvcSID = bts_party.nvcSID,
@nvcName = bts_party.nvcName
FROM bts_party, bts_party_alias
WHERE UPPER(bts_party_alias.nvcName) = UPPER(@nvcAliasName) AND
UPPER(bts_party_alias.nvcQualifier) = UPPER(@nvcAliasQualifier) AND
bts_party_alias.nvcValue LIKE @nvcAliasValue AND
bts_party_alias.nPartyID = bts_party.nID
The WHERE clause uses a LIKE statement for the criteria based on the passed POP3.FROM context value. [] in a like statement is evaluated as any single character within the specified range. Thus in our case we try find a party with an FromEmail value of “HEWHOCARES W” < HEWHOCARES@world.com > (or where W” is O”, R”, L” or D”). Indeed if I now change the party value to “HEWHOCARES W” < HEWHOCARES@world.com > then “HEWHOCARES [WORLD]” < HEWHOCARES@world.com > resolves to ThePeopleWhoCare once again.
