DataFlex

Verify Email Recipients Without Sending

Demonstrates the Chilkat MailMan.VerifyRecips method, which begins the SMTP send process for an email, sends the recipient addresses to the SMTP server, and then aborts before sending the message content. Recipient addresses rejected by the server are returned in the StringArray. This example checks two recipients and lists any that were rejected.

Background: During an SMTP transaction each recipient is offered with a RCPT TO command, and the server accepts or rejects it before any message content is transferred. VerifyRecips exploits that: it runs the transaction just far enough to collect those verdicts, then aborts — letting you validate an address list without actually delivering mail. Note that many servers accept everything at this stage and bounce later, so a clean result is not a guarantee of deliverability.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoMailman
    Variant vEmail
    Handle hoEmail
    Variant vBadAddrs
    Handle hoBadAddrs
    Integer n
    Integer i
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the MailMan.VerifyRecips method, which begins the SMTP send process for an
    //  email, sends the recipient addresses to the SMTP server, and then aborts before sending
    //  the message content.  Recipient addresses rejected by the server are returned in the
    //  StringArray.

    Get Create (RefClass(cComChilkatMailMan)) To hoMailman
    If (Not(IsComObjectCreated(hoMailman))) Begin
        Send CreateComObject of hoMailman
    End

    //  Configure the SMTP server connection.
    Set ComSmtpHost Of hoMailman To "smtp.example.com"
    Set ComSmtpPort Of hoMailman To 465
    Set ComSmtpSsl Of hoMailman To True
    Set ComSmtpUsername Of hoMailman To "user@example.com"
    Set ComSmtpPassword Of hoMailman To "myPassword"

    //  Build an email with the recipients to verify.
    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End
    Set ComSubject Of hoEmail To "Recipient check"
    Set ComFrom Of hoEmail To "alice@example.com"
    Get ComAddTo Of hoEmail "Bob" "bob@example.com" To iSuccess
    Get ComAddTo Of hoEmail "Nobody" "nobody@example.com" To iSuccess

    //  Ask the server which recipients it will accept.  Rejected addresses are returned.
    Get Create (RefClass(cComCkStringArray)) To hoBadAddrs
    If (Not(IsComObjectCreated(hoBadAddrs))) Begin
        Send CreateComObject of hoBadAddrs
    End
    Get pvComObject of hoEmail to vEmail
    Get pvComObject of hoBadAddrs to vBadAddrs
    Get ComVerifyRecips Of hoMailman vEmail vBadAddrs To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoMailman To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComCount Of hoBadAddrs To n
    Showln "Rejected recipients: " n

    For i From 0 To (n - 1)
        Get ComGetString Of hoBadAddrs i To sTemp1
        Showln sTemp1
    Loop

    //  Note: Explicitly connecting/authenticating is optional.  Chilkat MailMan automatically
    //  connects and authenticates -- using the property settings above -- whenever a server
    //  operation requires it.  Calling the explicit connect/authenticate methods can still be
    //  helpful to determine whether a failure occurs while connecting or while authenticating.


End_Procedure