(VBScript) How to Download Messages in MessageSet One at a Time

If a message set contains a huge number of emails, it's NOT a good idea to try to download all at once into an email bundle using a method such as FetchBundle. It's better to iterate over the messages in the set to download one by one.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.Imap")
set imap = CreateObject("Chilkat.Imap")

' Connect using TLS.
imap.Ssl = 1
imap.Port = 993
success = imap.Connect("imap.example.com")
If (success <> 1) Then
    outFile.WriteLine(imap.LastErrorText)
    WScript.Quit
End If

' Authenticate
success = imap.Login("email_account_login","email_account_password")
If (success <> 1) Then
    outFile.WriteLine(imap.LastErrorText)
    WScript.Quit
End If

' Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If (success <> 1) Then
    outFile.WriteLine(imap.LastErrorText)
    WScript.Quit
End If

' Search for messages and return a set of matching messages.
' (This example will simply search for ALL messages.)
fetchUids = 1
' messageSet is a Chilkat.MessageSet
Set messageSet = imap.Search("ALL",fetchUids)
If (imap.LastMethodSuccess <> 1) Then
    outFile.WriteLine(imap.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Number of messages = " & messageSet.Count)

i = 0
Do While i < messageSet.Count
    ' email is a Chilkat.Email
    Set email = imap.FetchSingle(messageSet.GetId(i),fetchUids)
    If (imap.LastMethodSuccess <> 1) Then
        outFile.WriteLine(imap.LastErrorText)

        WScript.Quit
    End If

    outFile.WriteLine(email.From & "; " & email.Subject)

    i = i + 1
Loop

outFile.WriteLine("OK")

outFile.Close