PowerBuilder

Fetch a Chunk of Messages, Tracking Failures

Demonstrates the Chilkat Imap.FetchChunk2 method, which downloads a run of messages by sequence number and reports which succeeded and which failed. The arguments are the starting sequence number, the count, a MessageSet that receives the failed IDs, a MessageSet that receives the successfully-fetched IDs, and the EmailBundle. This example fetches the first chunk of messages and reports the success and failure counts.

Background: When bulk-downloading a large mailbox, individual messages can occasionally fail to fetch (a corrupt message on the server, a transient error) without failing the whole operation. FetchChunk2 is designed for that reality: it returns a partial EmailBundle plus two MessageSet objects so your code can log or retry exactly the messages that did not come through, rather than aborting the entire sync.

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integer li_rc
integer li_Success
oleobject loo_Imap
integer li_NumMessages
integer li_Count
oleobject loo_FailedSet
oleobject loo_FetchedSet
oleobject loo_Bundle

li_Success = 0

//  Demonstrates the Imap.FetchChunk2 method, which downloads a run of messages by sequence
//  number and reports which succeeded and which failed.  The 1st argument is the starting
//  sequence number, the 2nd is the count, the 3rd receives the failed IDs, the 4th receives
//  the successfully-fetched IDs, and the 5th is the EmailBundle.

loo_Imap = create oleobject
li_rc = loo_Imap.ConnectToNewObject("Chilkat.Imap")
if li_rc < 0 then
    destroy loo_Imap
    MessageBox("Error","Connecting to COM object failed")
    return
end if

loo_Imap.Ssl = 1
loo_Imap.Port = 993

li_Success = loo_Imap.Connect("imap.example.com")
if li_Success = 0 then
    Write-Debug loo_Imap.LastErrorText
    destroy loo_Imap
    return
end if

li_Success = loo_Imap.Login("user@example.com","myPassword")
if li_Success = 0 then
    Write-Debug loo_Imap.LastErrorText
    destroy loo_Imap
    return
end if

li_NumMessages = loo_Imap.SelectMailbox("Inbox")
if li_NumMessages < 0 then
    Write-Debug loo_Imap.LastErrorText
    destroy loo_Imap
    return
end if

//  Fetch messages 1..25 (or fewer if the mailbox is smaller).
li_Count = 25
if li_Count > li_NumMessages then
    li_Count = li_NumMessages
end if

loo_FailedSet = create oleobject
li_rc = loo_FailedSet.ConnectToNewObject("Chilkat.MessageSet")

loo_FetchedSet = create oleobject
li_rc = loo_FetchedSet.ConnectToNewObject("Chilkat.MessageSet")

loo_Bundle = create oleobject
li_rc = loo_Bundle.ConnectToNewObject("Chilkat.EmailBundle")

li_Success = loo_Imap.FetchChunk2(1,li_Count,loo_FailedSet,loo_FetchedSet,loo_Bundle)
if li_Success = 0 then
    Write-Debug loo_Imap.LastErrorText
    destroy loo_Imap
    destroy loo_FailedSet
    destroy loo_FetchedSet
    destroy loo_Bundle
    return
end if

Write-Debug "Fetched: " + string(loo_FetchedSet.Count)
Write-Debug "Failed:  " + string(loo_FailedSet.Count)

li_Success = loo_Imap.Disconnect()
if li_Success = 0 then
    Write-Debug loo_Imap.LastErrorText
    destroy loo_Imap
    destroy loo_FailedSet
    destroy loo_FetchedSet
    destroy loo_Bundle
    return
end if



destroy loo_Imap
destroy loo_FailedSet
destroy loo_FetchedSet
destroy loo_Bundle