(Lianja) IMAP Search with THREAD Semantics

Demonstrates how to search an IMAP mailbox and return message numbers grouped together in parent/child relationships based on which messages are replies to others.

Note: This example requires Chilkat v9.5.0.77 or greater.

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

loImap = createobject("CkImap")

// Connect to your IMAP server and authenticate..
loImap.Ssl = .T.
loImap.Port = 993
llSuccess = loImap.Connect("imap.mail.us-west-2.awsapps.com")
if (llSuccess <> .T.) then
    ? loImap.LastErrorText
    release loImap
    return
endif

llSuccess = loImap.Login("myLogin","myPassword")
if (llSuccess <> .T.) then
    ? loImap.LastErrorText
    release loImap
    return
endif

// Select a mailbox
llSuccess = loImap.SelectMailbox("Inbox")
if (llSuccess <> .T.) then
    ? loImap.LastErrorText
    release loImap
    return
endif

// Search for all message having the letter 'a' somewhere in the Subject,
// and return the messages as JSON.
loJson = loImap.ThreadCmd("REFERENCES","UTF-8","SUBJECT a",.T.)
if (loImap.LastMethodSuccess = .F.) then
    ? loImap.LastErrorText
    release loImap
    return
endif

// The IMAP server will return a raw response with a format such as this:  (2)(3 6 (4 23)(44 7 96))

// In tree form, it's like this:
// 
//             -- 2
//             -- 3
//                 \-- 6
//                    |-- 4
//                    |      \-- 23
//                    |
//                    |-- 44
//                               \-- 7
//                                       \-- 96
// 

// It means there are 2 main threads returned, but the 2nd thread splits into two sub-threads.
// In total, we can think of it as 3 threads -- 2 main threads (with no parents) and one sub-thread w/ a parent.
// 
// - The 1st thread contains the message 2, and has no parent thread.
// - The 2nd thread contains the messages 3, 6, 4, 23, and has no parent thread.
// - The 3rd thread contains the messages 44, 7, 96 and the parent thread is message 6.
// 

// (Yes, this is all highly confusing...)

// Chilkat will return the above sample response as JSON that looks like this:

// {
//   "threads": [
//     [2],
//     [3, 6, [4, 23], [44, 7, 96]]
//   ]
// }
// 

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON
// In this case, the online tool can help you get a feel for how to write the JSON parsing code..

lnNumThreads = loJson.SizeOfArray("threads")
? "The total number of top-level threads is " + str(lnNumThreads)

// Let's say we wanted to get the messages in the thread 3, 6, 4, 23.
// We always follow the 1st branch to the bottom, ignoring the other branches.
// For example, if we had  [3, 5, [4, 23, [55, 56, 57], [68, 69]], [44, 7, 96]]
// then the thread would be 3, 5, 4, 43, 55, 56, 57

// For testing, let's substitute the response from the IMAP server with this sample:
loJson.Load('{"threads": [[2], [3, 5, [4, 23, [55, 56, 57], [68, 69]], [44, 7, 96]]]}')

// Begin with the 2nd top-level thread, which is at index 1.
? "Following the 2nd top level thread..."
loArr = loJson.ArrayOf("threads[1]")
lnThreadSize = loArr.Size
i = 0
do while i < lnThreadSize
    // Do we have an array or integer at this position?
    if (loArr.TypeAt(i) = 4) then
        // This is a sub-array.
        loSubArr = loArr.ArrayAt(i)
        release loArr
        // Follow the sub-array starting at the 1st position..
        loArr = loSubArr
        i = 0
        lnThreadSize = loArr.Size
    else
        // Must be a single integer.
        ? str(loArr.IntAt(i))
        i = i + 1
    endif

enddo

release loJson

// The output is:
// 
// Following the 2nd top level thread...
// 3
// 5
// 4
// 23
// 55
// 56
// 57


release loImap