(Visual FoxPro) 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.

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

LOCAL loImap
LOCAL lnSuccess
LOCAL loJson
LOCAL lnNumThreads
LOCAL loArr
LOCAL lnThreadSize
LOCAL i
LOCAL loSubArr

* 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')
loImap = CreateObject('Chilkat.Imap')

* Connect to your IMAP server and authenticate..
loImap.Ssl = 1
loImap.Port = 993
lnSuccess = loImap.Connect("imap.mail.us-west-2.awsapps.com")
IF (lnSuccess <> 1) THEN
    ? loImap.LastErrorText
    RELEASE loImap
    CANCEL
ENDIF

lnSuccess = loImap.Login("myLogin","myPassword")
IF (lnSuccess <> 1) THEN
    ? loImap.LastErrorText
    RELEASE loImap
    CANCEL
ENDIF

* Select a mailbox
lnSuccess = loImap.SelectMailbox("Inbox")
IF (lnSuccess <> 1) THEN
    ? loImap.LastErrorText
    RELEASE loImap
    CANCEL
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",1)
IF (loImap.LastMethodSuccess = 0) THEN
    ? loImap.LastErrorText
    RELEASE loImap
    CANCEL
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