How to use labels in Gmail to identify single messages instead of threads that have already been processed by a script

Question

Using google script for google mail, I'm trying to upload new emails with certain labels to our CRM using an API. I can't check if messages have been uploaded already, so I have to apply a label in the mailbox to messages that have been processed before.

Unfortunately, google script only lets you add or check labels on a thread level. Since new messages can come in for a thread after it has last been uploaded to the CRM, I don't know what messages of a thread have actually been processed already.

The Code below contains what I had in mind, the function getLabels does not work for Message however so it does not work.

Hope somebody has a smart solution!

Thanks

//execute main sequence
function collecttobesend() {
    var labeladd = GmailApp.getUserLabelByName("add to CRM");
    var labeladded = GmailApp.getUserLabelByName("added to CRM");
    //var threads = label.getThreads();
    var threads = GmailApp.search('label:added-to-crm -label:add-to-crm')

    for (var i = 0; i < threads.length; i++) {
        thread = threads[i];

        // get all messages in a given thread
        var messages = thread.getMessages();

        // iterate over each message
        for (var j = 0; j < messages.length; j++) {
            message = messages[j];
            var labels = message.getLabels();
            var messagehaslabeladded = false;

            for (var k = 0; k < labels.length; k++) {
                if (labels[k] = labeladded) {
                    messagehaslabeladded = true;
                }
            }

            // if message has not been added yet
            if (messagehaslabeladded = false) {
                var success = false;

                //add to CRM through API
                success = true;

                //if succesfull add label
                if (success = true) {
                    message.addLabel(labeladded);
                }
            }
        }
    }

I just encountered the same problem. And then found a contradictory statement on the Gmail search query help > Note: Labels are only added to a message, and not an entire > conversation My experience is directly the opposite, the API only allows me to get labels at the conversation level, not the individual message level. I'll try to get someone from Support to comment — Le Stephane
Got a notification of your comment. I actually found a solution, see answer below. — John Willson

HDCerberus HDCerberus · Accepted Answer · 2014-11-21T20:11:42

Tricky.

Your problem as I see it is twofold.

1) If a thread receives a response after the 'added to CRM' label has been applied, then that new message won't even trigger the check if it needs to be added, as it will never have 'add to CRM' applied.

2) It won't be able to tell the difference between the messages in the thread that have been added, and the messages that still need to be added.

This isn't a particularly elegant solution, but with regards to 1), there's a cumbersome yet workable solution. You can set a script to check for messages in the inbox using .getInboxThreads() to check something like:

 // if message might have been updated
    if (messageHasLabelAdded == true && messageIsInInbox == True) {
       //Iterate through again to index the new messages
 }

Having this run every few minutes should catch any new messages in the thread, but it relies heavily on your users 'Archiving' a message once they're done.

With 2) are you able to get/post metadata with your CRM? If so, you can always get the messages ID using getId(). This is a unique property, so if it can be associated with the message in your CRM, it's just a question of comparing the ID with the IDs in your CRM and checking if a message with that ID is already uploaded.

That could get cubersome once you have several thousand messages uploaded to your CRM, but it might be the start you need.

How to use labels in Gmail to identify single messages instead of threads that have already been processed by a script

2 Answers