Gmail Add-Ons onTriggerFunction only ran once per email even if opening the email again

Question

We\'re building a Gmail Add-On however we wish to show a different card on depending on some business logic when the add-on\'s onTriggerFunction is called. This wor

Answer 1

There are a couple ways you can reload the UI of a card. Both of them have to happen in an ActionResponse.

The first is if you want to reload the current card as the result of some state change caused by a user action:

function buildCounterCard() {
  const card = CardService.newCardBuilder().setName('Counter');

  const count = CountApi.get(); // Or however you get this data

  const countWidget = CardService.newKeyValue().setTopLabel('Current Count').setContent(`${count}`);

  const incrementAction = CardService.newAction().setFunctionName('handleIncrement');
  const incrementButton = CardService.newTextButton().setText('Increment').setOnClickAction(incrementAction);

  const section = CardService.newCardSection().addWidget(countWidget).addWidget(incrementButton);

  card.addSection(section);

  return card.build();
}

function handleIncrement() {
  const actionResponse = CardService.newActionResponseBuilder();

  CountApi.update(); // Or however you update the data

  const nav = CardService.newNavigation().updateCard(buildCounterCard());
  actionResponse.setNavigation(nav);

  return actionResponse.build();
}

The only other way I've found so far is to update the previous card in the Navigation stack. Imagine the following scenario:

1. User fills out a form and clicks "Save"
2. Script posts the data to the API and on success pushes a "Success" card on to the stack.
3. User sees the "Success" card with a message letting them know the data was saved and a button to go "Back" or "Home".

The action handler for that button could look something like this:

function handleBackClick(event) {
  const actionResponse = CardService.newActionResponseBuilder();

  clearPreviousCardState() // Otherwise the user sees the same data they filled out previously when they go back to the form

  const nav = CardService.newNavigation()
    .popCard()
    .updateCard(buildPreviousCard(event))
    .popToRoot();
  actionResponse.setNavigation(nav);

  return actionResponse.build();
}

For whatever reason this works, but updating multiple cards by chaining navigation steps along with updateCard() does not.

Seems like these are the only options right now. I find it pretty crazy that there's a Linear Optimization Service, but not a way to reload the UI. A commenter mentioned ActionResponseBuilder.setStateChanged(true), which sounds like what we want based on the documentation, but in my experience, it does absolutely nothing.

Answer 2

Unfortunately there is no way at the moment (July 2019) to force the trigger to run every time the email is opened. You can use ActionResponseBuilder.setStateChanged(true) as a response to a button click to instruct Gmail to clear the cache, but it can't be sent along with a normal card response.