Gmail插件文本输入的自动完成功能不起作用

Question

我正在尝试利用Google的gmail插件文本输入建议： https://developers.google.com/gsuite/add-ons/how-tos/suggestions

目标是当用户在输入框中输入文本时，会从用户的google驱动器files：list方法返回建议。

但是，似乎系统从未进入DriveApp.searchFiles行，并且没有错误报告。这就是我在日志中看到的全部内容：

  

[19-03-22 10：36：28：243 CET]文本输入：asdf

function getInsertImageComposeUI(e) {
  return [buildInitialMailMergeCard()];
}

function refreshSpreadsheetSuggestions(e){
  var suggestions = CardService.newSuggestions();

  var textInput = e.formInputs.spreadsheetInput[0];
  Logger.log("Text input: " + textInput);

  var files = DriveApp.searchFiles({'title': textInput});
  Logger.log("files: " + files);

  while(files.hasNext()){
    var file = files.next();
    suggestions.addSuggestion(file.getName());
  }

  return CardService.newSuggestionsResponseBuilder()
      .setSuggestions(suggestions)
      .build();
}

function buildInitialMailMergeCard() {

  var spreadsheetPickerChanged = CardService.newAction()
  .setFunctionName('refreshSpreadsheetSuggestions')
  .setParameters({"numSuggestions": "5"});

  var spreadsheetPicker = CardService.newTextInput()
    .setFieldName('spreadsheetInput')
    .setTitle('Choose a spreadsheet')
    .setSuggestionsAction(spreadsheetPickerChanged)

  var drivePickerSection = CardService.newCardSection().setHeader('Choose a Spreadsheet:');
  drivePickerSection.addWidget(spreadsheetPicker);

  var initialCard = CardService.newCardBuilder();
  initialCard.addSection(drivePickerSection);
  return initialCard.build();
}