Mes: noviembre 2017

Some weeks ago, Google opened the possibility of create Gmail add-ons for all developers. Let’s see what are the possibilities and how to create and distribute our own Gmail add-on.

This is not a very hard and abstract post, add-ons are something easy, so I hope my explanation to be simple too. It is based on an add-on created by myself that allows any user adding an email to Google Tasks (probably it is more useful than the add-on for MSN Messenger that I created years ago which read received messages with «real» voice). It is a functionality that has been always present on Gmail web client but that is not available on mobile clients.

In order to create a Gmail add-on you need to create a new Google Apps Script project. After that you can add as much scripts as you want to create an interface using Cards and the functionality to interact with other services, APIs and so.

For instance, in our example the functionality is very basic:

function getContextualAddOn(e) {
  var message = getMessage(e);
  var subject = message.getSubject();
  var permaLink = message.getThread().getPermalink();
  
  var card = CardService.newCardBuilder();
  card.setHeader(CardService.newCardHeader()
                 .setTitle('Save as task'));
  var section = CardService.newCardSection();
  
  var button = prepareSend(permaLink);
  section.addWidget(button);
  
  section.addWidget(prepareList());
  
  section.addWidget(prepareTitle(subject));
  
  section.addWidget(prepareDueDate());
  
  section.addWidget(button);
  
  section.addWidget(prepareSign());
  
  card.addSection(section);
  console.log("Open");
  return [card.build()];
}

function getMessage(e){
  var accessToken = e.messageMetadata.accessToken;
  GmailApp.setCurrentMessageAccessToken(accessToken);
  
  var messageId = e.messageMetadata.messageId;
  return GmailApp.getMessageById(messageId);
}

function prepareSend(permaLink){
   var action = CardService.newAction()
  .setFunctionName("saveTask")
  .setParameters({permaLink: permaLink});
  return CardService.newTextButton()
                    .setText("Save")
                    .setOnClickAction(action);
}

function saveTask(e){
  var res = e['formInput'];
  var task = Tasks.newTask();
  task.title = res["title"];
  task.notes = e['parameters'].permaLink;
  
  if(res["due-date"] && res["due-date"] != "")
    task.due = res["due-date"] + "T00:00:00Z"
  
  task = Tasks.Tasks.insert(task, res["list"]);
  console.log("Saved");
}

function prepareList() {
  var response = Tasks.Tasklists.list();
  var taskLists = response.items;
  var dropdown = CardService.newSelectionInput()
     .setType(CardService.SelectionInputType.DROPDOWN)
     .setTitle("List")
     .setFieldName("list");

  if (taskLists && taskLists.length > 0) {
    Logger.log('Task lists:');
    for (var i = 0; i < taskLists.length; i++) {
      var taskList = taskLists[i];
      Logger.log('%s (%s)', taskList.title, taskList.id);
      dropdown.addItem(taskList.title, taskList.id, i==0);
    }
  } else {
    Logger.log('No task lists found.');
  }
  return dropdown;
}

function prepareTitle(subject){
  return CardService.newTextInput()
                    .setFieldName("title")
                    .setTitle("Title")
                    .setValue(subject)
}

function prepareDueDate(){
  var d = new Date();
  var dd = new Date(d.setDate(d.getDate() + ( 7 - d.getDay()) % 7));
  return CardService.newTextInput()
                    .setFieldName("due-date")
                    .setTitle("Due date")
                    .setValue(dd.getYear() + "-" + (dd.getMonth() + 1) + "-" + dd.getDate())
                    .setHint("YYYY-MM-DD");
}

function prepareSign(){
  var button = CardService.newTextButton()
     .setText("@JaviLopezG")
     .setOpenLink(CardService.newOpenLink()
         .setUrl("https://javilopezg.com/")
         .setOpenAs(CardService.OpenAs.OVERLAY)
         .setOnClose(CardService.OnClose.RELOAD_ADD_ON));
  return CardService.newKeyValue()
     .setContent("Developed and maintained by")
  .setButton(button);
}

You also have to change script’s manifest. To do this you need to access to the menu «View>Show manifest file». Now you can modify it as you want, following our example you have to replace the content with following lines:

{
  "timeZone": "GMT",
  "dependencies": {
    "enabledAdvancedServices": [{
      "userSymbol": "Tasks",
      "serviceId": "tasks",
      "version": "v1"
    }]
  },
  "oauthScopes": ["https://www.googleapis.com/auth/gmail.addons.execute", "https://www.googleapis.com/auth/gmail.addons.current.message.readonly", "https://www.googleapis.com/auth/tasks"],
  "gmail": {
    "name": "Save as task",
    "logoUrl": "https://i0.wp.com/javilopezg.com/wp-content/uploads/2017/11/save-as-tag-ico-24.png",
    "contextualTriggers": [{
      "unconditional": {
      },
      "onTriggerFunction": "getContextualAddOn"
    }],
    "primaryColor": "#000000",
    "secondaryColor": "#888888",
    "version": "TRUSTED_TESTER_V2",
    "openLinkUrlPrefixes": [
      "https://javilopezg.com/"
    ]
  }
}

As soon as you save all changes you are ready to publish your add-on. Unfortunately the Gmail add-ons store is not publicly available yet. However, you can get the ID of your add-on and distribute it to your company co-workers in order to allow them install your add on in their gmail accounts. See images below:

I know that it’s frustrating not being able to publish an add-on to all gmail users around the world yet. Anyway, I already have two cool ideas to implement as soon as I was able to distribute it at least to my friends. Something to draw an ordered tree of a conversation thread and an add-on to respond an e-mail with a video in an easy way. And you? What ideas are coming to your head?