bot.handleFacebookMessage is not a function

[shubhadit]

I need to use the handleFacebookMessage function mentioned in the documentation, however, it doesn't seem to exist.

[mraaroncruz]

what version of bootbot are you using? it was added to v1.0.14 I believe. Check your package.json or yarn.lock.

[shubhadit]

Yes, I'm using v1.0.14
I see handleFacebookData in the codebase, but no function called handleFacebookMessage, which is what I needed.

[mraaroncruz]

do you have a bot instance?

const BootBot = require('bootbot');

const bot = new BootBot({
  accessToken: 'FB_ACCESS_TOKEN',
  verifyToken: 'FB_VERIFY_TOKEN',
  appSecret: 'FB_APP_SECRET'
});

bot.handleFacebookMessage(someMessage);

[shubhadit]

Yes. I do have a bot instance. I don't think the handleFacebookMessage is defined on the bot.

If you look at this commit: 863c5c3#diff-04c6e90faac2675aa89e2176d2eec7d8

The part added in the documentation shows the usage of handleFacebookMessage.
However, the function actually added in this commit is handleFacebookData and not handleFacebookMessage.

My requirement as highlighted in the documentation is to use handleFacebookMessage

[mraaroncruz]

I wrote the docs and the code months apart. I must have made a mistake in the docs which made it through code review. Sorry about that.

I will update the docs. Please use handleFacebookData.

[mraaroncruz]

The docs are updated @shubhadit. Thanks for the heads up and finding the source.
#95

[shubhadit]

There's an issue even in the current documentation/functioning. It will give an error when executing.
handleFacebookData expects the input to be an array however, we are passing it a single message.

The documentation should be as follows given the current implementation of handleFacebookData.

const linuxNewsBot   = new BootBot({argz});
const appleNewsBot   = new BootBot({argz});
const windowsNewsBot = new BootBot({argz});

myNonExpressRouter.get("/mywebhook", (data) => {
	**xyzBot**.handleFacebookData(data);
});

The handleFacebookData function works on the direct raw input from the webhook.
Internally handleFacebookData is iterating over the entries and messages as you can see below.

handleFacebookData(data) {
    // Iterate over each entry. There may be multiple if batched.
    data.entry.forEach((entry) => {
      // Iterate over each messaging event
      entry.messaging.forEach((event) => {
        //...
      });
  });
}

This causes two problems:

1. You don't know which page the message is coming
2. Since we don't know which page the message is coming from we don't know which bot to call handleFacebookData on
3. This implementation makes it difficult for us to use this for multiple pages

The perfect implementation would be to have a handleFacebookMessage function as earlier shown in the documentation as that removes the ambiguity of which page the message is coming from and allows us to have multiple pages & bots which we can use.

Can we add an implemenation for handleFacebookMessage as the earlier documentation was suggesting? I believe that will be more useful for people which the library via this method.

[mraaroncruz]

I will make a note to write better docs for the method.

To your issues (this will answer all three):

You do know which bot the message is for. This is the data you will receive on your webhook. From https://developers.facebook.com/docs/messenger-platform/webhook

{
  "object":"page",
  "entry":[
    {
      "id":"<PAGE_ID>", // <- This is your bot ID
      "time":1458692752478,
      "messaging":[
        {
          "sender":{
            "id":"<PSID>"
          },
          "recipient":{
            "id":"<PAGE_ID>" // I don't know what this is. Maybe it's useless (I hope)
          },

          ...
        }
      ]
    }
  ]
}

The assumption that I made when I pulled handleFacebookData() out was that entry.id was the page id (or bot id in your case). This would mean that you would be able to route using that before you sent entry into the handleFacebookData() method.
But from looking at this data, that might not be true since messaging also has a PAGE_ID. Do you have any insight here @shubhadit because the docs sure don't?

[mraaroncruz]

Nevermind, the docs aren't vague, they're contradictory.

Here it says that entry.id is thePAGE_ID so where you'd route your bot.
https://developers.facebook.com/docs/messenger-platform/webhook

But it also says that entry.messaging.recipient.id is the Recipient user ID

But here https://developers.facebook.com/docs/messenger-platform/reference/webhook-events/messages it says that recipient.id (same thing as above but zoomed in) is Your Page ID.

So I'm gonna say that you can route via entry.id and the handleFacebookData() API doesn't need to change. I cannot conceive of a situation where the entry.id would say one page and that entry.messaging.recipient.id would be different. If you run into this, please report it and we can update the API.

Thanks again.

[shubhadit]

The problem is that the PAGE_ID is inside each entry and not at the top level of data(which handleFacebookData expects).
Assumption is that since the Facebook API is sending PAGE_ID with each entry there could be a possibility that multiple entries have different PAGE_IDs.
So, we'll have to iterate over all the data.entry objects, filter out the objects that correspond to each page.
And then pass the filtered data to handleFacebookData which will then again iterate over all the entries and events.
This approach seems a little messy.

const linuxNewsBot   = new BootBot({argz});
const appleNewsBot   = new BootBot({argz});
const windowsNewsBot = new BootBot({argz});

myNonExpressRouter.get("/mywebhook", (data) => {
	**xyzBot**.handleFacebookData(data);
});

I've added #96 which will should solve everything.

[mraaroncruz]

You're trying to do something different than what bot.handleFacebookData() is intended to do.
And I think you don't understand the example above the way I intended it (which is my fault).

If you want a bot to handle a message differently than another bot, they need to be entirely different bootbot instances.

The original example shows 3 of such instances created. Each of these bots has its own page token thus will reply correctly when you try to later do a chat.say("I'm a bot!"). This will choose the correct user that is scoped to the bot with the correct page token and deliver the message to the intended page.

What the example on handleFacebookData() does is sets up an arbitrary express endpoint that you will use for your incoming bot requests from facebook (the webhook you add in messenger admin). At that point, you can parse the entry.id and use a simple routing table (an object would work). ex:

const bots = {
  "123446": linuxNewsBot,
  "4555444": appleNewsBot
};

myNonExpressRouter.get("/mywebhook", (data) => {
  const botID = data.entry.id.toString();
  bots[botID].handleFacebookData(data);
});

I don't see the benefit of handleFacebookMessage() but we would need get some feedback from @Charca. Maybe more sugar would be nice. I don't think it's necessary though. And it would add even more to the public API which shouldn't be taken lightly.

[shubhadit]

The problem with this example is that data.entry is actually an array, hence PAGE_ID won't directly be accessible at the top level like I was saying before, we'll have iterate over it.
Each entry object that we iterate over has its own PAGE_ID. So the code which users handleFacebookData will probably look something like:

const bots = {
    "123446": linuxNewsBot,
    "4555444": appleNewsBot
};

myNonExpressRouter.get("/mywebhook", (data) => {
    var dataGroupedByPage = {};
    data.entry.forEach((entry) => {
        if(!dataGroupedByPage[entry.id.toString()]) {
            dataGroupedByPage[entry.id.toString()] = [entry];
        } else {
            dataGroupedByPage[entry.id.toString()].push(entry);
        }
    });
    data.entry.forEach((botID,entries) => {
        bots[botID].handleFacebookData(entries);
    });
});

It just seems much cleaner, simpler and useful to me if we have an implementation which just handles each message and not the entire data object. Basically, what the initial documentation depicted using handleFacebookMessage:

const bots = {
    "123446": linuxNewsBot,
    "4555444": appleNewsBot
};

myNonExpressRouter.get("/mywebhook", (data) => {
    data.entry.forEach((entry) => {
        entry.messaging.forEach((event) => {
            bots[entry.id.toString()].handleFacebookData(event);
        });
    });
});

[mraaroncruz]

Please see this comment again. #94 (comment)

There is a top level page id. Why would you need per message page ids? Why would facebook give you a top level page id, then give you different page ids in individual messages?

I really want to know the answer to this. And if the answer is anything other than "they wouldn't", I think your PR is a great idea because my design is flawed.