API.AI flow of logic - dialogflow-es

Question

This discussion applies to any integration, but as an example I'll talk about Messenger. Also, to give context, my backend is written in Java.
From what I've read, for custom scenarios (e.g. Account Linking), we shouldn't use API.AI directly. Instead, the "Callback URL" in Messenger settings (developer.facebook.com) should point to our own hosted app, which in turn calls api.api.ai/v1/query. Is that correct?
Secondly, my Intent in API.AI already has Use webhook ticked. I assume the flow of logic would be as follows:
Messenger → my app (webhook for Messenger) → api.ai → my app (webhook for api.ai)
Apparently it's not the case—API.AI never calls the webhook.
This is the JSON I sent to API.AI:
{"query":"hey","originalRequest":{"source":"facebook","data":{"object":"page","entry":[{"id":"xxx","time":yyy,"messaging":[{"sender":{"id":"zzz"},"recipient":{"id":"xxx"},"timestamp":yyy,"message":{"mid":"aaa","seq":bbb,"text":"hey"}}]}]}},"v":"20170704","sessionId":"1","lang":"en"}
And this is the response from API.AI:
{
"id": "xxx",
"timestamp": "yyy",
"lang": "en",
"result": {
"source": "agent",
"resolvedQuery": "hey",
"speech": "",
"action": "",
"parameters": {
"greeting": "hey"
},
"metadata": {
"inputContexts": [],
"outputContexts": [],
"intentName": "greeting",
"intentId": "zzz",
"webhookUsed": "true",
"webhookForSlotFillingUsed": "false",
"contexts": []
},
"score": 1.0
},
"status": {
"code": 200,
"errorType": "success"
},
"sessionId": "1"
}
Does it mean that my app should call the webhook (which is the same app but different endpoint) itself?

Answer 1

Your logic of flow is not correct.
In your case, Facebook will never talk to your app directly. It will always sends the user input to api.ai first. api.ai will then try to find a match from all intents you have created.
This is important, if api.ai manages to find an intent, it will invoke the webhook you have configured. However, if api.ai fail to find a match from any of your intents, it invokes the fallback intents which will post the response back to Facebook. In this case, your app will not be invoked.
My suggestion to you is before start testing on Facebook, use the test tool (located in the top right) in api.ai to make sure your input can be filter by the correct intents and your app is able to recessive your input from api.ai.

Answer 2

You have to give your intent an action! In your response the action field is empty!
If you are using the integrations your flow is like this:
fb -> api.ai -> your service -> api.ai -> fb
Your custom scenario may use it like this (no use of the integrations, just pure text understanding):
fb -> your service -> api.ai -> your service -> fb
EDIT:
Since I've implemented account linking for myself, i wrote following middleware.
https://github.com/hhucn/dbas-fb-hook/blob/master/src/dbas_fb_hook/handler.clj
The flow is now: fb -> service -> api.ai -> fb because I just filter out the auth related stuff and forward the messages directly to api.ai (using the api.ai facebook integration) or my other auth service.
(PS. Microservices are the best)

Answer 3

When API.AI is used as NLU (that is, you call /query), it doesn't call the webhooks. So, it's either:
Messenger → my app (webhook for Messenger) → api.ai
or:
Messenger → api.ai → my app (webhook for api.ai)

Answer 4

It depends if you use api.ai url for code-less agent configuration.
In code-less agent,api.ai will host the facebook interaction end points for you.
[https://bots.api.ai/facebook/*][1].
In code-less agent , typical flow will be
Messenger -> api.ai server->api.ai nlp -> your webhook
(if intent is enabled for webhook fulfillment)
In your scenario
Messenger -> your api server ->api.ai nlp -> your webhook /end point
created for that intent.This is a significant disadvantage as Fulfillment of 1 specific intent might be split across multiple end points, api's.In your case, you might not have enable webhook fulfillment on your intent ,'Hey'

Answer 5

Ideally, FB messenger will not talk to your webhook for messenger service. The workflow should be FB messenger->api.ai->webhook (where your actual logic resides) & even if in case you use, my app (webhook for Messenger) then you shouldn't be needing api.ai in the first place. It is because before taking any action, you need to know what user is saying & that can be done by NLP only! Using my app (webhook for Messenger) will replace NLP directly.
Second thing, We can not see fulfillment in api.ai json response. If at any point in time webhook call fails, your default response from api.ai will be posted as a reply to user's query & fallback will be called when api.ai itself does not understand the context of what user wants to say. Entering default response will help you in debugging as well.