Whenever you receive a webhook call, Flow expects a 200 response code from your server. With each reply you can send back messages and information.
Example
{
"verifyToken": "59a755e5-2581-4307-393f-630ad4983adf",
"messages": [{
"fallback": "Hi there",
"responses": [{
"type": "text",
"payload": {
"text": "Hi there"
},
"delay": 0
}]
}]
}
When your webhook runs on Node.js it's best to use flow-js-templates to send back reply messages. Any other technology stack is possible as long as you send back JSON formatted data.
Send later
Flow expects a Webhook call to return a reply within seconds. This can cause problems whenever you need to do a long running process.
Certain business processes may however take considerably longer. For those cases Flow provides a mechanism that allows you to reply with messages at a later point in time.
To do this there is a reply URL being provided with each webhook call. Use this URL to make a HTTP POST request.
The JSON payload you send is the same as when replying directly. Do not forget to include the verifyToken with each request.
// Node.js example using request
const opts = {
method: 'POST',
uri: replyUrl,
body: {
verifyToken,
messages
},
json: true
}
request(opts)
Trigger events
Like sending messages you can also trigger events using Webhooks. It works the same as with sending messages except you specify which event to trigger
// Node.js example using request
const opts = {
method: 'POST',
uri: replyUrl,
body: {
verifyToken,
events: [{
name: 'MY_EVENT_NAME'
}]
},
json: true
}
request(opts)
Sending params
With each reply (or immediate response) you can also manipulate data that is used by the NLP engine. This is done by sending along params with a reply message.
The following example sends a reply that contains the params destination_city and departure_city.
const replyBody = {
verifyToken,
params: {
destination_city: [{
value: 'AMS'
}],
departure_city: [{
value: 'NYC'
}]
},
events: [{
name: 'WELCOME'
}]
}
const opts = {
method: 'POST',
uri: replyUrl,
body: replyBody,
json: true
}
request(opts)
