Facebook Messenger bot not sending messages in order

Question

I\'m playing around with building a simple Facebook Messenger chatbot and I\'m having trouble sending messages in sequence.

In the example above, it should

Answer 1

Implement the send request as a Promise and only send consequent messages once the previous one is resolved

const send = (userId, messageData)  => {

      return new Promise((resolve, reject) => {
        request
        (
            {
                url     : BASE_URL + "me/messages",
                qs      : { access_token : PAGE_ACCESS_TOKEN },
                method  : "POST",
                json    : 
                        {
                            recipient: { id : userId },
                            message: messageData,
                        }
            }, (error, response, body) => 
            {
                if (error) { console.log("Error sending message: " + response.error); return reject(response.error); }
                else if (response.body.error) { console.log('Response body Error: ' + response.body.error); return reject(response.body.error); }

                console.log("Message sent successfully to " + userId); 
                return resolve(response);
            }
        );    
    });
};

Answer 2

Based on the recursive solution proposed by @user3884594, I kind of make it work using this (I removed the error handling in order to simplify):

send_messages (["message 01", "message 02", "message 03"]);

function send_messages (which, i = 0)
{
    request({
        url: 'https://graph.facebook.com/v2.10/me/messages',
        qs: { access_token: FACEBOOK_ACCESS_TOKEN },
        method: 'POST',
        json: { recipient: { id: senderId }, message: { text: which [i] }
    }, (error, response, body) => 
    {
        // You need to put your error handling logic here
        if (i++ < which.length - 1)
            send_messages (which, i);
    });
}

Answer 3

You can try putting them inside a setTimeout function so each one goes after a certain period of time.

So replace this:

sendTextMessage(user, "Hello!");
sendTextMessage(user, "1");
sendTextMessage(user, "2");
sendTextMessage(user, "3");

With this:

sendTextMessage(user, "Hello!");              

// 1 second

setTimeout(function() {
    sendTextMessage(user, "1");
}, 1000)

// 2 seconds

setTimeout(function() {
    sendTextMessage(user, "2");
}, 2000)

// 3 seconds

setTimeout(function() {
    sendTextMessage(user, "3");
}, 3000)    

And they should go one after another. You could also embed the functions inside each other if need be.

Answer 4

I had exactly same problem, that solution worked for me:

function sendMessage(recipient, messages, accessToken, i) {


    axios.post(baseURL + 'v2.11/me/messages/?access_token=' + accessToken,
        Object.assign({}, {
            messaging_type: "RESPONSE",
            recipient: {
                id: recipient
            }
        }, messages[i]['payload']) )
        .then(response => {

            if(i < messages.length) sendMessage( recipient, messages, accessToken, i+1 );

            },
            error => {})
        .catch(error => {});

}
sendMessage(recipient, flow['messages'], flow['page']['accessToken'], 0);

That's my question: Sequential Message Sending Using Facebook Send-API

Answer 5

You can achieve QUEUING by promises.

function delay(time) {
  return new Promise(function(resolve, reject) {
    setTimeout(resolve, time);
  });
}

delay(2000).then(() => {
  console.log('hi');
  delay(2000).then(() => {
    console.log('hello');
    delay(2000).then(() => {
      console.log('welcome');
    })
  })
})

Answer 6

I submitted a bug report to Facebook about this because I was having the same problem. They acknowledged that it is indeed a bug and are working to fix it: https://developers.facebook.com/bugs/565416400306038