facebook.js

'use strict';

// See the Send API reference
// https://developers.facebook.com/docs/messenger-platform/send-api-reference
const request = require('request');
const Config = require('./const.js');



const fbMessage = (id, data) => {
    var body = JSON.stringify({
        recipient: { id },
        message: data,
    });

    if (data.attachment) {

        var body = JSON.stringify({
            recipient: { id },
            message: data.attachment,
        });

    }






    const qs = 'access_token=' + encodeURIComponent(Config.FB_PAGE_TOKEN);
    return fetch('https://graph.facebook.com/me/messages?' + qs, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body,
        })
        .then(rsp => rsp.json())
        .then(json => {
            if (json.error && json.error.message) {
                throw new Error(json.error.message);
            }
            return json;
        });
};



const fbReq = request.defaults({
    uri: 'https://graph.facebook.com/me/messages',
    method: 'POST',
    json: true,
    qs: {
        access_token: Config.FB_PAGE_TOKEN
    },
    headers: {
        'Content-Type': 'application/json'
    },
});

// const fbMessage = (recipientId, msg, cb) => {

//     console.log("=========================>", msg)
//     if (IsJsonString(msg)) {
//         const opts = {
//             form: {
//                 recipient: {
//                     id: recipientId,
//                 },
//                 message: msg,
//             },
//         };

//         fbReq(opts, (err, resp, data) => {
//             if (cb) {
//                 cb(err || data.error && data.error.message, data);
//             }
//         });

//     } else {
//         const opts = {
//             form: {
//                 recipient: {
//                     id: recipientId,
//                 },
//                 message: {
//                     text: msg,
//                 },
//             },
//         };

//         fbReq(opts, (err, resp, data) => {
//             if (cb) {
//                 cb(err || data.error && data.error.message, data);
//             }
//         });
//     }
// };


// See the Webhook reference
// https://developers.facebook.com/docs/messenger-platform/webhook-reference
const getFirstMessagingEntry = (body) => {
    const val = body.object === 'page' &&
        body.entry &&
        Array.isArray(body.entry) &&
        body.entry.length > 0 &&
        body.entry[0] &&
        body.entry[0].messaging &&
        Array.isArray(body.entry[0].messaging) &&
        body.entry[0].messaging.length > 0 &&
        body.entry[0].messaging[0];

    return val || null;
};


/* To check String is IsJsonString*/

function IsJsonString(str) {
    try {
        JSON.parse(str);
    } catch (e) {
        return false;
    }
    return true;
}


module.exports = {
    getFirstMessagingEntry: getFirstMessagingEntry,
    fbMessage: fbMessage,
    fbReq: fbReq
};