Free alternative to Buffer based on Airtable and Webtask.io

BufferAirtable.js

const Twit = require('twit')
const T = new Twit({
	consumer_key:         'xxx',
	consumer_secret:      'xxx',
	access_token:         'xxx',
	access_token_secret:  'xxx',
})

const Airtable = require('airtable')

Airtable.configure({
	endpointUrl: 'https://api.airtable.com',
	apiKey: 'xxx'
})

let baseName = 'Scheduled'
let base = Airtable.base('xxx')

const request = require('request').defaults({ encoding: null })

const uploadTweetMedia = (url, callback) => {
	request.get(url, (error, response, body) => {
		if (error) return callback(err)

        let b64content = new Buffer(body).toString('base64')

		// first we must post the media to Twitter
		T.post('media/upload', { media_data: b64content }, (err, data, response) => {
			if (err) return callback(err)

			console.log('Media uploaded.')

			callback(null, data.media_id_string)
		})
	})
}

const postTweet = (text, mediaIdStr, callback) => {

	//var altText = "Small flowers in a planter on a sunny balcony, blossoming."
	//var meta_params = { media_id: mediaIdStr, alt_text: { text: altText } }

	//T.post('media/metadata/create', meta_params, function (err, data, response) {
		//console.log(err, data)
	  // now we can reference the media and post a tweet (media will attach to the tweet)
	if (mediaIdStr) {
		var params = { status: text, media_ids: mediaIdStr }	
	} else {
		var params = { status: text }
	}

	T.post('statuses/update', params, (err, data, response) => {
		
		if (err) return callback(err)
	
		console.log('Tweet posted.')

		callback()
	})
	//})

}


// Fetch all Tweets from Airtable
const getAllTweets = (callback) => {

	let final = []

	base('Scheduled').select({
		// Selecting the first 3 records in Grid view:
		maxRecords: 100,
		view: "Grid view"
	}).eachPage(function page(records, fetchNextPage) {
		// This function (`page`) will get called for each page of records.
		
		final = final.concat(records)

		fetchNextPage()

	}, function done(err) {

		console.log(final.length + ' tweets found.')

		callback(final)
		
		if (err) { console.error(err); return cb(err) }
	})
}

/**
* @param context {WebtaskContext}
*/
module.exports = (context, cb) => {

	const HOUR = 1000 * 60 * 60
	// 2019-01-29 format

	getAllTweets(records => {

		for (let tweet of records) {

			if (!tweet.get('Schedule') || tweet.get('Tweeted')) continue

			let now = new Date()
			let publishDate = new Date(tweet.get('Publish'))
			let publishDelay = (now - publishDate)
			
			console.log('Publish date: '+publishDate)
			console.log('Publish delay: '+publishDelay)

			let shouldPublish = Math.abs(publishDelay) < HOUR


			if (!shouldPublish) {
				console.log("Tweet isn't scheduled for now. Next.")
				continue
			}

			console.log("Tweet scheduled for now!")

			base('Scheduled').update(tweet.getId(), {
				"Tweeted":true
			}, (err, newTweet) => {
				if (err) return cb(err)

				console.log(newTweet.get('Media'))
				let text = newTweet.get('Text')

				if (newTweet.get('Media') && newTweet.get('Media').length) {
					
					let imageLink = newTweet.get('Media')[0].url

					uploadTweetMedia(imageLink, (err, mediaId) => {
						if (err) return cb(err)

						console.log('Successfully uploaded: '+mediaId)

						postTweet(text, mediaId, (err) => {
							if (err) return cb(err)

							cb(null, { status: 'success' })
						})

					})

				} else {
					
					postTweet(text, null, (err) => {
						if (err) return cb(err)

						cb(null, { status: 'success' })

					})

				}
			});


		}

		return cb(null, { status: 'success' })

	})

}