Update Facebook cache with a sitemap file

index.js

//
// Update Facebook cache with a sitemap file
// Syntax: 
// 
// node index <sitemap URL> [delay between facebook API calls in ms]
// 
// example: 
// > node index https://example.com/sitemap_index.xml
//

"use strict";

const https = require("https");
const http = require("http");
const URL = require("url");

run(process.argv.reverse());

function run(args) {
	let fbRequestPause = 1000;
	let sitemapURL;
	if (!isNaN(args[0])) {
		fbRequestPause = Math.max(args[0], 500);
		sitemapURL = args[1];
	} else {
		sitemapURL = args[0];
	}
	if (/https?/.test(URL.parse(sitemapURL).protocol)) {
		getSitemapURLs(sitemapURL, [])
			.then(urls => updateFacebookCache(urls, fbRequestPause, 0))
			.then(() => console.log("finished!"))
			.catch(console.error);
	} else {
		console.error("Error: missing or invalid parameter (sitemap URL)");
	}
}

function getSitemapURLs(sitemapURL, urls) {
	return retrieveSitemapContent(sitemapURL)
		.then(sitemapContent => {
			const locURLs = sitemapContent
				.split(/<loc>(.*?)<\/loc>/)
				.filter((value, index) => index % 2);
			if (/^<sitemapindex/.test(sitemapContent) && /<\/sitemapindex>$/.test(sitemapContent)) {
				return Promise.all(locURLs.map(url => getSitemapURLs(url, urls)))
					.then(() => urls);
			} else {
				Array.prototype.splice.apply(urls, [0, 0].concat(locURLs));
				return urls;
			}
		});
}

function retrieveSitemapContent(sitemapURL) {
	return new Promise((resolve, reject) => {
		let content = "";
		const url = URL.parse(sitemapURL);
		const request = (url.protocol == "https" ? https : http).request({
			method: "GET",
			hostname: url.hostname,
			path: url.pathname,
		}, response => {
			response.on("data", data => content += data);
			response.on("end", () => resolve(content));
			response.on("error", reject);
		});
		request.end();
		request.on("error", reject);
	});
}

function updateFacebookCache(urls, fbRequestPause, index) {
	return new Promise((resolve, reject) => {
		const url = urls[index];
		if (url) {
			console.log(">", url);
			updateFacebookCacheURL(url)
				.then(() => setTimeout(updateFacebookCache, fbRequestPause, urls, fbRequestPause, index + 1))
				.catch(reject);
		} else {
			resolve();
		}
	});
}

function updateFacebookCacheURL(url) {
	return new Promise((resolve, reject) => {
		const postData = "id=" + encodeURI(url) + "&scrape=true";
		const request = https.request({
			method: "POST",
			hostname: "graph.facebook.com",
			path: "/",
			headers: {
				"Content-Type": "application/x-www-form-urlencoded",
				"Content-Length": Buffer.byteLength(postData)
			}
		}, response => {
			response.on("data", () => { });
			response.on("end", resolve);
			response.on("error", reject);
		});
		request.write(postData);
		request.end();
		request.on("error", reject);
	});
}