Add feed checking logic, set to run at 30 sec intervals

app/config.json

@@ -1,5 +1,6 @@
 {
 	"saveIntervalSec": 60,
+	"feedCheckIntervalSec": 30,
 	"commands": {
 		"version": "version",
 		"addFeed": "add-feed"

app/index.js

@@ -20,8 +20,13 @@ module.exports = (client) => {
 	const guildsData = FileSystem.existsSync(SAVE_FILE) ? fromJSON(JsonFile.readFileSync(SAVE_FILE)) : {};
 	setInterval(() => writeFile(guildsData), config.saveIntervalSec * 1000);
 
-	parseLinksInAllGuilds(client.guilds, guildsData).then(writeFile(guildsData));
+	parseLinksInGuilds(client.guilds, guildsData).then(writeFile(guildsData));
 
+	//set up an interval to check all the feeds
+	checkFeedsInGuilds(guildsData);
+	setInterval(() => checkFeedsInGuilds(guildsData), config.feedCheckIntervalSec * 1000);
+
+	//set up an on message handler to detect when links are posted
 	client.on("message", message => {
 		if (message.author.id !== client.user.id) { //check the bot isn't triggering itself
 			if (message.channel.type === "dm")
@@ -69,11 +74,14 @@ function addFeed(client, guildsData, message) {
 			}
 			else
 				responseMessage.reply("Your feed has not been saved, please add it again with the correct details");
-
 		});
 }
 
-function parseLinksInAllGuilds(guilds, guildsData) {
+function checkFeedsInGuilds(guildsData) {
+	guildsData.forEach(guild => guild.checkFeeds());
+}
+
+function parseLinksInGuilds(guilds, guildsData) {
 	const promises = [];
 	for (let guild of guilds) {
 		const guildData = guildsData[guild.id];

app/models/feed-data.js

@@ -1,3 +1,11 @@
+//my imports
+const DiscordUtil = require("discordjs-util");
+
+//external lib imports
+const Dns = require("dns");
+const Url = require("url");
+const FeedRead = require("feed-read");
+
 module.exports = class FeedData {
 	constructor({ link, channelName, roleName, cachedLinks }) {
 		this.link = link;
@@ -23,8 +31,46 @@ module.exports = class FeedData {
 				.catch(reject);
 		});
 	}
+
+	check(guild) {
+		Dns.resolve(Url.parse(this.link).host, err => { //check we can resolve the host, so we can throw an appropriate error if it fails
+			if (err)
+				DiscordUtil.dateError("Connection Error: Can't resolve host", err); //log our error if we can't resolve the host
+			else
+				FeedRead(this.link, (err, articles) => { //check the feed
+					if (err)
+						DiscordUtil.dateError(err);
+					else {
+						let latest = articles[0]; //extract the latest link
+						latest = normaliseUrl(latest); //standardise it a bit
+
+						//if we don't have it cached already, cache it and callback
+						if (!this.cachedLinks.includes(latest)) {
+							this.cachedLinks.push(latest);
+							post(guild, latest);
+						}
+					}
+				});
+		});
+	}
 };
 
+function post(guild, link){
+	const channel = guild.channels.first(ch => ch.type === "text" && ch.name.toLower() === this.channelName.toLower());
+	channel.send(link);
+}
+
+function normaliseUrl(url) {
+	url = url.replace("https://", "http://"); //cheaty way to get around http and https not matching
+
+	if (Url.parse(url).host.includes("youtu")) //detect youtu.be and youtube.com - yes I know it's hacky
+		url = url.split("&")[0]; //quick way to chop off stuff like &feature=youtube
+
+	url = url.replace("http://www.youtube.com/watch?v=", "http://youtu.be/"); //turn full url into share url
+
+	return url;
+}
+
 function getUrls(str) {
 	return str.match(/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig);
 }

app/models/guild-data.js

@@ -16,4 +16,8 @@ module.exports = class GuildData {
 
 		return Promise.all(promises);
 	}
+
+	checkFeeds() {
+		this.feeds.forEach(feed => feed.check());
+	}
 };