RSS

src/lib/cache.js

@@ -22,6 +22,10 @@ class InstaCache {
 		return this.cache.get(key).data
 	}
 
+	getTtl(key, factor = 1) {
+		return Math.max((Math.floor(Date.now() - this.cache.get(key).time) / factor), 0)
+	}
+
 	/**
 	 * @param {string} key
 	 * @param {any} data

src/lib/collectors.js

@@ -5,7 +5,7 @@ const InstaCache = require("./cache")
 const {User} = require("./structures")
 require("./testimports")(constants, request, extractSharedData, InstaCache, User)
 
-const cache = new InstaCache(600e3)
+const cache = new InstaCache(constants.resource_cache_time)
 
 function fetchUser(username) {
 	return cache.getOrFetch("user/"+username, () => {

src/lib/constants.js

@@ -1,9 +1,11 @@
 module.exports = {
 	image_cache_control: `public, max-age=${7*24*60*60}`,
+	resource_cache_time: 30*60*1000,
 
 	external: {
 		timeline_query_hash: "e769aa130647d2354c40ea6a439bfc08",
-		timeline_fetch_first: 12
+		timeline_fetch_first: 12,
+		username_regex: "[\\w.]+"
 	},
 
 	symbols: {

src/lib/structures/Timeline.js

@@ -1,8 +1,11 @@
+const RSS = require("rss")
 const constants = require("../constants")
+const config = require("../../../config")
 const TimelineImage = require("./TimelineImage")
 const collectors = require("../collectors")
 require("../testimports")(constants, TimelineImage)
 
+/** @param {any[]} edges */
 function transformEdges(edges) {
 	return edges.map(e => new TimelineImage(e.node))
 }
@@ -13,6 +16,7 @@ class Timeline {
 	 */
 	constructor(user) {
 		this.user = user
+		/** @type {import("./TimelineImage")[][]} */
 		this.pages = []
 		this.addPage(this.user.data.edge_owner_to_timeline_media)
 		this.page_info = this.user.data.edge_owner_to_timeline_media.page_info
@@ -40,6 +44,23 @@ class Timeline {
 		this.pages.push(transformEdges(page.edges))
 		this.page_info = page.page_info
 	}
+
+	getFeed() {
+		const feed = new RSS({
+			title: `@${this.user.data.username}`,
+			feed_url: `${config.website_origin}/u/${this.user.data.username}/rss.xml`,
+			site_url: config.website_origin,
+			description: this.user.data.biography,
+			image_url: this.user.data.profile_pic_url,
+			pubDate: new Date(this.user.cachedAt),
+			ttl: this.user.getTtl(1000*60) // scale to minute
+		})
+		const page = this.pages[0] // only get posts from first page
+		for (const item of page) {
+			feed.item(item.getFeedData())
+		}
+		return feed
+	}
 }
 
 module.exports = Timeline

src/lib/structures/TimelineImage.js

@@ -1,9 +1,23 @@
+const config = require("../../../config")
+const {proxyImage} = require("../utils/proxyurl")
+const {compile} = require("pug")
+
+const rssDescriptionTemplate = compile(`
+img(alt=alt src=src)
+p(style='white-space: pre-line')= caption
+`)
+
 class GraphImage {
 	/**
 	 * @param {import("../types").GraphImage} data
 	 */
 	constructor(data) {
 		this.data = data
+		this.data.edge_media_to_caption.edges.forEach(edge => edge.node.text = edge.node.text.replace(/\u2063/g, "")) // I don't know why U+2063 INVISIBLE SEPARATOR is in here, but it is, and it causes rendering issues with certain fonts.
+	}
+
+	getProxy(url) {
+		return proxyImage(url)
 	}
 
 	/**
@@ -32,10 +46,34 @@ class GraphImage {
 		else return null
 	}
 
+	getIntroduction() {
+		const caption = this.getCaption()
+		if (caption) return caption.split("\n")[0].split(". ")[0] // try to get first meaningful line or sentence
+		else return null
+	}
+
 	getAlt() {
 		// For some reason, pages 2+ don't contain a11y data. Instagram web client falls back to image caption.
 		return this.data.accessibility_caption || this.getCaption() || "No image description available."
 	}
+
+	getFeedData() {
+		return {
+			title: this.getIntroduction() || "No caption provided",
+			description: rssDescriptionTemplate({src: this.data.display_url, alt: this.getAlt(), caption: this.getCaption()}),
+			author: this.data.owner.username,
+			url: `${config.website_origin}/p/${this.data.shortcode}`,
+			guid: `${config.website_origin}/p/${this.data.shortcode}`,
+			date: new Date(this.data.taken_at_timestamp*1000)
+			/*
+				Readers should display the description as HTML rather than using the media enclosure.
+				enclosure: {
+					url: this.data.display_url,
+					type: "image/jpeg" //TODO: can instagram have PNGs? everything is JPEG according to https://medium.com/@autolike.it/how-to-avoid-low-res-thumbnails-on-instagram-android-problem-bc24f0ed1c7d
+				}
+			*/
+		}
+	}
 }
 
 module.exports = GraphImage

src/lib/structures/User.js

@@ -1,5 +1,7 @@
+const constants = require("../constants")
+const {proxyImage} = require("../utils/proxyurl")
 const Timeline = require("./Timeline")
-require("../testimports")(Timeline)
+require("../testimports")(constants, Timeline)
 
 class User {
 	/**
@@ -11,6 +13,14 @@ class User {
 		this.followedBy = data.edge_followed_by.count
 		this.posts = data.edge_owner_to_timeline_media.count
 		this.timeline = new Timeline(this)
+		this.cachedAt = Date.now()
+		this.proxyProfilePicture = proxyImage(this.data.profile_pic_url)
+	}
+
+	getTtl(scale = 1) {
+		const expiresAt = this.cachedAt + constants.resource_cache_time
+		const ttl = expiresAt - Date.now()
+		return Math.ceil(Math.max(ttl, 0) / scale)
 	}
 
 	export() {

src/lib/utils/proxyurl.js

@@ -0,0 +1,7 @@
+function proxyImage(url) {
+	const params = new URLSearchParams()
+	params.set("url", url)
+	return "/imageproxy?"+params.toString()
+}
+
+module.exports.proxyImage = proxyImage