From ab39f741f3c5e583002bfd1a9ef780b1a0c63143 Mon Sep 17 00:00:00 2001
From: Niko <niko@nobigtech.es>
Date: Mon, 21 Feb 2022 23:54:59 +0100
Subject: [PATCH] Intercept AP Create.Note and check if contains #fedilovequiz
 to parse

* FediLove Quiz is a standar text-based (parsed) protocol wrapped inside the object "Note"
 that can create a Quiz inside FediLove instance so there can be an interaction between non-FediLove
 instances and FediLove instances.
* TODO: implement the response from this side, so it goes parsed as a regular response to the original "Note"
 but parsed so if the target instance is FediLove, it parses it as a quiz result and can be interpreted on any AP software
---
 api/src/activity/federation.js | 10 +++++
 api/src/api-utils.js           |  5 +++
 api/src/api/auth.js            |  4 +-
 api/src/api/me.js              | 76 ++++++++++++++++++++++++++++++++++
 api/src/auth.js                |  1 -
 api/src/db.js                  |  1 +
 api/src/random.js              | 14 +++++++
 api/src/utils.js               |  6 ---
 8 files changed, 108 insertions(+), 9 deletions(-)
 create mode 100644 api/src/random.js
 delete mode 100644 api/src/utils.js

diff --git a/api/src/activity/federation.js b/api/src/activity/federation.js
index daef13b..7301a5e 100644
--- a/api/src/activity/federation.js
+++ b/api/src/activity/federation.js
@@ -37,6 +37,16 @@ module.exports = {
 				return true
 			}
 		}
+		if (msg.activity.type === 'Create')
+		{
+			if (msg.object.type === 'Note') {
+				var content = utils.firstIfArray(msg.object.content)
+				if (api.me.isFediloveQuiz(content))
+					await api.me.quizCreate(content, msg.actor.id,
+						msg.recipient.id, msg.object.id)
+				return true
+			}
+		}
 		if (msg.activity.type === 'Delete')
 		{
 			if (msg.object.type === 'Note') {
diff --git a/api/src/api-utils.js b/api/src/api-utils.js
index 36d7611..927fabe 100644
--- a/api/src/api-utils.js
+++ b/api/src/api-utils.js
@@ -14,6 +14,11 @@ module.exports = {
 			return false
 		}
 	},
+	md5sum: (str, size) => {
+		size = size || 32
+		const hasher = crypto.createHmac('md5','FediLove')
+		return hasher.update(str).digest('hex').slice(0, size)
+	},
 	firstIfArray: (o) => {
 		if (o === undefined)
 			return null
diff --git a/api/src/api/auth.js b/api/src/api/auth.js
index 22357f7..9bb6a16 100644
--- a/api/src/api/auth.js
+++ b/api/src/api/auth.js
@@ -1,6 +1,6 @@
 const api = require('../api-utils.js')
 const pwd = require('../passwd.js')
-const utils = require('../utils.js')
+const random = require('../random.js')
 
 module.exports = {
 	login: {
@@ -16,7 +16,7 @@ module.exports = {
 			if (!pwd.comparePassword(req.body.password, user.password))
 				return res.status(403).json({ error: 'invalid_password' })
 
-			const session_id = utils.randomString(128)
+			const session_id = random.base64(128)
 			const session = await db.table.sessions().insertOne({
 				id_user:		user._id,
 				session:		session_id
diff --git a/api/src/api/me.js b/api/src/api/me.js
index 7eae5c3..e74d5aa 100644
--- a/api/src/api/me.js
+++ b/api/src/api/me.js
@@ -1,6 +1,82 @@
 const auth = require('../auth.js')
+const utils = require('../api-utils.js')
+const random = require('../random.js')
+
+function quizParse(html, check) {
+	check = check === undefined ? false : check
+	if (html === undefined || html === null)
+		return false
+	html = decodeURIComponent(html)
+	html = html.replaceAll('&gt;','>').replaceAll('&lt;','<')
+		.replaceAll('&quot;','"').replaceAll('&amp;','&')
+	html = html.replaceAll(/<br\s+?\/?>/g, '<br>')
+	html = html.replaceAll('</p>', '\n')
+	html = html.replaceAll('<br>', '\n')
+	html = html.replaceAll(/<[^<>]+?>/g, '')
+	if (!html.toLowerCase().includes('#fedilovequiz'))
+		return false
+	if (check)
+		return true
+	var it = {}
+	var sq = false
+	var items = []
+	html = html+'\n999: end'
+	const lines = html.split('\n')
+	for (var i in lines) {
+		var ln = lines[i].trim()
+		if (ln === '')
+			continue
+		if (ln.toLowerCase().includes('#fedilovequiz')) {
+			sq = true
+			continue
+		}
+		if (sq) {
+			if (ln.match(/^\d+\:.*$/)) {
+				if (it.question !== undefined)
+					items.push(it)
+				ln = ln.substr(ln.indexOf(':')+1)
+				it = { question: ln.trim(), options: [] }
+			} else {
+				ln = ln.replaceAll(/\s?\|\s?/g,'|')
+					.replaceAll(/\|+/g, '|')
+				if (!ln.includes('|'))
+					continue
+				ps = ln.split('|')
+				for (var j in ps)
+					ps[j] = ps[j].trim()
+				it.options = ps
+			}
+		}
+	}
+	return items
+}
+
+async function quizCreate(content, from, to, replyTo) {
+	var quiz = quizParse(content)
+	if (quiz === false)
+		return false
+	if (from === undefined || from === null)
+		return false
+	if (to === undefined || to === null)
+		return false
+	if (replyTo === undefined || replyTo === null)
+		return false
+	const payload = {
+		id: utils.md5sum(replyTo, 16).toUpperCase(),
+		replyTo, from, to, content: quiz,
+	}
+	await db.table.quizs().insertOne(payload)
+	return payload
+}
+
+function isFediloveQuiz(html) {
+	return quizParse(html, true) !== false
+}
 
 module.exports = {
+	quizParse,
+	quizCreate,
+	isFediloveQuiz,
 	pending_follows: {
 		get: [auth.enforceSession, async (req, res) => {
 			let follows
diff --git a/api/src/auth.js b/api/src/auth.js
index 9b1e314..3d20c8b 100644
--- a/api/src/auth.js
+++ b/api/src/auth.js
@@ -1,5 +1,4 @@
 const pwd = require('./passwd.js')
-const utils = require('./utils.js')
 
 module.exports = {
 	enforceSession: async (req, res, next) => {
diff --git a/api/src/db.js b/api/src/db.js
index c752f10..1afe9a7 100644
--- a/api/src/db.js
+++ b/api/src/db.js
@@ -21,6 +21,7 @@ module.exports = {
 		objects:		() => { return mdb.collection('objects') },
 		users:			() => { return mdb.collection('u__users') },
 		sessions:		() => { return mdb.collection('u__sessions') },
+		quizs:			() => { return mdb.collection('u__quizs') },
 	},
 	getAPObject: async (objID, checkType) => {
 		const object = await module.exports.table
diff --git a/api/src/random.js b/api/src/random.js
new file mode 100644
index 0000000..c3ea6a4
--- /dev/null
+++ b/api/src/random.js
@@ -0,0 +1,14 @@
+const Crypto = require('crypto')
+
+module.exports = {
+	base64: (size) => {
+		return Crypto.randomBytes(size)
+			.toString('base64').slice(0, size)
+	},
+	md5: (size) => {
+		size = size || 32
+		const rnd = module.exports.base64(32)
+		const hasher = Crypto.createHmac("md5", rnd.substr(16))
+		return hasher.update(rnd.substr(0,16)).digest("hex").slice(0, size)
+	},
+}
diff --git a/api/src/utils.js b/api/src/utils.js
deleted file mode 100644
index d7db5f1..0000000
--- a/api/src/utils.js
+++ /dev/null
@@ -1,6 +0,0 @@
-const Crypto = require('crypto')
-
-exports.randomString = (size) => {
-	return Crypto.randomBytes(size)
-		.toString('base64').slice(0, size)
-}