From f25806464b88e7c004f96c12215fa0b21789bd67 Mon Sep 17 00:00:00 2001
From: Eakampreet <eakam1007@gmail.com>
Date: Thu, 17 Nov 2022 12:35:48 -0500
Subject: [PATCH] Add function to check if given url is a feed url

Return url if a feed url is passed

Add tests for isFeedUrl function
---
 src/api/feed-discovery/src/middleware.js | 11 ++++++-
 src/api/feed-discovery/src/util.js       | 22 +++++++++++++
 src/api/feed-discovery/test/util.test.js | 39 ++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/src/api/feed-discovery/src/middleware.js b/src/api/feed-discovery/src/middleware.js
index 29188c23ae..e97865c9e9 100644
--- a/src/api/feed-discovery/src/middleware.js
+++ b/src/api/feed-discovery/src/middleware.js
@@ -1,6 +1,6 @@
 const { logger, createError } = require('@senecacdot/satellite');
 
-const { isTwitchUrl, toTwitchFeedUrl, getBlogBody, getFeedUrls } = require('./util');
+const { isTwitchUrl, toTwitchFeedUrl, isFeedUrl, getBlogBody, getFeedUrls } = require('./util');
 
 // A middleware to ensure we get an array
 module.exports.checkForArray = () => {
@@ -43,6 +43,15 @@ module.exports.discoverFeedUrls = () => {
             };
           }
 
+          if (await isFeedUrl(url)) {
+            return [
+              {
+                feedUrl: url,
+                type: 'blog',
+              },
+            ];
+          }
+
           // Otherwise, try to parse out the feed URL from the body of the page
           const body = await getBlogBody(url);
           if (!body) {
diff --git a/src/api/feed-discovery/src/util.js b/src/api/feed-discovery/src/util.js
index 55dd7b32b0..8c49b85b4f 100644
--- a/src/api/feed-discovery/src/util.js
+++ b/src/api/feed-discovery/src/util.js
@@ -20,6 +20,27 @@ const toTwitchFeedUrl = (twitchChannelUrl) => {
   throw new Error('not a Twitch URL');
 };
 
+const isFeedUrl = async (url) => {
+  try {
+    const { statusCode, headers } = await got(url);
+    const contentType = headers['content-type'];
+    const validContentTypes = [
+      'application/xml',
+      'application/rss+xml',
+      'application/atom+xml',
+      'application/x.atom+xml',
+      'application/x-atom+xml',
+      'application/json',
+      'application/json+oembed',
+      'application/xml+oembed',
+    ];
+
+    return statusCode === 200 && validContentTypes.some((ct) => contentType.includes(ct));
+  } catch (err) {
+    return false;
+  }
+};
+
 const getBlogBody = async (blogUrl) => {
   try {
     logger.debug({ blogUrl }, 'Getting blog body');
@@ -101,3 +122,4 @@ module.exports.getBlogBody = getBlogBody;
 module.exports.getFeedUrls = getFeedUrls;
 module.exports.isTwitchUrl = isTwitchUrl;
 module.exports.toTwitchFeedUrl = toTwitchFeedUrl;
+module.exports.isFeedUrl = isFeedUrl;
diff --git a/src/api/feed-discovery/test/util.test.js b/src/api/feed-discovery/test/util.test.js
index 321f5fb9ec..e0a72ed442 100644
--- a/src/api/feed-discovery/test/util.test.js
+++ b/src/api/feed-discovery/test/util.test.js
@@ -3,6 +3,7 @@ const nock = require('nock');
 const {
   isTwitchUrl,
   toTwitchFeedUrl,
+  isFeedUrl,
   getBlogBody,
   getFeedUrlType,
   getFeedUrls,
@@ -31,6 +32,44 @@ describe('util.js', () => {
     );
   });
 
+  test('isFeedUrl returns true for a feed url', () => {
+    const feedUrl = 'https://blog.com/feed/user/';
+
+    [
+      'application/xml',
+      'application/rss+xml',
+      'application/atom+xml',
+      'application/x.atom+xml',
+      'application/x-atom+xml',
+      'application/json',
+      'application/json+oembed',
+      'application/xml+oembed',
+    ].forEach(async (type) => {
+      nock(feedUrl).get('/').reply(200, undefined, { 'Content-Type': type });
+      expect(await isFeedUrl(feedUrl)).toBe(true);
+    });
+  });
+
+  test('isFeedUrl returns false when given URL returns a non 200 status', async () => {
+    const feedUrl = 'https://blog.com/feed/user/';
+    nock(feedUrl).get('/').reply(404, 'Not Found');
+
+    expect(await isFeedUrl(feedUrl)).toBe(false);
+  });
+
+  test('isFeedUrl returns false if given URL returns a non feed content type', async () => {
+    const feedUrl = 'https://blog.com/user/';
+    nock(feedUrl).get('/').reply(200, '<html></html>', { 'Content-Type': 'text/html' });
+
+    expect(await isFeedUrl(feedUrl)).toBe(false);
+  });
+
+  test('isFeedUrl returns false if given an invalid URL is given', async () => {
+    const feedUrl = 'Not a URL';
+
+    expect(await isFeedUrl(feedUrl)).toBe(false);
+  });
+
   test('getBlogBody returns the expected body for a given URL', async () => {
     const blogUrl = 'https://test321.blogspot.com/';
     const mockBlogUrlResponseBody = `