From 65ce8353dcd954e88dfa909a71196667253bb1c1 Mon Sep 17 00:00:00 2001
From: Jackson Harper <jacksonh@gmail.com>
Date: Wed, 2 Mar 2022 23:09:10 -0800
Subject: [PATCH] Attempt to pull URLs for probable newsletter emails out of
 content

---
 packages/api/src/routers/svc/emails.ts        |  4 ++--
 packages/api/src/utils/parser.ts              | 24 +++++++++++++++++++
 packages/api/src/utils/usernamePolicy.ts      |  1 +
 .../services/save_newsletter_email.test.ts    | 15 ------------
 packages/api/test/utils/parser.test.ts        | 23 ++++++++++++++----
 5 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/packages/api/src/routers/svc/emails.ts b/packages/api/src/routers/svc/emails.ts
index d1199f942..ce8f20e3e 100644
--- a/packages/api/src/routers/svc/emails.ts
+++ b/packages/api/src/routers/svc/emails.ts
@@ -4,7 +4,7 @@ import { sendEmail } from '../../utils/sendEmail'
 import { analytics } from '../../utils/analytics'
 import { getNewsletterEmail } from '../../services/newsletters'
 import { env } from '../../env'
-import { isProbablyNewsletter } from '../../utils/parser'
+import { findNewsletterUrl, isProbablyNewsletter } from '../../utils/parser'
 import { saveNewsletterEmail } from '../../services/save_newsletter_email'
 
 interface ForwardEmailMessage {
@@ -57,7 +57,7 @@ export function emailsServiceRouter() {
           title: data.subject,
           content: data.html,
           author: data.from,
-          url: 'https://omnivore.app/no_url',
+          url: (await findNewsletterUrl(data.html)) || 'https://omnivore.app/no_url',
         })
         res.status(200).send('Newsletter')
         return
diff --git a/packages/api/src/utils/parser.ts b/packages/api/src/utils/parser.ts
index 74f1565a9..964fea610 100644
--- a/packages/api/src/utils/parser.ts
+++ b/packages/api/src/utils/parser.ts
@@ -399,3 +399,27 @@ export const isProbablyNewsletter = (html: string): boolean => {
 
   return false
 }
+
+// Given an HTML blob tries to find a URL to use for
+// a canonical URL.
+export const findNewsletterUrl = async (html: string): Promise<string | undefined> => {
+  const dom = new JSDOM(html).window
+
+  // If there is an <h1 element with a URL, use that
+  const postLink = dom.document.querySelector('h1 a ')
+  if (postLink) {
+    const href = postLink.getAttribute('href')
+    if (href) {
+      // Try to make a HEAD request so we get the redirected URL, since these
+      // will usually be behind tracking url redirects
+      return axios({
+        method: 'HEAD',
+        url: href,
+      })
+      .then(res => res.request.res.responseUrl)
+      .catch((e) => href)
+    }
+  }
+
+  return undefined
+}
diff --git a/packages/api/src/utils/usernamePolicy.ts b/packages/api/src/utils/usernamePolicy.ts
index fa64c469e..20bd5fe32 100644
--- a/packages/api/src/utils/usernamePolicy.ts
+++ b/packages/api/src/utils/usernamePolicy.ts
@@ -94,6 +94,7 @@ const RESERVED_NAMES = new Set([
   'mine',
   'mis',
   'news',
+  'no_url',
   'oauth',
   'oauth_clients',
   'offers',
diff --git a/packages/api/test/services/save_newsletter_email.test.ts b/packages/api/test/services/save_newsletter_email.test.ts
index 8804329f7..bf29de3ac 100644
--- a/packages/api/test/services/save_newsletter_email.test.ts
+++ b/packages/api/test/services/save_newsletter_email.test.ts
@@ -3,15 +3,8 @@ import { expect } from 'chai'
 import 'chai/register-should'
 import {
   createTestUser,
-  createUserWithoutProfile,
   deleteTestUser,
-  getProfile,
 } from '../db'
-import { createGroup } from '../../src/services/create_group'
-import {
-  getUserFollowers,
-  getUserFollowing,
-} from '../../src/services/followers'
 import { createNewsletterEmail } from '../../src/services/newsletters'
 import { saveNewsletterEmail } from '../../src/services/save_newsletter_email'
 import { getRepository } from 'typeorm'
@@ -23,14 +16,6 @@ describe('saveNewsletterEmail', () => {
     await deleteTestUser(username)
   })
 
-  interface NewsletterMessage {
-    email: string
-    content: string
-    url: string
-    title: string
-    author: string
-  }
-
   it('adds the newsletter to the library', async () => {
     const user = await createTestUser(username)
     const email = await createNewsletterEmail(user.id)
diff --git a/packages/api/test/utils/parser.test.ts b/packages/api/test/utils/parser.test.ts
index 16d4bbca7..2a2fedcfb 100644
--- a/packages/api/test/utils/parser.test.ts
+++ b/packages/api/test/utils/parser.test.ts
@@ -3,12 +3,13 @@ import { expect } from 'chai'
 import 'chai/register-should'
 import { JSDOM } from 'jsdom'
 import fs from 'fs'
-import { isProbablyNewsletter } from '../../src/utils/parser'
+import { findNewsletterUrl, isProbablyNewsletter } from '../../src/utils/parser'
+
+const load = (path: string): string => {
+  return fs.readFileSync(path, 'utf8')
+}
 
 describe('isProbablyNewsletter', () => {
-  const load = (path: string): string => {
-    return fs.readFileSync(path, 'utf8')
-  }
   it('returns true for substack newsletter', () => {
     const html = load('./test/utils/data/substack-forwarded-newsletter.html')
     isProbablyNewsletter(html).should.be.true
@@ -18,3 +19,17 @@ describe('isProbablyNewsletter', () => {
     isProbablyNewsletter(html).should.be.false
   })
 })
+
+describe('findNewsletterUrl', async () => {
+  it('gets the URL from the header if it is a newsletter', async () => {
+    const html = load('./test/utils/data/substack-forwarded-newsletter.html')
+    const url = await findNewsletterUrl(html)
+    // Not sure if the redirects from substack expire, this test could eventually fail
+    expect(url).to.startWith('https://newsletter.slowchinese.net/p/companies-that-eat-people-217')
+  })
+  it('returns undefined if it is not a newsletter', async () => {
+    const html = load('./test/utils/data/substack-forwarded-welcome-email.html')
+    const url = await findNewsletterUrl(html)
+    expect(url).to.be.undefined
+  })
+})