webmention: when checking for fed.brid.gy backlink, don't require / path

fixes #278

templates/followers.html

@@ -0,0 +1,17 @@
+{% extends "base.html" %}
+
+{% block title %}{{ domain }}'s followers - Bridgy Fed{% endblock %}
+
+{% block content %}
+
+<h2 class="row">
+  <a href="https://{{ domain }}/">🌐 {{ domain }}</a>
+</h2>
+<h3 class="row">
+  <a href="/user/{{ domain }}/followers">{{ followers }} follower{% if followers != '1' %}s{% endif %}</a>
+  <!-- | <a href="/user/{{ domain }}/following">{{ following }} following</a> -->
+</h3>
+
+{% include "responses.html" %}
+
+{% endblock %}

tests/test_webmention.py

@@ -366,6 +366,18 @@ class WebmentionTest(testutil.TestCase):
 
         mock_get.assert_has_calls((self.req('http://a/post'),))
 
+    def test_backlink_without_trailing_slash(self, mock_get, mock_post):
+        mock_get.return_value = requests_response(
+            self.reply_html.replace('<a href="http://localhost/"></a>',
+                                    '<a href="http://localhost"></a>'),
+            content_type=CONTENT_TYPE_HTML)
+
+        got = self.client.post('/webmention', data={
+            'source': 'http://a/post',
+            'target': 'https://fed.brid.gy/',
+        })
+        self.assertEqual(200, got.status_code)
+
     def test_activitypub_create_reply(self, mock_get, mock_post):
         mock_get.side_effect = self.activitypub_gets
         mock_post.return_value = requests_response('abc xyz', status=203)

webmention.py

@@ -54,9 +54,10 @@ class Webmention(View):
 
         # check for backlink to bridgy fed (for webmention spec and to confirm
         # source's intent to federate to mastodon)
-        if (request.host_url not in source_resp.text and
-            urllib.parse.quote(request.host_url, safe='') not in source_resp.text):
-            error("Couldn't find link to {request.host_url}")
+        host_url = request.host_url.rstrip('/')  # don't require / path
+        if (host_url not in source_resp.text and
+            urllib.parse.quote(host_url, safe='') not in source_resp.text):
+            error(f"Couldn't find link to {host_url}")
 
         # convert source page to ActivityStreams
         entry = mf2util.find_first_entry(self.source_mf2, ['h-entry'])