From 23180c7db00bf39f96cf867ac1ac44c3a946bfc7 Mon Sep 17 00:00:00 2001
From: Ryan Barrett <git@ryanb.org>
Date: Tue, 15 Aug 2017 07:42:29 -0700
Subject: [PATCH] add /wm/... URL proxy that injects our webmention endpoint

---
 add_webmention.py           | 41 +++++++++++++++++++++++++++++++++++++
 app.yaml                    | 13 +++++++-----
 test/test_add_webmention.py | 32 +++++++++++++++++++++++++++++
 webmention.py               |  1 +
 4 files changed, 82 insertions(+), 5 deletions(-)
 create mode 100644 add_webmention.py
 create mode 100644 test/test_add_webmention.py

diff --git a/add_webmention.py b/add_webmention.py
new file mode 100644
index 0000000..552e5c4
--- /dev/null
+++ b/add_webmention.py
@@ -0,0 +1,41 @@
+"""HTTP proxy that injects our webmention endpoint.
+"""
+import logging
+
+import appengine_config
+
+import requests
+import webapp2
+
+import common
+
+LINK_HEADER = '<%s/webmention>; rel="webmention"'
+
+
+class AddWebmentionHandler(webapp2.RequestHandler):
+    """Proxies HTTP requests and adds Link header to our webmention endpoint."""
+
+    def get(self, url):
+        if not url.startswith('http://') and not url.startswith('https://'):
+            self.abort(400, 'URL must start with http:// or https://')
+
+        try:
+            resp = common.requests_get(url)
+        except requests.exceptions.Timeout as e:
+            logging.info('Returning 504 due to', exc_info=True)
+            self.abort(504, unicode(e))
+        except requests.exceptions.RequestException as e:
+            logging.info('Returning 502 due to', exc_info=True)
+            self.abort(502, unicode(e))
+
+        self.response.status_int = resp.status_code
+        self.response.write(resp.content)
+
+        self.response.headers.clear()
+        self.response.headers.update(resp.headers)
+        self.response.headers.add('Link', LINK_HEADER % self.request.host_url)
+
+
+app = webapp2.WSGIApplication([
+    ('/wm/(.+)', AddWebmentionHandler),
+], debug=appengine_config.DEBUG)
diff --git a/app.yaml b/app.yaml
index 906b55c..d3ec14d 100644
--- a/app.yaml
+++ b/app.yaml
@@ -35,14 +35,17 @@ handlers:
   upload: static/index.html
 
 # dynamic
-- url: /[^/]+/?(inbox)?
-  script: activitypub.app
-  # TODO
-  # secure: always
+- url: /wm/.+
+  script: add_webmention.app
+  secure: always
 
 - url: /webmention
   script: webmention.app
-  # secure: always
+  secure: always
+
+- url: /[^/]+/?(inbox)?
+  script: activitypub.app
+  secure: always
 
 skip_files:
 - ^(.*/)?.*\.py[co]
diff --git a/test/test_add_webmention.py b/test/test_add_webmention.py
new file mode 100644
index 0000000..3c342be
--- /dev/null
+++ b/test/test_add_webmention.py
@@ -0,0 +1,32 @@
+# coding=utf-8
+"""Unit tests for add_webmention.py.
+"""
+import unittest
+
+import mock
+import requests
+
+from add_webmention import app
+
+
+@mock.patch('requests.get')
+class AddWebmentionTest(unittest.TestCase):
+
+    def setUp(self):
+        self.resp = requests.Response()
+        self.resp._content = 'asdf ☕ qwert'
+        self.resp.headers = {
+            'Link': 'first',
+            'Foo': 'bar',
+        }
+
+    def test_get(self, mock_get):
+        self.resp.status_code = 202
+        mock_get.return_value = self.resp
+
+        got = app.get_response('/wm/http://url')
+        self.assertEqual(202, got.status_int)
+        self.assertEqual(self.resp._content, got.body)
+        self.assertEqual(['bar'], got.headers.getall('Foo'))
+        self.assertEqual(['first', '<http://localhost/webmention>; rel="webmention"'],
+                         got.headers.getall('Link'))
diff --git a/webmention.py b/webmention.py
index 6a7021f..8e67fa9 100644
--- a/webmention.py
+++ b/webmention.py
@@ -10,6 +10,7 @@ from granary import microformats2
 import mf2py
 import mf2util
 from oauth_dropins.webutil import util
+import requests
 import webapp2
 
 import activitypub