AP users: extract out Protocol.serve() method

#512

activitypub.py

@@ -133,6 +133,12 @@ class ActivityPub(Protocol):
 
         _error()
 
+    @classmethod
+    def serve(cls, obj):
+        """Serves an :class:`Object` as AS2."""
+        return (postprocess_as2(as2.from_as1(obj.as1)),
+                {'Content-Type': as2.CONTENT_TYPE})
+
     @classmethod
     def verify_signature(cls, activity):
         """Verifies the current request's HTTP Signature.

models.py

@@ -29,7 +29,8 @@ import common
 WWW_DOMAINS = frozenset((
     'www.jvt.me',
 ))
-# TODO: eventually load from Protocol subclasses' IDs instead?
+# TODO: eventually load from protocol.protocols instead, if/when we can get
+# around the circular import
 PROTOCOLS = ('activitypub', 'bluesky', 'ostatus', 'webmention', 'ui')
 # 2048 bits makes tests slow, so use 1024 for them
 KEY_BITS = 1024 if DEBUG else 2048

protocol.py

@@ -109,6 +109,25 @@ class Protocol(metaclass=ProtocolMeta):
         """
         raise NotImplementedError()
 
+    @classmethod
+    def serve(cls, obj):
+        """Returns this protocol's Flask response for a given :class:`Object`.
+
+        For example, an HTML string and `'text/html'` for :class:`Webmention`,
+        or a dict with AS2 JSON and `'application/activity+json'` for
+        :class:`ActivityPub.
+
+        To be implemented by subclasses.
+
+        Args:
+          obj: :class:`Object`
+
+        Returns:
+          (response body, dict with HTTP headers) tuple appropriate to be
+          returned from a Flask handler
+        """
+        raise NotImplementedError()
+
     @classmethod
     def receive(cls, id, **props):
         """Handles an incoming activity.

redirect.py

@@ -21,7 +21,7 @@ from oauth_dropins.webutil import flask_util, util
 from oauth_dropins.webutil.flask_util import error
 from oauth_dropins.webutil.util import json_dumps, json_loads
 
-import activitypub
+from activitypub import ActivityPub
 from flask_app import app, cache
 from common import CACHE_TIME, CONTENT_TYPE_HTML
 from models import Object, User
@@ -92,7 +92,7 @@ def redir(to):
         obj = Webmention.load(to, check_backlink=False)
         if not obj or obj.deleted:
             return f'Object not found: {to}', 404
-        ret = activitypub.postprocess_as2(as2.from_as1(obj.as1))
+        ret, _ = ActivityPub.serve(obj)
         logger.info(f'Returning: {json_dumps(ret, indent=2)}')
         return ret, {
             'Content-Type': accept_type,

render.py

@@ -13,6 +13,7 @@ import activitypub
 from flask_app import app, cache
 import common
 from models import Object
+from webmention import Webmention
 
 logger = logging.getLogger(__name__)
 
@@ -42,23 +43,4 @@ def render():
     if obj.deleted or type == 'delete':
         return '', 410
 
-    # fill in author/actor if available
+    return Webmention.serve(obj)
-    obj_as1 = obj.as1
-    for field in 'author', 'actor':
-        val = as1.get_object(obj.as1, field)
-        if val.keys() == set(['id']) and val['id']:
-            # TODO: abstract on obj.source_protocol
-            loaded = activitypub.ActivityPub.load(val['id'])
-            if loaded and loaded.as1:
-                obj_as1 = {**obj_as1, field: loaded.as1}
-
-    # add HTML meta redirect to source page. should trigger for end users in
-    # browsers but not for webmention receivers (hopefully).
-    html = microformats2.activities_to_html([obj_as1])
-    utf8 = '<meta charset="utf-8">'
-    url = util.get_url(obj_as1)
-    if url:
-        refresh = f'<meta http-equiv="refresh" content="0;url={url}">'
-        html = html.replace(utf8, utf8 + '\n' + refresh)
-
-    return html

tests/test_activitypub.py

@@ -5,6 +5,7 @@ import copy
 from datetime import datetime, timedelta
 from hashlib import sha256
 import logging
+from unittest import skip
 from unittest.mock import ANY, call, patch
 import urllib.parse
 
@@ -1413,6 +1414,12 @@ class ActivityPubUtilsTest(testutil.TestCase):
 
         mock_get.assert_has_calls([self.as2_req('http://the/id')])
 
+    @skip
+    def test_serve(self):
+        obj = Object(id='http://orig', as2=LIKE)
+        self.assertEqual((LIKE_WRAPPED, {'Content-Type': 'application/activity+json'}),
+                         ActivityPub.serve(obj))
+
     def test_postprocess_as2_idempotent(self):
         g.user = self.make_user('foo.com')
 

tests/test_render.py

@@ -74,8 +74,11 @@ class RenderTest(testutil.TestCase):
 
     def test_render_with_author(self):
         with self.request_context:
-            Object(id='abc', as2=as2.from_as1({**COMMENT, 'author': 'def'})).put()
+            Object(id='abc', as2=as2.from_as1({**COMMENT, 'author': 'def'}),
-            Object(id='def', as2=as2.from_as1(ACTOR)).put()
+                   source_protocol='activitypub').put()
+            Object(id='def', as2=as2.from_as1(ACTOR),
+                   source_protocol='activitypub').put()
+
         resp = self.client.get('/render?id=abc')
         self.assertEqual(200, resp.status_code)
         self.assert_multiline_equals(

tests/test_webmention.py

@@ -1452,3 +1452,20 @@ class WebmentionUtilTest(testutil.TestCase):
 
         self.assert_req(mock_get, 'https://user.com/post')
         mock_post.assert_not_called()
+
+    def test_serve(self, _, __):
+        obj = Object(id='http://orig', mf2=ACTOR_MF2)
+        html, headers = Webmention.serve(obj)
+        self.assert_multiline_equals("""\
+<!DOCTYPE html>
+<html>
+<head><meta charset="utf-8">
+<meta http-equiv="refresh" content="0;url=https://user.com/"></head>
+<body class="">
+  <span class="h-card">
+    <a class="p-name u-url" href="https://user.com/">Ms. ☕ Baz</a>
+  </span>
+</body>
+</html>
+""", html, ignore_blanks=True)
+        self.assertEqual({'Content-Type': 'text/html; charset=utf-8'}, headers)

tests/testutil.py

@@ -72,6 +72,12 @@ class FakeProtocol(protocol.Protocol):
 
         raise requests.HTTPError(response=util.Struct(status_code='410'))
 
+    @classmethod
+    def serve(cls, obj):
+        logger.info(f'FakeProtocol.load {obj.key.id()}')
+        return (f'FakeProtocol object {obj.key.id()}',
+                {'Accept': 'fake/protocol'})
+
 
 class TestCase(unittest.TestCase, testutil.Asserts):
     maxDiff = None

webmention.py

@@ -23,7 +23,7 @@ from flask_app import app
 import common
 from models import Follower, Object, Target, User
 import models
-from protocol import Protocol
+from protocol import Protocol, protocols
 
 logger = logging.getLogger(__name__)
 
@@ -125,6 +125,35 @@ class Webmention(Protocol):
         obj.mf2 = entry
         return obj
 
+    @classmethod
+    def serve(cls, obj):
+        """Serves an :class:`Object` as HTML."""
+        obj_as1 = obj.as1
+
+        from_proto = protocols.get(obj.source_protocol)
+        if from_proto:
+            # fill in author/actor if available
+            for field in 'author', 'actor':
+                val = as1.get_object(obj.as1, field)
+                if val.keys() == set(['id']) and val['id']:
+                    loaded = from_proto.load(val['id'])
+                    if loaded and loaded.as1:
+                        obj_as1 = {**obj_as1, field: loaded.as1}
+        else:
+            logger.debug(f'Not hydrating actor or author due to source_protocol {obj.source_protocol}')
+
+        html = microformats2.activities_to_html([obj_as1])
+
+        # add HTML meta redirect to source page. should trigger for end users in
+        # browsers but not for webmention receivers (hopefully).
+        url = util.get_url(obj_as1)
+        if url:
+            utf8 = '<meta charset="utf-8">'
+            refresh = f'<meta http-equiv="refresh" content="0;url={url}">'
+            html = html.replace(utf8, utf8 + '\n' + refresh)
+
+        return html, {'Content-Type': common.CONTENT_TYPE_HTML}
+
 
 @app.post('/webmention')
 def webmention_external():