preview: Use a dataclass for the embed data.

This is significantly cleaner than passing around `Dict[str, Any]` all
of the time.

zerver/lib/markdown/__init__.py

@@ -64,6 +64,7 @@ from zerver.lib.timezone import common_timezones
 from zerver.lib.types import LinkifierDict
 from zerver.lib.url_encoding import encode_stream, hash_util_encode
 from zerver.lib.url_preview import preview as link_preview
+from zerver.lib.url_preview.types import UrlEmbedData, UrlOEmbedData
 from zerver.models import EmojiInfo, Message, Realm, linkifiers_for_realm
 
 ReturnT = TypeVar("ReturnT")
@@ -682,54 +683,44 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
             desc_div = SubElement(summary_div, "desc")
             desc_div.set("class", "message_inline_image_desc")
 
-    def add_oembed_data(self, root: Element, link: str, extracted_data: Dict[str, Any]) -> bool:
-        oembed_resource_type = extracted_data.get("type", "")
-        title = extracted_data.get("title")
-
-        if oembed_resource_type == "photo":
-            image = extracted_data.get("image")
-            if image:
-                self.add_a(
-                    root,
-                    image_url=image,
-                    link=link,
-                    title=title,
-                )
-                return True
-
-        elif oembed_resource_type == "video":
-            html = extracted_data["html"]
-            image = extracted_data["image"]
-            title = extracted_data.get("title")
-            description = extracted_data.get("description")
-            self.add_a(
-                root,
-                image_url=image,
-                link=link,
-                title=title,
-                desc=description,
-                class_attr="embed-video message_inline_image",
-                data_id=html,
-                already_thumbnailed=True,
-            )
-            return True
-
-        return False
-
-    def add_embed(self, root: Element, link: str, extracted_data: Dict[str, Any]) -> None:
-        oembed = extracted_data.get("oembed", False)
-        if oembed and self.add_oembed_data(root, link, extracted_data):
+    def add_oembed_data(self, root: Element, link: str, extracted_data: UrlOEmbedData) -> None:
+        if extracted_data.image is None:
+            # Don't add an embed if an image is not found
             return
 
-        img_link = extracted_data.get("image")
-        if not img_link:
+        if extracted_data.type == "photo":
+            self.add_a(
+                root,
+                image_url=extracted_data.image,
+                link=link,
+                title=extracted_data.title,
+            )
+
+        elif extracted_data.type == "video":
+            self.add_a(
+                root,
+                image_url=extracted_data.image,
+                link=link,
+                title=extracted_data.title,
+                desc=extracted_data.description,
+                class_attr="embed-video message_inline_image",
+                data_id=extracted_data.html,
+                already_thumbnailed=True,
+            )
+
+    def add_embed(self, root: Element, link: str, extracted_data: UrlEmbedData) -> None:
+        if isinstance(extracted_data, UrlOEmbedData):
+            self.add_oembed_data(root, link, extracted_data)
+            return
+
+        if extracted_data.image is None:
             # Don't add an embed if an image is not found
             return
 
         container = SubElement(root, "div")
         container.set("class", "message_embed")
 
-        img_link = get_camo_url(img_link)
+        img_link = get_camo_url(extracted_data.image)
         img = SubElement(container, "a")
         img.set("style", "background-image: url(" + css_escape(img_link) + ")")
         img.set("href", link)
@@ -738,19 +729,17 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
         data_container = SubElement(container, "div")
         data_container.set("class", "data-container")
 
-        title = extracted_data.get("title")
-        if title:
+        if extracted_data.title:
             title_elm = SubElement(data_container, "div")
             title_elm.set("class", "message_embed_title")
             a = SubElement(title_elm, "a")
             a.set("href", link)
-            a.set("title", title)
-            a.text = title
-        description = extracted_data.get("description")
-        if description:
+            a.set("title", extracted_data.title)
+            a.text = extracted_data.title
+        if extracted_data.description:
             description_elm = SubElement(data_container, "div")
             description_elm.set("class", "message_embed_description")
-            description_elm.text = description
+            description_elm.text = extracted_data.description
 
     def get_actual_image_url(self, url: str) -> str:
         # Add specific per-site cases to convert image-preview URLs to image URLs.
@@ -868,10 +857,9 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
             return None
         return match.group(2)
 
-    def youtube_title(self, extracted_data: Dict[str, Any]) -> Optional[str]:
-        title = extracted_data.get("title")
-        if title is not None:
-            return f"YouTube - {title}"
+    def youtube_title(self, extracted_data: UrlEmbedData) -> Optional[str]:
+        if extracted_data.title is not None:
+            return f"YouTube - {extracted_data.title}"
         return None
 
     def youtube_image(self, url: str) -> Optional[str]:
@@ -897,10 +885,9 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
             return None
         return match.group(5)
 
-    def vimeo_title(self, extracted_data: Dict[str, Any]) -> Optional[str]:
-        title = extracted_data.get("title")
-        if title is not None:
-            return f"Vimeo - {title}"
+    def vimeo_title(self, extracted_data: UrlEmbedData) -> Optional[str]:
+        if extracted_data.title is not None:
+            return f"Vimeo - {extracted_data.title}"
         return None
 
     def twitter_text(

zerver/lib/url_preview/oembed.py

@@ -1,13 +1,13 @@
 import json
-from typing import Any, Dict, Optional
+from typing import Optional
 
 import requests
 from pyoembed import PyOembedException, oEmbed
 
+from zerver.lib.url_preview.types import UrlEmbedData, UrlOEmbedData
 
-def get_oembed_data(
-    url: str, maxwidth: int = 640, maxheight: int = 480
-) -> Optional[Dict[str, Any]]:
+
+def get_oembed_data(url: str, maxwidth: int = 640, maxheight: int = 480) -> Optional[UrlEmbedData]:
     try:
         data = oEmbed(url, maxwidth=maxwidth, maxheight=maxheight)
     except (PyOembedException, json.decoder.JSONDecodeError, requests.exceptions.ConnectionError):
@@ -16,29 +16,27 @@ def get_oembed_data(
     oembed_resource_type = data.get("type", "")
     image = data.get("url", data.get("image"))
     thumbnail = data.get("thumbnail_url")
-    html = data.pop("html", "")
+    html = data.get("html", "")
     if oembed_resource_type == "photo" and image:
-        return dict(
-            oembed=True,
+        return UrlOEmbedData(
             image=image,
-            type=oembed_resource_type,
+            type="photo",
             title=data.get("title"),
             description=data.get("description"),
         )
 
     if oembed_resource_type == "video" and html and thumbnail:
-        return dict(
-            oembed=True,
+        return UrlOEmbedData(
             image=thumbnail,
-            type=oembed_resource_type,
+            type="video",
             html=strip_cdata(html),
             title=data.get("title"),
             description=data.get("description"),
         )
 
-    # Otherwise, start with just the embed type.
-    return dict(
-        type=oembed_resource_type,
+    # Otherwise, use the title/description from pyembed as the basis
+    # for our other parsers
+    return UrlEmbedData(
         title=data.get("title"),
         description=data.get("description"),
     )

zerver/lib/url_preview/parsers/base.py

@@ -1,5 +1,7 @@
 import cgi
-from typing import Any, Optional
+from typing import Optional
+
+from zerver.lib.url_preview.types import UrlEmbedData
 
 
 class BaseParser:
@@ -14,5 +16,5 @@ class BaseParser:
             charset = cgi.parse_header(content_type)[1].get("charset")
         self._soup = BeautifulSoup(html_source, "lxml", from_encoding=charset)
 
-    def extract_data(self) -> Any:
+    def extract_data(self) -> UrlEmbedData:
         raise NotImplementedError()

zerver/lib/url_preview/parsers/generic.py

@@ -1,18 +1,19 @@
-from typing import Dict, Optional
+from typing import Optional
 from urllib.parse import urlparse
 
 from bs4.element import Tag
 
 from zerver.lib.url_preview.parsers.base import BaseParser
+from zerver.lib.url_preview.types import UrlEmbedData
 
 
 class GenericParser(BaseParser):
-    def extract_data(self) -> Dict[str, Optional[str]]:
-        return {
-            "title": self._get_title(),
-            "description": self._get_description(),
-            "image": self._get_image(),
-        }
+    def extract_data(self) -> UrlEmbedData:
+        return UrlEmbedData(
+            title=self._get_title(),
+            description=self._get_description(),
+            image=self._get_image(),
+        )
 
     def _get_title(self) -> Optional[str]:
         soup = self._soup

zerver/lib/url_preview/parsers/open_graph.py

@@ -1,37 +1,33 @@
-from typing import Dict
 from urllib.parse import urlparse
 
+from zerver.lib.url_preview.types import UrlEmbedData
+
 from .base import BaseParser
 
 
 class OpenGraphParser(BaseParser):
-    allowed_og_properties = {
-        "og:title",
-        "og:description",
-        "og:image",
-    }
-
-    def extract_data(self) -> Dict[str, str]:
+    def extract_data(self) -> UrlEmbedData:
         meta = self._soup.findAll("meta")
-        result = {}
+
+        data = UrlEmbedData()
+
         for tag in meta:
             if not tag.has_attr("property"):
                 continue
-            if tag["property"] not in self.allowed_og_properties:
-                continue
-
-            og_property_name = tag["property"][len("og:") :]
             if not tag.has_attr("content"):
                 continue
 
-            if og_property_name == "image":
+            if tag["property"] == "og:title":
+                data.title = tag["content"]
+            elif tag["property"] == "og:description":
+                data.description = tag["content"]
+            elif tag["property"] == "og:image":
                 try:
                     # We use urlparse and not URLValidator because we
                     # need to support relative URLs.
                     urlparse(tag["content"])
                 except ValueError:
                     continue
+                data.image = tag["content"]
 
-            result[og_property_name] = tag["content"]
-
-        return result
+        return data

zerver/lib/url_preview/preview.py

@@ -1,5 +1,5 @@
 import re
-from typing import Any, Callable, Dict, Match, Optional
+from typing import Any, Callable, Match, Optional
 from urllib.parse import urljoin
 
 import magic
@@ -13,6 +13,7 @@ from zerver.lib.outgoing_http import OutgoingSession
 from zerver.lib.pysa import mark_sanitized
 from zerver.lib.url_preview.oembed import get_oembed_data
 from zerver.lib.url_preview.parsers import GenericParser, OpenGraphParser
+from zerver.lib.url_preview.types import UrlEmbedData, UrlOEmbedData
 
 # FIXME: Should we use a database cache or a memcached in production? What if
 # OpenGraph data is changed for a site?
@@ -87,41 +88,39 @@ def catch_network_errors(func: Callable[..., Any]) -> Callable[..., Any]:
 @cache_with_key(preview_url_cache_key, cache_name=CACHE_NAME, with_statsd_key="urlpreview_data")
 def get_link_embed_data(
     url: str, maxwidth: int = 640, maxheight: int = 480
-) -> Optional[Dict[str, Any]]:
+) -> Optional[UrlEmbedData]:
     if not is_link(url):
         return None
 
     if not valid_content_type(url):
         return None
 
-    # We are using two different mechanisms to get the embed data
-    # 1. Use oEmbed data, if found, for photo and video "type" sites
-    # 2. Otherwise, use a combination of Open Graph tags and Meta tags
-    data = get_oembed_data(url, maxwidth=maxwidth, maxheight=maxheight) or {}
-    if data.get("oembed"):
+    # The oembed data from pyoembed may be complete enough to return
+    # as-is; if so, we use it.  Otherwise, we use it as a _base_ for
+    # the other, less sophisticated techniques which we apply as
+    # successive fallbacks.
+    data = get_oembed_data(url, maxwidth=maxwidth, maxheight=maxheight)
+    if data is not None and isinstance(data, UrlOEmbedData):
         return data
 
     response = PreviewSession().get(mark_sanitized(url), stream=True)
-    if response.ok:
-        og_data = OpenGraphParser(
-            response.content, response.headers.get("Content-Type")
-        ).extract_data()
-        for key in ["title", "description", "image"]:
-            if not data.get(key) and og_data.get(key):
-                data[key] = og_data[key]
+    if not response.ok:
+        return None
 
-        generic_data = (
-            GenericParser(response.content, response.headers.get("Content-Type")).extract_data()
-            or {}
-        )
-        for key in ["title", "description", "image"]:
-            if not data.get(key) and generic_data.get(key):
-                data[key] = generic_data[key]
-    if "image" in data:
-        data["image"] = urljoin(response.url, data["image"])
+    if data is None:
+        data = UrlEmbedData()
+
+    for parser_class in (OpenGraphParser, GenericParser):
+        parser = parser_class(response.content, response.headers.get("Content-Type"))
+        data.merge(parser.extract_data())
+
+    if data.image:
+        data.image = urljoin(response.url, data.image)
     return data
 
 
 @get_cache_with_key(preview_url_cache_key, cache_name=CACHE_NAME)
-def link_embed_data_from_cache(url: str, maxwidth: int = 640, maxheight: int = 480) -> Any:
-    return
+def link_embed_data_from_cache(
+    url: str, maxwidth: int = 640, maxheight: int = 480
+) -> Optional[UrlEmbedData]:
+    return None

zerver/lib/url_preview/types.py

@@ -0,0 +1,27 @@
+from dataclasses import dataclass
+from typing import Optional
+
+from typing_extensions import Literal
+
+
+@dataclass
+class UrlEmbedData:
+    type: Optional[str] = None
+    html: Optional[str] = None
+    title: Optional[str] = None
+    description: Optional[str] = None
+    image: Optional[str] = None
+
+    def merge(self, other: "UrlEmbedData") -> None:
+        if self.title is None and other.title is not None:
+            self.title = other.title
+        if self.description is None and other.description is not None:
+            self.description = other.description
+        if self.image is None and other.image is not None:
+            self.image = other.image
+
+
+@dataclass
+class UrlOEmbedData(UrlEmbedData):
+    type: Literal["photo", "video"]
+    html: Optional[str] = None

zerver/tests/test_link_embed.py

@@ -18,6 +18,7 @@ from zerver.lib.test_helpers import mock_queue_publish
 from zerver.lib.url_preview.oembed import get_oembed_data, strip_cdata
 from zerver.lib.url_preview.parsers import GenericParser, OpenGraphParser
 from zerver.lib.url_preview.preview import get_link_embed_data, link_embed_data_from_cache
+from zerver.lib.url_preview.types import UrlEmbedData, UrlOEmbedData
 from zerver.models import Message, Realm, UserProfile
 from zerver.worker.queue_processors import FetchLinksEmbedData
 
@@ -77,10 +78,9 @@ class OembedTestCase(ZulipTestCase):
         )
 
         data = get_oembed_data(url)
-        self.assertIsInstance(data, dict)
-        self.assertIn("title", data)
-        assert data is not None  # allow mypy to infer data is indexable
-        self.assertEqual(data["title"], response_data["title"])
+        assert data is not None
+        self.assertIsInstance(data, UrlEmbedData)
+        self.assertEqual(data.title, response_data["title"])
 
     @responses.activate
     def test_photo_provider(self) -> None:
@@ -107,11 +107,9 @@ class OembedTestCase(ZulipTestCase):
         )
 
         data = get_oembed_data(url)
-        self.assertIsInstance(data, dict)
-        self.assertIn("title", data)
-        assert data is not None  # allow mypy to infer data is indexable
-        self.assertEqual(data["title"], response_data["title"])
-        self.assertTrue(data["oembed"])
+        assert data is not None
+        self.assertIsInstance(data, UrlOEmbedData)
+        self.assertEqual(data.title, response_data["title"])
 
     @responses.activate
     def test_video_provider(self) -> None:
@@ -136,10 +134,9 @@ class OembedTestCase(ZulipTestCase):
         )
 
         data = get_oembed_data(url)
-        self.assertIsInstance(data, dict)
-        self.assertIn("title", data)
-        assert data is not None  # allow mypy to infer data is indexable
-        self.assertEqual(data["title"], response_data["title"])
+        assert data is not None
+        self.assertIsInstance(data, UrlOEmbedData)
+        self.assertEqual(data.title, response_data["title"])
 
     @responses.activate
     def test_connect_error_request(self) -> None:
@@ -204,30 +201,8 @@ class OpenGraphParserTestCase(ZulipTestCase):
 
         parser = OpenGraphParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertIn("title", result)
-        self.assertEqual(result["title"], "The Rock")
-        self.assertEqual(result.get("description"), "The Rock film")
-
-    def test_page_with_evil_og_tags(self) -> None:
-        html = b"""<html>
-          <head>
-          <meta property="og:title" content="The Rock" />
-          <meta property="og:type" content="video.movie" />
-          <meta property="og:url" content="http://www.imdb.com/title/tt0117500/" />
-          <meta property="og:image" content="http://ia.media-imdb.com/images/rock.jpg" />
-          <meta property="og:description" content="The Rock film" />
-          <meta property="og:html" content="<script>alert(window.location)</script>" />
-          <meta property="og:oembed" content="True" />
-          </head>
-        </html>"""
-
-        parser = OpenGraphParser(html, "text/html; charset=UTF-8")
-        result = parser.extract_data()
-        self.assertIn("title", result)
-        self.assertEqual(result["title"], "The Rock")
-        self.assertEqual(result.get("description"), "The Rock film")
-        self.assertEqual(result.get("oembed"), None)
-        self.assertEqual(result.get("html"), None)
+        self.assertEqual(result.title, "The Rock")
+        self.assertEqual(result.description, "The Rock film")
 
     def test_charset_in_header(self) -> None:
         html = """<html>
@@ -239,7 +214,7 @@ class OpenGraphParserTestCase(ZulipTestCase):
         )
         parser = OpenGraphParser(html, "text/html; charset=Big5")
         result = parser.extract_data()
-        self.assertEqual(result["title"], "中文")
+        self.assertEqual(result.title, "中文")
 
     def test_charset_in_meta(self) -> None:
         html = """<html>
@@ -252,7 +227,7 @@ class OpenGraphParserTestCase(ZulipTestCase):
         )
         parser = OpenGraphParser(html, "text/html")
         result = parser.extract_data()
-        self.assertEqual(result["title"], "中文")
+        self.assertEqual(result.title, "中文")
 
 
 class GenericParserTestCase(ZulipTestCase):
@@ -268,8 +243,8 @@ class GenericParserTestCase(ZulipTestCase):
         """
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertEqual(result.get("title"), "Test title")
-        self.assertEqual(result.get("description"), "Description text")
+        self.assertEqual(result.title, "Test title")
+        self.assertEqual(result.description, "Description text")
 
     def test_extract_image(self) -> None:
         html = b"""
@@ -286,9 +261,9 @@ class GenericParserTestCase(ZulipTestCase):
         """
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertEqual(result.get("title"), "Main header")
-        self.assertEqual(result.get("description"), "Description text")
-        self.assertEqual(result.get("image"), "http://test.com/test.jpg")
+        self.assertEqual(result.title, "Main header")
+        self.assertEqual(result.description, "Description text")
+        self.assertEqual(result.image, "http://test.com/test.jpg")
 
     def test_extract_bad_image(self) -> None:
         html = b"""
@@ -305,9 +280,9 @@ class GenericParserTestCase(ZulipTestCase):
         """
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertEqual(result.get("title"), "Main header")
-        self.assertEqual(result.get("description"), "Description text")
-        self.assertIsNone(result.get("image"))
+        self.assertEqual(result.title, "Main header")
+        self.assertEqual(result.description, "Description text")
+        self.assertIsNone(result.image)
 
     def test_extract_description(self) -> None:
         html = b"""
@@ -323,7 +298,7 @@ class GenericParserTestCase(ZulipTestCase):
         """
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertEqual(result.get("description"), "Description text")
+        self.assertEqual(result.description, "Description text")
 
         html = b"""
           <html>
@@ -333,12 +308,12 @@ class GenericParserTestCase(ZulipTestCase):
         """
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertEqual(result.get("description"), "description 123")
+        self.assertEqual(result.description, "description 123")
 
         html = b"<html><body></body></html>"
         parser = GenericParser(html, "text/html; charset=UTF-8")
         result = parser.extract_data()
-        self.assertIsNone(result.get("description"))
+        self.assertIsNone(result.description)
 
 
 class PreviewTestCase(ZulipTestCase):
@@ -730,8 +705,9 @@ class PreviewTestCase(ZulipTestCase):
                 in info_logs.output[0]
             )
 
-        self.assertIn("title", cached_data)
-        self.assertNotIn("image", cached_data)
+        assert cached_data
+        self.assertIsNotNone(cached_data.title)
+        self.assertIsNone(cached_data.image)
         msg = Message.objects.select_related("sender").get(id=msg_id)
         self.assertEqual(
             ('<p><a href="http://test.org/foo.html">' "http://test.org/foo.html</a></p>"),
@@ -768,8 +744,9 @@ class PreviewTestCase(ZulipTestCase):
                 in info_logs.output[0]
             )
 
-        self.assertIn("title", cached_data)
-        self.assertNotIn("image", cached_data)
+        assert cached_data
+        self.assertIsNotNone(cached_data.title)
+        self.assertIsNone(cached_data.image)
         msg = Message.objects.select_related("sender").get(id=msg_id)
         self.assertEqual(
             ('<p><a href="http://test.org/foo.html">' "http://test.org/foo.html</a></p>"),
@@ -804,8 +781,9 @@ class PreviewTestCase(ZulipTestCase):
                 in info_logs.output[0]
             )
 
-        self.assertIn("title", cached_data)
-        self.assertNotIn("image", cached_data)
+        assert cached_data
+        self.assertIsNotNone(cached_data.title)
+        self.assertIsNone(cached_data.image)
         msg = Message.objects.select_related("sender").get(id=msg_id)
         self.assertEqual(
             ('<p><a href="http://test.org/foo.html">' "http://test.org/foo.html</a></p>"),
@@ -836,12 +814,11 @@ class PreviewTestCase(ZulipTestCase):
                 in info_logs.output[0]
             )
 
-        self.assertIn("title", data)
-        self.assertIn("image", data)
-
+        assert data is not None
         msg = Message.objects.select_related("sender").get(id=msg_id)
-        self.assertIn(data["title"], msg.rendered_content)
-        self.assertIn(re.sub(r"([^\w-])", r"\\\1", data["image"]), msg.rendered_content)
+        self.assertIn(data.title, msg.rendered_content)
+        assert data.image is not None
+        self.assertIn(re.sub(r"([^\w-])", r"\\\1", data.image), msg.rendered_content)
 
     @responses.activate
     @override_settings(INLINE_URL_EMBED_PREVIEW=True)
@@ -941,12 +918,11 @@ class PreviewTestCase(ZulipTestCase):
             "message_content": url,
         }
 
-        mocked_data = {
-            "html": f'<iframe src="{url}"></iframe>',
-            "oembed": True,
-            "type": "video",
-            "image": f"{url}/image.png",
-        }
+        mocked_data = UrlOEmbedData(
+            html=f'<iframe src="{url}"></iframe>',
+            type="video",
+            image=f"{url}/image.png",
+        )
         self.create_mock_response(url)
         with self.settings(TEST_SUITE=False, CACHES=TEST_CACHES):
             with self.assertLogs(level="INFO") as info_logs:
@@ -963,7 +939,7 @@ class PreviewTestCase(ZulipTestCase):
 
         self.assertEqual(data, mocked_data)
         msg.refresh_from_db()
-        self.assertIn('a data-id="{}"'.format(escape(mocked_data["html"])), msg.rendered_content)
+        self.assertIn('a data-id="{}"'.format(escape(mocked_data.html)), msg.rendered_content)
 
     @responses.activate
     @override_settings(INLINE_URL_EMBED_PREVIEW=True)
@@ -983,7 +959,9 @@ class PreviewTestCase(ZulipTestCase):
             "message_content": url,
         }
 
-        mocked_data = {"title": "Clearer Code at Scale - Static Types at Zulip and Dropbox"}
+        mocked_data = UrlEmbedData(
+            title="Clearer Code at Scale - Static Types at Zulip and Dropbox"
+        )
         self.create_mock_response(url)
         with self.settings(TEST_SUITE=False, CACHES=TEST_CACHES):
             with self.assertLogs(level="INFO") as info_logs:
@@ -1019,7 +997,9 @@ class PreviewTestCase(ZulipTestCase):
             "message_content": url,
         }
 
-        mocked_data = {"title": "Clearer Code at Scale - Static Types at Zulip and Dropbox"}
+        mocked_data = UrlEmbedData(
+            title="Clearer Code at Scale - Static Types at Zulip and Dropbox"
+        )
         self.create_mock_response(url)
         with self.settings(TEST_SUITE=False, CACHES=TEST_CACHES):
             with self.assertLogs(level="INFO") as info_logs: