Be more lenient in the oEmbed response parsing. (#14089)

Attempt to parse any valid information from an oEmbed response
(instead of bailing at the first unexpected data). This should allow
for more partial oEmbed data to be returned, resulting in better /
more URL previews, even if those URL previews are only partial.
This commit is contained in:
Patrick Cloke 2022-10-07 09:29:43 -04:00 committed by GitHub
parent 66a7857334
commit 00c93d2e7e
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3 changed files with 166 additions and 57 deletions

1
changelog.d/14089.bugfix Normal file
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@ -0,0 +1 @@
Fix a bug where invalid oEmbed fields would cause the entire response to be discarded. Introduced in Synapse 1.18.0.

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@ -139,65 +139,72 @@ class OEmbedProvider:
try:
# oEmbed responses *must* be UTF-8 according to the spec.
oembed = json_decoder.decode(raw_body.decode("utf-8"))
except ValueError:
return OEmbedResult({}, None, None)
# The version is a required string field, but not always provided,
# or sometimes provided as a float. Be lenient.
oembed_version = oembed.get("version", "1.0")
if oembed_version != "1.0" and oembed_version != 1:
raise RuntimeError(f"Invalid oEmbed version: {oembed_version}")
return OEmbedResult({}, None, None)
# Ensure the cache age is None or an int.
cache_age = oembed.get("cache_age")
if cache_age:
cache_age = int(cache_age) * 1000
# Attempt to parse the cache age, if possible.
try:
cache_age = int(oembed.get("cache_age")) * 1000
except (TypeError, ValueError):
# If the cache age cannot be parsed (e.g. wrong type or invalid
# string), ignore it.
cache_age = None
# The results.
open_graph_response = {
"og:url": url,
}
# The oEmbed response converted to Open Graph.
open_graph_response: JsonDict = {"og:url": url}
title = oembed.get("title")
if title:
if title and isinstance(title, str):
open_graph_response["og:title"] = title
author_name = oembed.get("author_name")
if not isinstance(author_name, str):
author_name = None
# Use the provider name and as the site.
provider_name = oembed.get("provider_name")
if provider_name:
if provider_name and isinstance(provider_name, str):
open_graph_response["og:site_name"] = provider_name
# If a thumbnail exists, use it. Note that dimensions will be calculated later.
if "thumbnail_url" in oembed:
open_graph_response["og:image"] = oembed["thumbnail_url"]
thumbnail_url = oembed.get("thumbnail_url")
if thumbnail_url and isinstance(thumbnail_url, str):
open_graph_response["og:image"] = thumbnail_url
# Process each type separately.
oembed_type = oembed["type"]
oembed_type = oembed.get("type")
if oembed_type == "rich":
calc_description_and_urls(open_graph_response, oembed["html"])
html = oembed.get("html")
if isinstance(html, str):
calc_description_and_urls(open_graph_response, html)
elif oembed_type == "photo":
# If this is a photo, use the full image, not the thumbnail.
open_graph_response["og:image"] = oembed["url"]
url = oembed.get("url")
if url and isinstance(url, str):
open_graph_response["og:image"] = url
elif oembed_type == "video":
open_graph_response["og:type"] = "video.other"
html = oembed.get("html")
if html and isinstance(html, str):
calc_description_and_urls(open_graph_response, oembed["html"])
open_graph_response["og:video:width"] = oembed["width"]
open_graph_response["og:video:height"] = oembed["height"]
for size in ("width", "height"):
val = oembed.get(size)
if val is not None and isinstance(val, int):
open_graph_response[f"og:video:{size}"] = val
elif oembed_type == "link":
open_graph_response["og:type"] = "website"
else:
raise RuntimeError(f"Unknown oEmbed type: {oembed_type}")
except Exception as e:
# Trap any exception and let the code follow as usual.
logger.warning("Error parsing oEmbed metadata from %s: %r", url, e)
open_graph_response = {}
author_name = None
cache_age = None
logger.warning("Unknown oEmbed type: %s", oembed_type)
return OEmbedResult(open_graph_response, author_name, cache_age)

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@ -14,6 +14,8 @@
import json
from parameterized import parameterized
from twisted.test.proto_helpers import MemoryReactor
from synapse.rest.media.v1.oembed import OEmbedProvider, OEmbedResult
@ -23,8 +25,16 @@ from synapse.util import Clock
from tests.unittest import HomeserverTestCase
try:
import lxml
except ImportError:
lxml = None
class OEmbedTests(HomeserverTestCase):
if not lxml:
skip = "url preview feature requires lxml"
def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
self.oembed = OEmbedProvider(hs)
@ -36,7 +46,7 @@ class OEmbedTests(HomeserverTestCase):
def test_version(self) -> None:
"""Accept versions that are similar to 1.0 as a string or int (or missing)."""
for version in ("1.0", 1.0, 1):
result = self.parse_response({"version": version, "type": "link"})
result = self.parse_response({"version": version})
# An empty Open Graph response is an error, ensure the URL is included.
self.assertIn("og:url", result.open_graph_result)
@ -49,3 +59,94 @@ class OEmbedTests(HomeserverTestCase):
result = self.parse_response({"version": version, "type": "link"})
# An empty Open Graph response is an error, ensure the URL is included.
self.assertEqual({}, result.open_graph_result)
def test_cache_age(self) -> None:
"""Ensure a cache-age is parsed properly."""
# Correct-ish cache ages are allowed.
for cache_age in ("1", 1.0, 1):
result = self.parse_response({"cache_age": cache_age})
self.assertEqual(result.cache_age, 1000)
# Invalid cache ages are ignored.
for cache_age in ("invalid", {}):
result = self.parse_response({"cache_age": cache_age})
self.assertIsNone(result.cache_age)
# Cache age is optional.
result = self.parse_response({})
self.assertIsNone(result.cache_age)
@parameterized.expand(
[
("title", "title"),
("provider_name", "site_name"),
("thumbnail_url", "image"),
],
name_func=lambda func, num, p: f"{func.__name__}_{p.args[0]}",
)
def test_property(self, oembed_property: str, open_graph_property: str) -> None:
"""Test properties which must be strings."""
result = self.parse_response({oembed_property: "test"})
self.assertIn(f"og:{open_graph_property}", result.open_graph_result)
self.assertEqual(result.open_graph_result[f"og:{open_graph_property}"], "test")
result = self.parse_response({oembed_property: 1})
self.assertNotIn(f"og:{open_graph_property}", result.open_graph_result)
def test_author_name(self) -> None:
"""Test the author_name property."""
result = self.parse_response({"author_name": "test"})
self.assertEqual(result.author_name, "test")
result = self.parse_response({"author_name": 1})
self.assertIsNone(result.author_name)
def test_rich(self) -> None:
"""Test a type of rich."""
result = self.parse_response({"html": "test<img src='foo'>", "type": "rich"})
self.assertIn("og:description", result.open_graph_result)
self.assertIn("og:image", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:description"], "test")
self.assertEqual(result.open_graph_result["og:image"], "foo")
result = self.parse_response({"type": "rich"})
self.assertNotIn("og:description", result.open_graph_result)
result = self.parse_response({"html": 1, "type": "rich"})
self.assertNotIn("og:description", result.open_graph_result)
def test_photo(self) -> None:
"""Test a type of photo."""
result = self.parse_response({"url": "test", "type": "photo"})
self.assertIn("og:image", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:image"], "test")
result = self.parse_response({"type": "photo"})
self.assertNotIn("og:image", result.open_graph_result)
result = self.parse_response({"url": 1, "type": "photo"})
self.assertNotIn("og:image", result.open_graph_result)
def test_video(self) -> None:
"""Test a type of video."""
result = self.parse_response({"html": "test", "type": "video"})
self.assertIn("og:type", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:type"], "video.other")
self.assertIn("og:description", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:description"], "test")
result = self.parse_response({"type": "video"})
self.assertIn("og:type", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:type"], "video.other")
self.assertNotIn("og:description", result.open_graph_result)
result = self.parse_response({"url": 1, "type": "video"})
self.assertIn("og:type", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:type"], "video.other")
self.assertNotIn("og:description", result.open_graph_result)
def test_link(self) -> None:
"""Test type of link."""
result = self.parse_response({"type": "link"})
self.assertIn("og:type", result.open_graph_result)
self.assertEqual(result.open_graph_result["og:type"], "website")