diff --git a/synapse/config/homeserver.py b/synapse/config/homeserver.py
index 1f42a51857..442f1b9ac0 100644
--- a/synapse/config/homeserver.py
+++ b/synapse/config/homeserver.py
@@ -30,6 +30,7 @@ from .key import KeyConfig
from .logger import LoggingConfig
from .metrics import MetricsConfig
from .modules import ModulesConfig
+from .oembed import OembedConfig
from .oidc import OIDCConfig
from .password_auth_providers import PasswordAuthProviderConfig
from .push import PushConfig
@@ -65,6 +66,7 @@ class HomeServerConfig(RootConfig):
LoggingConfig,
RatelimitConfig,
ContentRepositoryConfig,
+ OembedConfig,
CaptchaConfig,
VoipConfig,
RegistrationConfig,
diff --git a/synapse/config/oembed.py b/synapse/config/oembed.py
new file mode 100644
index 0000000000..09267b5eef
--- /dev/null
+++ b/synapse/config/oembed.py
@@ -0,0 +1,180 @@
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import json
+import re
+from typing import Any, Dict, Iterable, List, Pattern
+from urllib import parse as urlparse
+
+import attr
+import pkg_resources
+
+from synapse.types import JsonDict
+
+from ._base import Config, ConfigError
+from ._util import validate_config
+
+
+@attr.s(slots=True, frozen=True, auto_attribs=True)
+class OEmbedEndpointConfig:
+ # The API endpoint to fetch.
+ api_endpoint: str
+ # The patterns to match.
+ url_patterns: List[Pattern]
+
+
+class OembedConfig(Config):
+ """oEmbed Configuration"""
+
+ section = "oembed"
+
+ def read_config(self, config, **kwargs):
+ oembed_config: Dict[str, Any] = config.get("oembed") or {}
+
+ # A list of patterns which will be used.
+ self.oembed_patterns: List[OEmbedEndpointConfig] = list(
+ self._parse_and_validate_providers(oembed_config)
+ )
+
+ def _parse_and_validate_providers(
+ self, oembed_config: dict
+ ) -> Iterable[OEmbedEndpointConfig]:
+ """Extract and parse the oEmbed providers from the given JSON file.
+
+ Returns a generator which yields the OidcProviderConfig objects
+ """
+ # Whether to use the packaged providers.json file.
+ if not oembed_config.get("disable_default_providers") or False:
+ providers = json.load(
+ pkg_resources.resource_stream("synapse", "res/providers.json")
+ )
+ yield from self._parse_and_validate_provider(
+ providers, config_path=("oembed",)
+ )
+
+ # The JSON files which includes additional provider information.
+ for i, file in enumerate(oembed_config.get("additional_providers") or []):
+ # TODO Error checking.
+ with open(file) as f:
+ providers = json.load(f)
+
+ yield from self._parse_and_validate_provider(
+ providers,
+ config_path=(
+ "oembed",
+ "additional_providers",
+ f"<item {i}>",
+ ),
+ )
+
+ def _parse_and_validate_provider(
+ self, providers: List[JsonDict], config_path: Iterable[str]
+ ) -> Iterable[OEmbedEndpointConfig]:
+ # Ensure it is the proper form.
+ validate_config(
+ _OEMBED_PROVIDER_SCHEMA,
+ providers,
+ config_path=config_path,
+ )
+
+ # Parse it and yield each result.
+ for provider in providers:
+ # Each provider might have multiple API endpoints, each which
+ # might have multiple patterns to match.
+ for endpoint in provider["endpoints"]:
+ api_endpoint = endpoint["url"]
+ patterns = [
+ self._glob_to_pattern(glob, config_path)
+ for glob in endpoint["schemes"]
+ ]
+ yield OEmbedEndpointConfig(api_endpoint, patterns)
+
+ def _glob_to_pattern(self, glob: str, config_path: Iterable[str]) -> Pattern:
+ """
+ Convert the glob into a sane regular expression to match against. The
+ rules followed will be slightly different for the domain portion vs.
+ the rest.
+
+ 1. The scheme must be one of HTTP / HTTPS (and have no globs).
+ 2. The domain can have globs, but we limit it to characters that can
+ reasonably be a domain part.
+ TODO: This does not attempt to handle Unicode domain names.
+ TODO: The domain should not allow wildcard TLDs.
+ 3. Other parts allow a glob to be any one, or more, characters.
+ """
+ results = urlparse.urlparse(glob)
+
+ # Ensure the scheme does not have wildcards (and is a sane scheme).
+ if results.scheme not in {"http", "https"}:
+ raise ConfigError(f"Insecure oEmbed scheme: {results.scheme}", config_path)
+
+ pattern = urlparse.urlunparse(
+ [
+ results.scheme,
+ re.escape(results.netloc).replace("\\*", "[a-zA-Z0-9_-]+"),
+ ]
+ + [re.escape(part).replace("\\*", ".+") for part in results[2:]]
+ )
+ return re.compile(pattern)
+
+ def generate_config_section(self, **kwargs):
+ return """\
+ # oEmbed allows for easier embedding content from a website. It can be
+ # used for generating URLs previews of services which support it.
+ #
+ oembed:
+ # A default list of oEmbed providers is included with Synapse.
+ #
+ # Uncomment the following to disable using these default oEmbed URLs.
+ # Defaults to 'false'.
+ #
+ #disable_default_providers: true
+
+ # Additional files with oEmbed configuration (each should be in the
+ # form of providers.json).
+ #
+ # By default, this list is empty (so only the default providers.json
+ # is used).
+ #
+ #additional_providers:
+ # - oembed/my_providers.json
+ """
+
+
+_OEMBED_PROVIDER_SCHEMA = {
+ "type": "array",
+ "items": {
+ "type": "object",
+ "properties": {
+ "provider_name": {"type": "string"},
+ "provider_url": {"type": "string"},
+ "endpoints": {
+ "type": "array",
+ "items": {
+ "type": "object",
+ "properties": {
+ "schemes": {
+ "type": "array",
+ "items": {"type": "string"},
+ },
+ "url": {"type": "string"},
+ "formats": {"type": "array", "items": {"type": "string"}},
+ "discovery": {"type": "boolean"},
+ },
+ "required": ["schemes", "url"],
+ },
+ },
+ },
+ "required": ["provider_name", "provider_url", "endpoints"],
+ },
+}
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