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Diffstat (limited to 'synapse/rest/media/v1/oembed.py')
| -rw-r--r-- | synapse/rest/media/v1/oembed.py | 265 |
1 files changed, 0 insertions, 265 deletions
diff --git a/synapse/rest/media/v1/oembed.py b/synapse/rest/media/v1/oembed.py deleted file mode 100644 index 7592aa5d47..0000000000 --- a/synapse/rest/media/v1/oembed.py +++ /dev/null @@ -1,265 +0,0 @@ -# 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 html -import logging -import urllib.parse -from typing import TYPE_CHECKING, List, Optional - -import attr - -from synapse.rest.media.v1.preview_html import parse_html_description -from synapse.types import JsonDict -from synapse.util import json_decoder - -if TYPE_CHECKING: - from lxml import etree - - from synapse.server import HomeServer - -logger = logging.getLogger(__name__) - - -@attr.s(slots=True, frozen=True, auto_attribs=True) -class OEmbedResult: - # The Open Graph result (converted from the oEmbed result). - open_graph_result: JsonDict - # The author_name of the oEmbed result - author_name: Optional[str] - # Number of milliseconds to cache the content, according to the oEmbed response. - # - # This will be None if no cache-age is provided in the oEmbed response (or - # if the oEmbed response cannot be turned into an Open Graph response). - cache_age: Optional[int] - - -class OEmbedProvider: - """ - A helper for accessing oEmbed content. - - It can be used to check if a URL should be accessed via oEmbed and for - requesting/parsing oEmbed content. - """ - - def __init__(self, hs: "HomeServer"): - self._oembed_patterns = {} - for oembed_endpoint in hs.config.oembed.oembed_patterns: - api_endpoint = oembed_endpoint.api_endpoint - - # Only JSON is supported at the moment. This could be declared in - # the formats field. Otherwise, if the endpoint ends in .xml assume - # it doesn't support JSON. - if ( - oembed_endpoint.formats is not None - and "json" not in oembed_endpoint.formats - ) or api_endpoint.endswith(".xml"): - logger.info( - "Ignoring oEmbed endpoint due to not supporting JSON: %s", - api_endpoint, - ) - continue - - # Iterate through each URL pattern and point it to the endpoint. - for pattern in oembed_endpoint.url_patterns: - self._oembed_patterns[pattern] = api_endpoint - - def get_oembed_url(self, url: str) -> Optional[str]: - """ - Check whether the URL should be downloaded as oEmbed content instead. - - Args: - url: The URL to check. - - Returns: - A URL to use instead or None if the original URL should be used. - """ - for url_pattern, endpoint in self._oembed_patterns.items(): - if url_pattern.fullmatch(url): - # TODO Specify max height / width. - - # Note that only the JSON format is supported, some endpoints want - # this in the URL, others want it as an argument. - endpoint = endpoint.replace("{format}", "json") - - args = {"url": url, "format": "json"} - query_str = urllib.parse.urlencode(args, True) - return f"{endpoint}?{query_str}" - - # No match. - return None - - def autodiscover_from_html(self, tree: "etree.Element") -> Optional[str]: - """ - Search an HTML document for oEmbed autodiscovery information. - - Args: - tree: The parsed HTML body. - - Returns: - The URL to use for oEmbed information, or None if no URL was found. - """ - # Search for link elements with the proper rel and type attributes. - for tag in tree.xpath( - "//link[@rel='alternate'][@type='application/json+oembed']" - ): - if "href" in tag.attrib: - return tag.attrib["href"] - - # Some providers (e.g. Flickr) use alternative instead of alternate. - for tag in tree.xpath( - "//link[@rel='alternative'][@type='application/json+oembed']" - ): - if "href" in tag.attrib: - return tag.attrib["href"] - - return None - - def parse_oembed_response(self, url: str, raw_body: bytes) -> OEmbedResult: - """ - Parse the oEmbed response into an Open Graph response. - - Args: - url: The URL which is being previewed (not the one which was - requested). - raw_body: The oEmbed response as JSON encoded as bytes. - - Returns: - json-encoded Open Graph data - """ - - 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: - return OEmbedResult({}, None, None) - - # 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 oEmbed response converted to Open Graph. - open_graph_response: JsonDict = {"og:url": url} - - title = oembed.get("title") - if title and isinstance(title, str): - # A common WordPress plug-in seems to incorrectly escape entities - # in the oEmbed response. - open_graph_response["og:title"] = html.unescape(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 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. - 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.get("type") - if oembed_type == "rich": - html_str = oembed.get("html") - if isinstance(html_str, str): - calc_description_and_urls(open_graph_response, html_str) - - elif oembed_type == "photo": - # If this is a photo, use the full image, not the thumbnail. - 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_str = oembed.get("html") - if html_str and isinstance(html_str, str): - calc_description_and_urls(open_graph_response, oembed["html"]) - for size in ("width", "height"): - val = oembed.get(size) - if type(val) is int: - open_graph_response[f"og:video:{size}"] = val - - elif oembed_type == "link": - open_graph_response["og:type"] = "website" - - else: - logger.warning("Unknown oEmbed type: %s", oembed_type) - - return OEmbedResult(open_graph_response, author_name, cache_age) - - -def _fetch_urls(tree: "etree.Element", tag_name: str) -> List[str]: - results = [] - for tag in tree.xpath("//*/" + tag_name): - if "src" in tag.attrib: - results.append(tag.attrib["src"]) - return results - - -def calc_description_and_urls(open_graph_response: JsonDict, html_body: str) -> None: - """ - Calculate description for an HTML document. - - This uses lxml to convert the HTML document into plaintext. If errors - occur during processing of the document, an empty response is returned. - - Args: - open_graph_response: The current Open Graph summary. This is updated with additional fields. - html_body: The HTML document, as bytes. - - Returns: - The summary - """ - # If there's no body, nothing useful is going to be found. - if not html_body: - return - - from lxml import etree - - # Create an HTML parser. If this fails, log and return no metadata. - parser = etree.HTMLParser(recover=True, encoding="utf-8") - - # Attempt to parse the body. If this fails, log and return no metadata. - tree = etree.fromstring(html_body, parser) - - # The data was successfully parsed, but no tree was found. - if tree is None: - return - - # Attempt to find interesting URLs (images, videos, embeds). - if "og:image" not in open_graph_response: - image_urls = _fetch_urls(tree, "img") - if image_urls: - open_graph_response["og:image"] = image_urls[0] - - video_urls = _fetch_urls(tree, "video") + _fetch_urls(tree, "embed") - if video_urls: - open_graph_response["og:video"] = video_urls[0] - - description = parse_html_description(tree) - if description: - open_graph_response["og:description"] = description |