libervia-backend: libervia/backend/plugins/plugin_misc_url

comparison libervia/backend/plugins/plugin_misc_url_preview.py @ 4103:eaa0daa7f834

plugin URL preview: URL preview first draft

author	Goffi <goffi@goffi.org>
date	Tue, 27 Jun 2023 15:48:15 +0200
parents
children	0d7bb4df2343

comparison

equal deleted inserted replaced

-:c0bb4b3fdccf
+:eaa0daa7f834
+#!/usr/bin/env python3
+# Libervia plugin to handle events
+# Copyright (C) 2009-2022 Jérôme Poisson (goffi@goffi.org)
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+from dataclasses import dataclass
+import json
+from textwrap import dedent
+from typing import Callable, Dict, List, Optional, Union
+from urllib import parse
+import fnmatch
+from lxml import etree
+import treq
+from twisted.internet import defer
+from libervia.backend.core.constants import Const as C
+from libervia.backend.core.core_types import SatXMPPEntity
+from libervia.backend.core.exceptions import ConflictError
+from libervia.backend.core.i18n import _
+from libervia.backend.core.log import getLogger
+from libervia.backend.tools.common import data_format
+from libervia.backend.tools.common.async_utils import async_lru
+log = getLogger(__name__)
+PLUGIN_INFO = {
+C.PI_NAME: "Preview",
+C.PI_IMPORT_NAME: "Preview",
+C.PI_TYPE: C.PLUG_TYPE_MISC,
+C.PI_PROTOCOLS: ["Open Graph", "oEmbed"],
+C.PI_DEPENDENCIES: ["TEXT_SYNTAXES"],
+C.PI_MAIN: "Preview",
+C.PI_HANDLER: "no",
+C.PI_DESCRIPTION: dedent(
+_(
+"""\
+Retrieves and provides a preview of URLs using various protocols. Initially, it
+uses the Open Graph protocol for most web pages. Specialized handlers are
+implemented for YouTube using the oEmbed protocol.
+"""
+)
+),
+}
+OG_TAGS = [
+"title",
+"type",
+"image",
+"url",
+"audio",
+"description",
+"determiner",
+"locale",
+"locale:alternate",
+"site_name",
+"video",
+]
+class PreviewFetchError(Exception):
+pass
+@dataclass
+class Protocol:
+name: str
+callback: Callable
+priority: int
+class Preview:
+protocols: Dict[str, Protocol] = {}
+domain_protocols: Dict[str, str] = {}
+def __init__(self, host):
+log.info(_("Preview plugin initialization"))
+self.host = host
+# generic protocols
+self.register("open_graph", self.fetch_open_graph_data, priority=100)
+self.register("oembed", self.fetch_generic_oembed_data, priority=50)
+self.register("generic", self.fetch_generic_data, priority=0)
+# domain specific protocols
+self.register("oembed-youtube", self.fetch_youtube_oembed_data, priority=-100)
+self.register_domain_protocol(
+["www.youtube.com", "youtu.be", "m.youtube.com"], "oembed-youtube"
+)
+self.register("wikipedia", self.fetch_wikipedia_data, priority=-80)
+self.register_domain_protocol(["*.wikipedia.org"], "wikipedia")
+self.register("invidious", self.fetch_invidious_data, priority=-90)
+self.register_domain_protocol(
+["yewtu.be", "www.yewtu.be", "invidious.fdn.fr"],
+"invidious"
+)
+# bridge methods
+host.bridge.add_method(
+"url_preview_get",
+".plugin",
+in_sign="sss",
+out_sign="s",
+method=self._url_preview_get,
+async_=True,
+)
+# API
+def _url_preview_get(self, url: str, options: str, profile_key: str) -> defer.Deferred:
+client = self.host.get_client(profile_key)
+d = defer.ensureDeferred(
+self.get_preview_data(client, url, data_format.deserialise(options))
+)
+d.addCallback(data_format.serialise)
+return d
+@async_lru()
+async def get_preview_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch preview data from a url using registered protocols
+@param url: The url to fetch the preview data from
+@param options: Additional options that may be used while fetching preview data
+@return: A dictionary containing the preview data or None if no data could be
+fetched
+"""
+parsed_url = parse.urlparse(url)
+domain = parsed_url.netloc
+preview_data: Optional[dict] = None
+matched_protocol = None
+for registered_domain, registered_protocol in self.domain_protocols.items():
+if fnmatch.fnmatch(domain, registered_domain):
+matched_protocol = registered_protocol
+break
+if matched_protocol is not None:
+callback = self.protocols[matched_protocol].callback
+preview_data = await callback(client, url, options)
+else:
+for name, protocol in sorted(
+self.protocols.items(), key=lambda item: item[1].priority, reverse=True
+):
+try:
+preview_data = await protocol.callback(client, url, options)
+except Exception as e:
+log.warning(f"Can't run protocol {name} for {url}: {e}")
+else:
+if preview_data is not None:
+matched_protocol = protocol.name
+break
+if preview_data is not None:
+preview_data["protocol"] = matched_protocol
+# we don't clean html for youtube as we need Javascript to make it work, and
+# for invidious as we generate it ourself
+if "html" in preview_data:
+if matched_protocol in ("oembed-youtube", "invidious"):
+# this flag indicate that we know the source of HTML and we should be
+# able to trust it. This will add `allow-scripts` and
+# `allow-same-origin` in the preview <iframe> "sandbox" attribute
+preview_data["html_known"] = True
+else:
+preview_data["html_known"] = False
+clean_xhtml = self.host.plugins["TEXT_SYNTAXES"].clean_xhtml
+try:
+preview_data["html"] = clean_xhtml(preview_data["html"])
+except Exception as e:
+log.warning(f"Can't clean html data: {e}\n{preview_data}")
+del preview_data["html"]
+return preview_data
+@classmethod
+def register(cls, name: str, callback: Callable, priority: int = 0):
+"""Register a protocol to retrieve preview data
+The registered callback should return a dictionary of preview data if available,
+or None otherwise.
+@param name: Unique name of the protocol
+@param callback: Async callback function to fetch preview data
+@param priority: Priority of the protocol, with higher numbers indicating higher
+priority
+@return: None
+"""
+if name in cls.protocols:
+raise ConflictError(f"Protocol with the name {name} is already registered.")
+cls.protocols[name] = Protocol(name=name, callback=callback, priority=priority)
+@classmethod
+def register_domain_protocol(cls, domains: Union[str, List[str]], protocol_name: str):
+"""Register a protocol for a specific domain or list of domains
+@param domains: The domain name or list of domain names
+@param protocol_name: The name of the protocol to be associated with the domain(s)
+@return: None
+"""
+protocol_name = protocol_name.replace(" ", "").lower()
+if protocol_name not in cls.protocols:
+raise ConflictError(
+f"Protocol with the name {protocol_name} is not registered."
+)
+if isinstance(domains, str):
+domains = [domains]
+for domain in domains:
+domain = domain.strip()
+if not domain:
+log.warning("empty string used as domain, ignoring")
+continue
+cls.domain_protocols[domain] = protocol_name
+# Open Graph
+async def fetch_open_graph_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch Open Graph data from a url
+This method implements the Open Graph protocol, details of which can be found at:
+http://ogp.me/
+@param url: The url to fetch the Open Graph data from
+@param options: Additional options that may be used while fetching data
+@return: A dictionary containing the Open Graph data or None if no data could be
+fetched
+"""
+resp = await treq.get(url)
+if resp.code == 200:
+html = await resp.text()
+parser = etree.HTMLParser()
+tree = etree.fromstring(html, parser)
+# Extract Open Graph data
+metadata = {}
+for tag in OG_TAGS:
+og_el = tree.find('.//meta[@property="og:{tag}"]'.format(tag=tag))
+if og_el is not None:
+metadata[tag] = og_el.get("content")
+if metadata:
+if "site_name" in metadata and not "provider_name" in metadata:
+metadata["provider_name"] = metadata["site_name"]
+return metadata
+return None
+else:
+raise PreviewFetchError(
+f"Failed to fetch preview for {url}, status code: {resp.code}"
+)
+# oEmbed
+async def _fetch_oembed_data(self, oembed_url: str) -> Optional[dict]:
+"""Fetch oEmbed data from a given oEmbed URL
+@param oembed_url: The url to fetch the oEmbed data from
+@return: A dictionary containing the oEmbed data or None if no data could be
+fetched
+"""
+resp = await treq.get(oembed_url)
+if resp.code == 200:
+return json.loads(await resp.text())
+else:
+raise PreviewFetchError(
+f"Failed to fetch oEmbed preview for {oembed_url}, status code: "
+f"{resp.code}"
+)
+async def fetch_youtube_oembed_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch YouTube oEmbed data from a url
+@param url: The url to fetch the YouTube oEmbed data from
+@param options: Additional options that may be used while fetching data
+@return: A dictionary containing the YouTube oEmbed data or None if no data could
+be fetched
+"""
+oembed_url = f"https://www.youtube.com/oembed?url={parse.quote(url)}&format=json"
+data = await self._fetch_oembed_data(oembed_url)
+if data is not None and 'html' in data:
+html = data['html']
+root = etree.HTML(html)
+iframe_elt = root.xpath('//iframe')
+if iframe_elt:
+iframe_elt[0].attrib['style'] = (
+'position: absolute; top: 0; left: 0; width: 100%; height: 100%;'
+)
+data['html'] = etree.tostring(root, method='html', encoding='unicode')
+else:
+log.warning("No <iframe> found in the YouTube oEmbed response")
+return data
+async def fetch_generic_oembed_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch generic oEmbed data from a url
+@param url: The url to fetch the oEmbed data from
+@param options: Additional options that may be used while fetching data
+@return: A dictionary containing the oEmbed data or None if no data could be
+fetched
+"""
+resp = await treq.get(url)
+if resp.code == 200:
+html = await resp.text()
+parser = etree.HTMLParser()
+tree = etree.fromstring(html, parser)
+# Find oEmbed URL
+oembed_link = tree.find('.//link[@type="application/json+oembed"]')
+if oembed_link is not None:
+oembed_url = oembed_link.get("href")
+return await self._fetch_oembed_data(oembed_url)
+else:
+return None
+else:
+raise PreviewFetchError(
+f"Failed to fetch preview for {url}, status code: {resp.code}"
+)
+async def fetch_generic_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch generic data from a url
+This method attempts to extract the title, description, and author metadata from
+the HTML of the page. If these data cannot be found, the method will return None.
+@param url: The url to fetch the generic data from
+@param options: Additional options that may be used while fetching data
+@return: A dictionary containing the generic data or None if no data could be
+fetched
+"""
+resp = await treq.get(url)
+if resp.code == 200:
+html = await resp.text()
+parser = etree.HTMLParser()
+tree = etree.fromstring(html, parser)
+# Find title, description, and author metadata
+title_el = tree.find(".//title")
+desc_el = tree.find('.//meta[@name="description"]')
+author_el = tree.find('.//meta[@name="author"]')
+metadata = {
+"title": title_el.text if title_el is not None else "",
+"description": desc_el.get("content") if desc_el is not None else "",
+"author_name": author_el.get("content") if author_el is not None else "",
+"url": url,
+"provider_name": parse.urlparse(url).netloc,
+"provider_url": f"{parse.urlparse(url).scheme}://{parse.urlparse(url).netloc}",
+}
+return metadata if any(metadata.values()) else None
+else:
+raise PreviewFetchError(
+f"Failed to fetch generic preview for {url}, status code: {resp.code}"
+)
+# Wikipedia
+async def fetch_wikipedia_data(
+self, client: SatXMPPEntity, url: str, options: dict
+) -> Optional[dict]:
+"""Fetch Wikipedia data from a url
+This method implements the Wikipedia API, details of which can be found at:
+https://www.mediawiki.org/wiki/API:Main_page
+@param url: The url to fetch the Wikipedia data from
+@param options: Additional options that may be used while fetching data
+@return: A dictionary containing the Wikipedia data or None if no data could be
+fetched
+"""
+parsed_url = parse.urlparse(url)
+page_name = parsed_url.path.split("/")[-1]
+# Use the Wikipedia API to get a summary of the page and a preview image
+api_url = (
+f"https://{parsed_url.netloc}/w/api.php?format=json&action=query&"
+f"prop=extracts|pageimages&exintro&explaintext&redirects=1&piprop=thumbnail"
+f"&pithumbsize=300&titles={page_name}"
+)
+resp = await treq.get(api_url)
+if resp.code == 200:
+data = json.loads(await resp.text())
+# The page ID is the first key in the "pages" dictionary
+page_id = next(iter(data["query"]["pages"].keys()))
+page = data["query"]["pages"][page_id]
+# The API may return a page with a missing title or extract if the page does
+# not exist
+if "missing" in page:
+return None
+return {
+"provider_name": "Wikipedia",
+"provider_url": "https://www.wikipedia.org",
+"title": page.get("title"),
+"description": page.get("extract"),
+"url": url,
+"image": page.get("thumbnail", {}).get("source")
+if "thumbnail" in page
+else None,
+}
+else:
+raise PreviewFetchError(
+f"Failed to fetch Wikipedia preview for {url}, status code: {resp.code}"
+)
+# Invidious
+async def fetch_invidious_data(self, client: SatXMPPEntity, url: str, options: dict) -> Optional[dict]:
+"""
+Fetch Invidious data from a url and generate HTML iframe.
+@param url: The url to fetch the Invidious data from.
+@param options: Additional options that may be used while fetching data.
+@return: A dictionary containing the Invidious data or None if no data could be fetched.
+"""
+parsed_url = parse.urlparse(url)
+if 'watch' in parsed_url.path:
+video_id = parse.parse_qs(parsed_url.query).get('v', [None])[0]
+else:
+video_id = parsed_url.path.strip('/')
+if not video_id:
+log.warning(f"Can't extract video ID from {url}")
+return None
+invidious_api_url = f"https://{parsed_url.netloc}/api/v1/videos/{video_id}"
+resp = await treq.get(invidious_api_url)
+if resp.code == 200:
+video_data = await resp.json()
+# construct the iframe html code
+html = (
+f'<iframe'
+f'    width="100%"'
+f'    height="auto"'
+f'    src="https://{parsed_url.netloc}/embed/{video_id}"'
+f'    frameborder="0" '
+f'    allow="'
+f'        accelerometer;'
+f'        autoplay;'
+f'        clipboard-write;'
+f'        encrypted-media;'
+f'        gyroscope;'
+f'        picture-in-picture"'
+f'    style="'
+f'        position: absolute;'
+f'        top: 0;'
+f'        left: 0;'
+f'        width: 100%;'
+f'        height: 100%;"'
+f'    allowfullscreen></iframe>'
+)
+# structure the data to be returned
+data = {
+"title": video_data.get("title"),
+"description": video_data.get("description"),
+"url": url,
+"image": video_data.get("videoThumbnails", [{}])[0].get("url"),
+"provider_name": "Invidious",
+"provider_url": f"https://{parsed_url.netloc}",
+"html": html,
+"author_name": video_data.get("author"),
+"author_url": f"https://{parsed_url.netloc}/channel/{video_data.get('authorId')}",
+}
+return data
+else:
+log.warning(f"Unable to fetch video data from Invidious API for {video_id}")
+return None

Mercurial > libervia-backend

comparison libervia/backend/plugins/plugin_misc_url_preview.py @ 4103:eaa0daa7f834