109 lines
3.4 KiB
JavaScript
109 lines
3.4 KiB
JavaScript
import util from 'util';
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import fetch from 'node-fetch';
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const YOUTUBE_BASE = 'https://www.youtube.com/%s';
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const WATCH_BASE = util.format(YOUTUBE_BASE, 'watch?v=%s');
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const PLAYER_CONFIG_REGEX = /ytplayer\.config = (\{.*?\});/;
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/**
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* Make a promise that is resolved in a point in the future.
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*
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* @param Number time Time to wait before resolving the promise (ms).
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* @return null
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*/
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const sleep = time => new Promise(resolve => setTimeout(resolve, time));
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/**
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* Fetch the `ytplayer.config` object for a YouTube video.
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*
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* @async
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* @param String videoId Identifier of the video to fetch.
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* @param Number retries Allowed number of retries after fetch errors.
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* @param Number cooldown Time to wait before retrying (ms).
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* @return Object The player configuration object.
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*/
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export const getPlayerConfig = async (videoId, retries = 3, cooldown = 1000) =>
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{
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const url = util.format(WATCH_BASE, videoId);
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const res = await fetch(url);
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const body = await res.text();
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// Look for the definition of ytplayer.config and unserialize it
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const configSearch = body.match(PLAYER_CONFIG_REGEX);
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if (configSearch === null)
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{
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if (retries > 0)
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{
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console.info(`Error while fetching ${videoId}, retrying in ${cooldown} ms`);
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await sleep(cooldown);
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return getPlayerConfig(videoId, retries - 1, cooldown * 2);
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}
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else
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{
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throw new Error('Unable to find player configuration');
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}
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}
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const config = JSON.parse(configSearch[1]);
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config.args.player_response = JSON.parse(config.args.player_response);
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return config;
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};
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/**
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* Get metadata about a YouTube video.
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*
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* @param playerConfig The `ytplayer.config` object corresponding to the source
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* YouTube video, as obtained from `getPlayerConfig`.
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* @return Object containing the video metadata.
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*/
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export const getVideoMeta = playerConfig => ({
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videoId: playerConfig.args.player_response.videoDetails.videoId,
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title: playerConfig.args.player_response.videoDetails.title,
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});
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/**
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* Find videos linked from the endscreen of a YouTube video.
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*
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* @param playerConfig The `ytplayer.config` object corresponding to the source
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* YouTube video, as obtained from `getPlayerConfig`.
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* @return List of identifiers of linked videos.
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*/
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export const getEndScreenVideos = playerConfig =>
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{
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const response = playerConfig.args.player_response;
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if (!('endscreen' in response))
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{
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return [];
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}
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return response.endscreen.endscreenRenderer.elements
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.map(elt => elt.endscreenElementRenderer)
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.filter(rdr => 'watchEndpoint' in rdr.endpoint)
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.map(rdr => rdr.endpoint.watchEndpoint.videoId);
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};
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/**
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* Find videos linked from as cards from a YouTube video.
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*
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* @param playerConfig The `ytplayer.config` object corresponding to the source
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* YouTube video, as obtained from `getPlayerConfig`.
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* @return List of identifiers of linked videos.
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*/
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export const getCardVideos = playerConfig =>
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{
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const response = playerConfig.args.player_response;
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if (!('cards' in response))
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{
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return [];
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}
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return response.cards.cardCollectionRenderer.cards
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.map(card => card.cardRenderer.content)
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.filter(content => 'videoInfoCardContentRenderer' in content)
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.map(content => content.videoInfoCardContentRenderer)
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.map(rdr => rdr.action.watchEndpoint.videoId);
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};
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