174 lines
6.5 KiB
Java
174 lines
6.5 KiB
Java
package org.schabi.newpipe.extractor.services.youtube;
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import org.jsoup.Jsoup;
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import org.jsoup.nodes.Document;
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import org.jsoup.nodes.Element;
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import org.jsoup.select.Elements;
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import org.schabi.newpipe.extractor.NewPipe;
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import org.schabi.newpipe.extractor.exceptions.ParsingException;
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import org.schabi.newpipe.extractor.localization.Localization;
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import org.schabi.newpipe.extractor.utils.Parser;
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import javax.annotation.Nonnull;
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import java.util.regex.Pattern;
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/**
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* The extractor of YouTube's base JavaScript player file.
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*
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* <p>
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* YouTube restrict streaming their media in multiple ways by requiring their HTML5 clients to use
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* a signature timestamp, and on streaming URLs a signature deobfuscation function for some
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* contents and a throttling parameter deobfuscation one for all contents.
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* </p>
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*
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* <p>
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* This class handles fetching of this base JavaScript player file in order to allow other classes
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* to extract the needed data.
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* </p>
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*
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* <p>
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* It will try to get the player URL from YouTube's IFrame resource first, and from a YouTube embed
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* watch page as a fallback.
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* </p>
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*/
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public final class YoutubeJavaScriptExtractor {
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private static final String HTTPS = "https:";
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private static final String BASE_JS_PLAYER_URL_FORMAT =
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"https://www.youtube.com/s/player/%s/player_ias.vflset/en_GB/base.js";
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private static final Pattern IFRAME_RES_JS_BASE_PLAYER_HASH_PATTERN = Pattern.compile(
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"player\\\\/([a-z0-9]{8})\\\\/");
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private static final Pattern EMBEDDED_WATCH_PAGE_JS_BASE_PLAYER_URL_PATTERN = Pattern.compile(
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"\"jsUrl\":\"(/s/player/[A-Za-z0-9]+/player_ias\\.vflset/[A-Za-z_-]+/base\\.js)\"");
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private static String cachedJavaScriptCode;
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private YoutubeJavaScriptExtractor() {
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}
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/**
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* Extracts the JavaScript file.
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*
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* <p>
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* The result is cached, so subsequent calls use the result of previous calls.
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* </p>
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*
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* @param videoId a YouTube video ID, which doesn't influence the result, but it may help in
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* the chance that YouTube track it
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* @return the whole JavaScript file as a string
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* @throws ParsingException if the extraction failed
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*/
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@Nonnull
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public static String extractJavaScriptCode(@Nonnull final String videoId)
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throws ParsingException {
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if (cachedJavaScriptCode == null) {
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String url;
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try {
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url = YoutubeJavaScriptExtractor.extractJavaScriptUrlWithIframeResource();
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} catch (final Exception e) {
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url = YoutubeJavaScriptExtractor.extractJavaScriptUrlWithEmbedWatchPage(videoId);
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}
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final String playerJsUrl = YoutubeJavaScriptExtractor.cleanJavaScriptUrl(url);
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cachedJavaScriptCode = YoutubeJavaScriptExtractor.downloadJavaScriptCode(playerJsUrl);
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}
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return cachedJavaScriptCode;
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}
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/**
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* Reset the cached JavaScript code.
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*
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* <p>
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* It will be fetched again the next time {@link #extractJavaScriptCode(String)} is called.
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* </p>
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*/
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public static void resetJavaScriptCode() {
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cachedJavaScriptCode = null;
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}
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@Nonnull
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static String extractJavaScriptUrlWithIframeResource() throws ParsingException {
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final String iframeUrl;
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final String iframeContent;
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try {
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iframeUrl = "https://www.youtube.com/iframe_api";
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iframeContent = NewPipe.getDownloader()
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.get(iframeUrl, Localization.DEFAULT)
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.responseBody();
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} catch (final Exception e) {
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throw new ParsingException("Could not fetch IFrame resource", e);
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}
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try {
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final String hash = Parser.matchGroup1(
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IFRAME_RES_JS_BASE_PLAYER_HASH_PATTERN, iframeContent);
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return String.format(BASE_JS_PLAYER_URL_FORMAT, hash);
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} catch (final Parser.RegexException e) {
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throw new ParsingException(
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"IFrame resource didn't provide JavaScript base player's hash", e);
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}
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}
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@Nonnull
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static String extractJavaScriptUrlWithEmbedWatchPage(@Nonnull final String videoId)
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throws ParsingException {
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final String embedUrl;
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final String embedPageContent;
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try {
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embedUrl = "https://www.youtube.com/embed/" + videoId;
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embedPageContent = NewPipe.getDownloader()
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.get(embedUrl, Localization.DEFAULT)
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.responseBody();
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} catch (final Exception e) {
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throw new ParsingException("Could not fetch embedded watch page", e);
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}
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// Parse HTML response with jsoup and look at script elements first
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final Document doc = Jsoup.parse(embedPageContent);
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final Elements elems = doc.select("script")
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.attr("name", "player/base");
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for (final Element elem : elems) {
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// Script URLs should be relative and not absolute
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final String playerUrl = elem.attr("src");
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if (playerUrl.contains("base.js")) {
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return playerUrl;
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}
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}
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// Use regexes to match the URL in a JavaScript embedded script of the HTML page
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try {
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return Parser.matchGroup1(
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EMBEDDED_WATCH_PAGE_JS_BASE_PLAYER_URL_PATTERN, embedPageContent);
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} catch (final Parser.RegexException e) {
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throw new ParsingException(
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"Embedded watch page didn't provide JavaScript base player's URL", e);
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}
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}
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@Nonnull
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private static String cleanJavaScriptUrl(@Nonnull final String playerJsUrl) {
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if (playerJsUrl.startsWith("//")) {
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// https part has to be added manually if the URL is protocol-relative
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return HTTPS + playerJsUrl;
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} else if (playerJsUrl.startsWith("/")) {
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// https://www.youtube.com part has to be added manually if the URL is relative to
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// YouTube's domain
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return HTTPS + "//www.youtube.com" + playerJsUrl;
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} else {
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return playerJsUrl;
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}
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}
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@Nonnull
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private static String downloadJavaScriptCode(@Nonnull final String playerJsUrl)
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throws ParsingException {
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try {
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return NewPipe.getDownloader()
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.get(playerJsUrl, Localization.DEFAULT)
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.responseBody();
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} catch (final Exception e) {
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throw new ParsingException(
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"Could not get JavaScript base player's code from URL: " + playerJsUrl, e);
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}
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}
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}
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