[SoundCloud] Fix extraction of client id

- Hardcoded id and check at the first usage.
- As a fallback, and considering that the scripts containing the client
id were all split up, try searching it in each of them.

Author: mauriciocolli

extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudParsingHelper.java

@@ -7,9 +7,12 @@
 import org.jsoup.Jsoup;
 import org.jsoup.nodes.Document;
 import org.jsoup.nodes.Element;
+import org.jsoup.select.Elements;
+import org.schabi.newpipe.extractor.DownloadResponse;
 import org.schabi.newpipe.extractor.Downloader;
 import org.schabi.newpipe.extractor.NewPipe;
 import org.schabi.newpipe.extractor.channel.ChannelInfoItemsCollector;
+import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.exceptions.ReCaptchaException;
 import org.schabi.newpipe.extractor.stream.StreamInfoItemsCollector;
@@ -21,6 +24,7 @@
 import java.net.URLEncoder;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
+import java.util.Collections;
 import java.util.Date;
 import java.util.HashMap;
 
@@ -32,29 +36,43 @@ public class SoundcloudParsingHelper {
     private SoundcloudParsingHelper() {
     }
 
-    public static String clientId() throws ReCaptchaException, IOException, RegexException {
+    public static String clientId() throws ExtractionException, IOException {
         if (clientId != null && !clientId.isEmpty()) return clientId;
 
         Downloader dl = NewPipe.getDownloader();
-        String response = dl.download("https://soundcloud.com");
-
-        Document doc = Jsoup.parse(response);
-        Element jsElement = doc.select("script[src^=https://a-v2.sndcdn.com/assets/app]").first();
+        clientId = "LHzSAKe8eP9Yy3FgBugfBapRPLncO6Ng"; // Updated on 22/10/19
+        final String apiUrl = "https://api.soundcloud.com/connect?client_id=" + clientId;
+        // Should return 200 to indicate that the client id is valid, a 401 is returned otherwise.
+        // In that case, the fallback method is used.
+        if (dl.head(apiUrl).getResponseCode() == 200) {
+            return clientId;
+        }
 
+        final DownloadResponse download = dl.get("https://soundcloud.com");
+        String response = download.getResponseBody();
         final String clientIdPattern = ",client_id:\"(.*?)\"";
 
-        try {
-            final HashMap<String, String> headers = new HashMap<>();
-            headers.put("Range", "bytes=0-16384");
-            String js = dl.download(jsElement.attr("src"), headers);
-
-            return clientId = Parser.matchGroup1(clientIdPattern, js);
-        } catch (IOException | RegexException ignored) {
-            // Ignore it and proceed to download the whole js file
+        Document doc = Jsoup.parse(response);
+        final Elements possibleScripts = doc.select("script[src*=\"sndcdn.com/assets/\"][src$=\".js\"]");
+        // The one containing the client id will likely be the last one
+        Collections.reverse(possibleScripts);
+
+        final HashMap<String, String> headers = new HashMap<>();
+        headers.put("Range", "bytes=0-16384");
+
+        for (Element element : possibleScripts) {
+            final String srcUrl = element.attr("src");
+            if (srcUrl != null && !srcUrl.isEmpty()) {
+                try {
+                    return clientId = Parser.matchGroup1(clientIdPattern, dl.download(srcUrl, headers));
+                } catch (RegexException ignored) {
+                    // Ignore it and proceed to try searching other script
+                }
+            }
         }
 
-        String js = dl.download(jsElement.attr("src"));
-        return clientId = Parser.matchGroup1(clientIdPattern, js);
+        // Officially give up
+        throw new ExtractionException("Couldn't extract client id");
     }
 
     public static String toDateString(String time) throws ParsingException {
@@ -79,7 +97,7 @@ public static String toDateString(String time) throws ParsingException {
      * 
      * See https://developers.soundcloud.com/docs/api/reference#resolve
      */
-    public static JsonObject resolveFor(Downloader downloader, String url) throws IOException, ReCaptchaException, ParsingException {
+    public static JsonObject resolveFor(Downloader downloader, String url) throws IOException, ExtractionException {
         String apiUrl = "https://api.soundcloud.com/resolve"
                 + "?url=" + URLEncoder.encode(url, "UTF-8")
                 + "&client_id=" + clientId();

extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudSearchQueryHandlerFactory.java

@@ -1,5 +1,6 @@
 package org.schabi.newpipe.extractor.services.soundcloud;
 
+import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.exceptions.ReCaptchaException;
 import org.schabi.newpipe.extractor.linkhandler.SearchQueryHandlerFactory;
@@ -48,10 +49,10 @@ public String getUrl(String id, List<String> contentFilter, String sortFilter) t
 
         } catch (UnsupportedEncodingException e) {
             throw new ParsingException("Could not encode query", e);
-        } catch (IOException e) {
-            throw new ParsingException("Could not get client id", e);
         } catch (ReCaptchaException e) {
             throw new ParsingException("ReCaptcha required", e);
+        } catch (IOException | ExtractionException e) {
+            throw new ParsingException("Could not get client id", e);
         }
     }