bug fixes; code style improvements;

src/main/java/com/github/kiulian/downloader/YoutubeDownloadCallback.java

@@ -0,0 +1,12 @@
+package com.github.kiulian.downloader;
+
+import java.io.File;
+
+public interface YoutubeDownloadCallback {
+
+    void onDownloading(int progress);
+
+    void onFinished(File file);
+
+    void onError(Throwable throwable);
+}

src/main/java/com/github/kiulian/downloader/YoutubeDownloader.java

@@ -9,9 +9,9 @@
  * 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.
@@ -33,13 +33,16 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
 import java.net.URL;
 import java.net.URLConnection;
 import java.util.ArrayList;
 import java.util.List;
 
 public class YoutubeDownloader {
 
+    public static final char[] ILLEGAL_FILENAME_CHARACTERS = {'/', '\n', '\r', '\t', '\0', '\f', '`', '?', '*', '\\', '<', '>', '|', '\"', ':'};
+
     public interface DownloadCallback {
 
         void onDownloading(int progress);
@@ -49,8 +52,11 @@ public interface DownloadCallback {
         void onError(Throwable throwable);
     }
 
+    private static final String AUDIO = "audio";
+    private static final String VIDEO = "video";
     private static final String CONFIG_START = "ytplayer.config = ";
     private static final String CONFIG_END = ";ytplayer.load";
+    private static final String ERROR = "\"status\":\"ERROR\",\"reason\":\"";
 
 
     public static YoutubeVideo getVideo(String videoId) throws YoutubeException, IOException {
@@ -61,6 +67,15 @@ public static YoutubeVideo getVideo(String videoId) throws YoutubeException, IOE
         int start = page.indexOf(CONFIG_START);
         int end = page.indexOf(CONFIG_END);
 
+        if (start == -1 || end == -1) {
+            int errorIndex = page.indexOf(ERROR);
+            if (errorIndex != -1) {
+                String reason = page.substring(errorIndex + ERROR.length(), page.indexOf("\"", errorIndex + ERROR.length() + 1));
+                throw new YoutubeException.VideoUnavailableException(reason);
+            } else {
+                throw new YoutubeException.BadPageException("Could not parse web page");
+            }
+        }
         String cfg = page.substring(start + CONFIG_START.length(), end);
 
         JSONObject object;
@@ -74,8 +89,8 @@ public static YoutubeVideo getVideo(String videoId) throws YoutubeException, IOE
             throw new YoutubeException.BadPageException("Could not parse web page");
         }
 
-        JSONArray jsonFormats = object.getJSONArray("formats");
-        JSONArray jsonAdaptiveFormats = object.getJSONArray("adaptiveFormats");
+        JSONArray jsonFormats = object.containsKey("formats") ? object.getJSONArray("formats") : new JSONArray();
+        JSONArray jsonAdaptiveFormats = object.containsKey("adaptiveFormats") ? object.getJSONArray("adaptiveFormats") : new JSONArray();
 
         List<Format> formats = new ArrayList<>(jsonAdaptiveFormats.size() + jsonFormats.size());
         int i;
@@ -91,11 +106,11 @@ public static YoutubeVideo getVideo(String videoId) throws YoutubeException, IOE
             try {
                 JSONObject json = jsonAdaptiveFormats.getJSONObject(i);
                 String mimeType = json.getString("mimeType");
-                if (mimeType.contains(Constants.AUDIO))
+                if (mimeType.contains(AUDIO))
                     formats.add(new AudioFormat(json));
-                else if (mimeType.contains(Constants.VIDEO))
+                else if (mimeType.contains(VIDEO))
                     formats.add(new VideoFormat(json));
-            } catch (NullPointerException e) {
+            } catch (Exception e) {
                 e.printStackTrace();
             }
         }
@@ -104,7 +119,10 @@ else if (mimeType.contains(Constants.VIDEO))
     }
 
     private static String loadPage(String url) throws IOException {
-        URLConnection connection = new URL(url).openConnection();
+        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
+        connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36");
+        connection.setRequestProperty("Accept-Language", "en-US,en;");
+
         BufferedReader in = new BufferedReader(new InputStreamReader(
                 connection.getInputStream()));
 

src/main/java/com/github/kiulian/downloader/YoutubeException.java

@@ -9,9 +9,9 @@
  * 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.
@@ -21,7 +21,7 @@
  */
 
 public class YoutubeException extends Exception {
-    public YoutubeException(String message) {
+    private YoutubeException(String message) {
         super(message);
     }
 
@@ -47,5 +47,11 @@ public FormatNotFoundException(String message) {
 
     }
 
+    public static class LiveVideoException extends YoutubeException {
+
+        public LiveVideoException(String message) {
+            super(message);
+        }
 
+    }
 }

src/main/java/com/github/kiulian/downloader/model/Extension.java

@@ -0,0 +1,22 @@
+package com.github.kiulian.downloader.model;
+
+public class Extension {
+
+    public static final Extension MP4 = new Extension("mp4");
+    public static final Extension WEBM = new Extension("webm");
+    public static final Extension THREEGP = new Extension("3gp");
+    public static final Extension FLV = new Extension("flv");
+    public static final Extension HLS = new Extension("hls");
+    public static final Extension M4A = new Extension("m4a");
+    public static final Extension UNKNOWN = new Extension("unknown");
+
+    private final String value;
+
+    private Extension(String value) {
+        this.value = value;
+    }
+
+    public String value() {
+        return value;
+    }
+}

src/main/java/com/github/kiulian/downloader/model/VideoDetails.java

@@ -9,9 +9,9 @@
  * 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.
@@ -24,6 +24,7 @@
 import com.alibaba.fastjson.JSONObject;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 public class VideoDetails {
@@ -47,7 +48,7 @@ public VideoDetails(String videoId) {
     public void setDetails(JSONObject json) {
         title = json.getString("title");
         lengthSeconds = json.getInteger("lengthSeconds");
-        keywords = json.getJSONArray("keywords").toJavaList(String.class);
+        keywords = json.containsKey("keywords") ? json.getJSONArray("keywords").toJavaList(String.class) : Collections.emptyList();
         shortDescription = json.getString("shortDescription");
         JSONArray jsonThumbnails = json.getJSONObject("thumbnail").getJSONArray("thumbnails");
         thumbnails = new ArrayList<>(jsonThumbnails.size());
@@ -78,7 +79,7 @@ public List<String> keywords() {
         return keywords;
     }
 
-    public String shortDescription() {
+    public String description() {
         return shortDescription;
     }
 
@@ -94,11 +95,11 @@ public int viewCount() {
         return viewCount;
     }
 
-    public int getAverageRating() {
+    public int averageRating() {
         return averageRating;
     }
 
-    public boolean liveContent() {
+    public boolean isLive() {
         return isLiveContent;
     }
 }