playlistparser.java

来自「java语言开发的P2P流媒体系统」· Java 代码 · 共 234 行

/* 
 * P2P-Radio - Peer to peer streaming system
 * Project homepage: http://p2p-radio.sourceforge.net/
 * Copyright (C) 2003-2004 Michael Kaufmann <[e-mail]>
 * 
 * ---------------------------------------------------------------------------
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * ---------------------------------------------------------------------------
 */

package p2pradio.sources;

import java.io.*;
import java.net.*;
import java.util.*;


/**
 * Parses a Playlist (PLS or M3U) and returns all URLs that are contained in it.
 * 
 * @author Michael Kaufmann
 */
public class PlaylistParser
{
	public static final Set PLS_MIME_TYPES;
	public static final Set M3U_MIME_TYPES;
	
	static
	{
		PLS_MIME_TYPES = new HashSet();
		M3U_MIME_TYPES = new HashSet();
		
		// You should use these MIME types:
		PLS_MIME_TYPES.add("audio/x-scpls"); //$NON-NLS-1$
		M3U_MIME_TYPES.add("audio/x-mpegurl"); //$NON-NLS-1$
		
		// Please don't use these MIME types:
		PLS_MIME_TYPES.add("audio/scpls"); //$NON-NLS-1$
		M3U_MIME_TYPES.add("audio/mpegurl"); //$NON-NLS-1$
		M3U_MIME_TYPES.add("audio/m3u"); //$NON-NLS-1$
		M3U_MIME_TYPES.add("audio/x-m3u"); //$NON-NLS-1$
	}
	
	private PlaylistParser()
	{
		// Keine Instanzen
	}
	
	// Soviele Zeilen darf die Playlist maximal haben
	public static final int MAX_LINES = 100;
	
	public static boolean isPlaylistMIMEType(String mimeType)
	{
		String mimeTypeLowerCase = mimeType.toLowerCase();
		
		return (PLS_MIME_TYPES.contains(mimeTypeLowerCase) || M3U_MIME_TYPES.contains(mimeTypeLowerCase));
	}
	
	/**
	 * Parses the Playlist at location <code>playlistURL</code>
	 * and returns all URLs that are contained in it.
	 */
	public static URL[] parse(URL playlistURL)
	{
		InputStream inputStream = null;
				
		try
		{
			URLConnection connection = playlistURL.openConnection();
			connection.setAllowUserInteraction(false);
			connection.setUseCaches(false);
			connection.connect();
			
			inputStream = connection.getInputStream();
		
			String contentType = connection.getContentType();
			
			boolean couldBePLS;
			boolean couldBeM3U;
			
			if (contentType == null)
			{
				couldBePLS = true;
				couldBeM3U = true;
			}
			else
			{
				String contentTypeLowerCase = contentType.toLowerCase();
				
				couldBePLS = PLS_MIME_TYPES.contains(contentTypeLowerCase);
				couldBeM3U = M3U_MIME_TYPES.contains(contentTypeLowerCase);
			}
			
			if (!couldBePLS && !couldBeM3U)
			{
				// Das ist keine Playlist, sondern etwas anderes
				return null;
			}
		 
			Vector URLs = new Vector();
		
			BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
		
			for (int i=0; i < MAX_LINES; i++)
			{	
				String line = null;
			
				try
				{
					line = reader.readLine();
				}
				catch (IOException e)
				{
					// Mit dem Zeilenlesen aufh鰎en
					break;
				}
			
				if (line == null)
				{
					// Mit dem Zeilenlesen aufh鰎en
					break;
				}
				
				line = line.trim();
				
				if (couldBePLS)
				{
					if (line.toLowerCase().startsWith("file")) //$NON-NLS-1$
					{
						int equalSignPos = line.indexOf('=');
						
						if (equalSignPos != -1)
						{
							// Ein Gleichheitszeichen ist da
								
							// Ist das X bei "FileX=..." eine Zahl?
							String shouldBeANumber = line.substring(4, equalSignPos);
							
							boolean isANumber = true;
			
							try
							{
								Integer.parseInt(shouldBeANumber);
							}
							catch (NumberFormatException e)
							{
								isANumber = false;
							}
							
							if (isANumber)
							{
								// Jetzt kann der Rest der Zeile als URL behandelt werden
								String URLString = line.substring(equalSignPos+1, line.length());
								
								// Nur HTTP-URLs akzeptieren
								if (URLString.toLowerCase().startsWith(("http://"))) //$NON-NLS-1$
								{
									try
									{
										URLs.add(new URL(URLString));
										
										// Mit der n鋍hsten Zeile weitermachen
										continue;
									}
									catch (MalformedURLException e)
									{
									}
								}
							}
						}
					}
				}
				
				if (couldBeM3U)
				{
					if (line.toLowerCase().startsWith("http://")) //$NON-NLS-1$
					{
						try
						{
							URLs.add(new URL(line));
									
							// Mit der n鋍hsten Zeile weitermachen
							continue;
						}
						catch (MalformedURLException e)
						{
						}
					}
				}				
			}
		
			// Object-Array in ein URL-Array konvertieren
			Object[] objectArray = URLs.toArray();
			URL[] URLArray = new URL[objectArray.length];
		
			for (int i=0; i < URLArray.length; i++)
			{
				URLArray[i] = (URL)objectArray[i];
			}
		
			return URLArray;		
		}
		catch (IOException e)
		{
			return null;
		}
		finally
		{
			if (inputStream != null)
			{
				try
				{
					inputStream.close();
				}
				catch (IOException e)
				{
				}
			}
		}
	}
}