resourcedownloaderurlimpl.java

这是一个基于java编写的torrent的P2P源码

	}

	public InputStream
	download()
	
		throws ResourceDownloaderException
	{
		// System.out.println("ResourceDownloader:download - " + getName());
		
		try{
			reportActivity(this, getLogIndent() + "Downloading: " + original_url );
			
			try{
				this_mon.enter();
				
				if ( download_initiated ){
					
					throw( new ResourceDownloaderException("Download already initiated"));
				}
				
				download_initiated	= true;
				
			}finally{
				
				this_mon.exit();
			}
			
			try{
				URL	url = new URL( original_url.toString().replaceAll( " ", "%20" ));
			      
					// some authentications screw up without an explicit port number here
				
				String	protocol = url.getProtocol().toLowerCase();
				
				if ( url.getPort() == -1 && !protocol.equals( "magnet" )){
					
					int	target_port;
					
					if ( protocol.equals( "http" )){
						
						target_port = 80;
						
					}else{
						
						target_port = 443;
					}
					
					try{
						String str = original_url.toString().replaceAll( " ", "%20" );
					
						int	pos = str.indexOf( "://" );
						
						pos = str.indexOf( "/", pos+4 );
						
							// might not have a trailing "/"
						
						if ( pos == -1 ){
							
							url = new URL( str + ":" + target_port + "/" );
							
						}else{
						
							url = new URL( str.substring(0,pos) + ":" + target_port + str.substring(pos));
						}
												
					}catch( Throwable e ){
						
						Debug.printStackTrace( e );
					}
				}
				
				url = AddressUtils.adjustURL( url );
				
				try{
					if ( auth_supplied ){
						
						SESecurityManager.addPasswordHandler( url, this );
					}

					for (int i=0;i<2;i++){
						
						try{
							HttpURLConnection	con;
							
							if ( url.getProtocol().equalsIgnoreCase("https")){
						      	
									// see ConfigurationChecker for SSL client defaults
				
								HttpsURLConnection ssl_con = (HttpsURLConnection)url.openConnection();
				
									// allow for certs that contain IP addresses rather than dns names
				  	
								ssl_con.setHostnameVerifier(
										new HostnameVerifier()
										{
											public boolean
											verify(
													String		host,
													SSLSession	session )
											{
												return( true );
											}
										});
				  	
								con = ssl_con;
				  	
							}else{
				  	
								con = (HttpURLConnection) url.openConnection();
				  	
							}
							
							con.setRequestProperty("User-Agent", Constants.AZUREUS_NAME + " " + Constants.AZUREUS_VERSION);     
				  
					 		con.setRequestProperty( "Connection", "close" );

							con.addRequestProperty( "Accept-Encoding", "gzip" );
							 
							if (postData != null) {
								con.setDoOutput(true);
								con.setRequestMethod("POST");
								OutputStreamWriter wr = new OutputStreamWriter(con.getOutputStream());
								wr.write(postData);
								wr.flush();
							}

							con.connect();
				
							int response = con.getResponseCode();
												
							if ((response != HttpURLConnection.HTTP_ACCEPTED) && (response != HttpURLConnection.HTTP_OK)) {
								
								throw( new ResourceDownloaderException("Error on connect for '" + url.toString() + "': " + Integer.toString(response) + " " + con.getResponseMessage()));    
							}
								
							boolean gzip = false;
							try{
								this_mon.enter();
								
								input_stream = con.getInputStream();
								
								String encoding = con.getHeaderField( "content-encoding");
				 				
				 				gzip = encoding != null && encoding.equalsIgnoreCase("gzip");
				 								 				
				 				if ( gzip ){
				 									 					
				 					input_stream = new GZIPInputStream( input_stream );
				 				}
							}finally{
								
								this_mon.exit();
							}
							
							ByteArrayOutputStream	baos;
			
							try{
								byte[] buf = new byte[BUFFER_SIZE];
								
								int	total_read	= 0;
								
									// unfortunately not all servers set content length
								
								/* From Apache's mod_deflate doc:
								 * http://httpd.apache.org/docs/2.0/mod/mod_deflate.html
										Note on Content-Length

										If you evaluate the request body yourself, don't trust the
										Content-Length header! The Content-Length header reflects 
										the length of the incoming data from the client and not the
										byte count of the decompressed data stream.
								 */
								int size = gzip ? -1 : con.getContentLength();					
								
								baos = size>0?new ByteArrayOutputStream(size):new ByteArrayOutputStream();
								
								while( !cancel_download ){
									
									int read = input_stream.read(buf);
										
									if ( read > 0 ){
										
										baos.write(buf, 0, read);
										
										total_read += read;
								        
										if ( size > 0){
											
											informPercentDone(( 100 * total_read ) / size );
										}
									}else{
										
										break;
									}
								}
								
									// if we've got a size, make sure we've read all of it
								
								if ( size > 0 && total_read != size ){
									
									if ( total_read > size ){
										
											// this has been seen with UPnP linksys - more data is read than
											// the content-length has us believe is coming (1 byte in fact...)
										
										Debug.out( "Inconsistent stream length for '" + original_url + "': expected = " + size + ", actual = " + total_read );
										
									}else{
										
										throw( new IOException( "Premature end of stream" ));
									}
								}
							}finally{
								
								input_stream.close();
							}
				
							InputStream	res = new ByteArrayInputStream( baos.toByteArray());
							
							if ( informComplete( res )){
							
								return( res );
							}
							
							throw( new ResourceDownloaderException("Contents downloaded but rejected: '" + original_url + "'" ));
	
						}catch( SSLException e ){
							
							if ( i == 0 ){
								
								if ( SESecurityManager.installServerCertificates( url ) != null ){
									
										// certificate has been installed
									
									continue;	// retry with new certificate
								}
							}

							throw( e );							
						}
					}
					
					throw( new ResourceDownloaderException("Should never get here" ));
					
				}finally{
							
					if ( auth_supplied ){
								
						SESecurityManager.removePasswordHandler( url, this );
					}
				}
			}catch (java.net.MalformedURLException e){
				
				throw( new ResourceDownloaderException("Exception while parsing URL '" + original_url + "':" + e.getMessage(), e));
				
			}catch (java.net.UnknownHostException e){
				
				throw( new ResourceDownloaderException("Exception while initializing download of '" + original_url + "': Unknown Host '" + e.getMessage() + "'", e));
				
			}catch (java.io.IOException e ){
				
				throw( new ResourceDownloaderException("I/O Exception while downloading '" + original_url + "':" + e.toString(), e ));
			}
		}catch( Throwable e ){
			
			ResourceDownloaderException	rde;
			
			if ( e instanceof ResourceDownloaderException ){
				
				rde = (ResourceDownloaderException)e;
				
			}else{
				
				rde = new ResourceDownloaderException( "Unexpected error", e );
			}
			
			informFailed(rde);
			
			throw( rde );
		}
	}
	
	public void
	cancel()
	{
		setCancelled();
		
		cancel_download	= true;
		
		try{
			this_mon.enter();
			
			if ( input_stream != null ){
				
				try{
					input_stream.close();
					
				}catch( Throwable e ){
					
				}
			}
		}finally{
			
			this_mon.exit();
		}
		
		informFailed( new ResourceDownloaderException( "Download cancelled" ));
	}
	
	public PasswordAuthentication
	getAuthentication(
		String		realm,
		URL			tracker )
	{
		if ( user_name == null || password == null ){
			
			String user_info = tracker.getUserInfo();
			
			if ( user_info == null ){
				
				return( null );
			}
			
			String	user_bit	= user_info;
			String	pw_bit		= "";
			
			int	pos = user_info.indexOf(':');
			
			if ( pos != -1 ){
				
				user_bit	= user_info.substring(0,pos);
				pw_bit		= user_info.substring(pos+1);
			}
			
			return( new PasswordAuthentication( user_bit, pw_bit.toCharArray()));
		}
		
		return( new PasswordAuthentication( user_name, password.toCharArray()));
	}
	
	public void
	setAuthenticationOutcome(
		String		realm,
		URL			tracker,
		boolean		success )
	{
	}
	
	public void
	clearPasswords()
	{
	}
}