398467 Servlet 3.1 Non Blocking IO

Improved sendContent API and javadoc. Added FastFileServer example

examples/embedded/src/main/java/org/eclipse/jetty/embedded/FastFileServer.java

@@ -0,0 +1,181 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.embedded;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileChannel.MapMode;
+import java.nio.file.StandardOpenOption;
+
+import javax.servlet.AsyncContext;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.eclipse.jetty.http.MimeTypes;
+import org.eclipse.jetty.server.Handler;
+import org.eclipse.jetty.server.HttpOutput;
+import org.eclipse.jetty.server.Request;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.handler.AbstractHandler;
+import org.eclipse.jetty.server.handler.DefaultHandler;
+import org.eclipse.jetty.server.handler.HandlerList;
+import org.eclipse.jetty.server.handler.ResourceHandler;
+import org.eclipse.jetty.servlet.DefaultServlet;
+import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.URIUtil;
+import org.eclipse.jetty.util.resource.Resource;
+
+/* ------------------------------------------------------------ */
+/** Fast FileServer.
+ * 
+ * <p>This example shows how to use the Jetty APIs for sending static
+ * as fast as possible  using various strategies for small, medium and 
+ * large content.</p>
+ * <p>The Jetty {@link DefaultServlet} does all this and more, and to 
+ * a lesser extent so does the {@link ResourceHandler}, so unless you
+ * have exceptional circumstances it is best to use those classes for
+ * static content</p>
+ */
+public class FastFileServer
+{
+    public static void main(String[] args) throws Exception
+    {
+        Server server = new Server(8080);
+                
+        HandlerList handlers = new HandlerList();
+        handlers.setHandlers(new Handler[] { new FastFileHandler(new File(".")), new DefaultHandler() });
+        server.setHandler(handlers);
+
+        server.start();
+        server.join();
+    }
+
+    static class FastFileHandler extends AbstractHandler
+    {
+        private final MimeTypes _mimeTypes = new MimeTypes();
+        private final File _dir;
+        
+        FastFileHandler(File dir)
+        {
+            _dir=dir;
+        }
+        
+        @Override
+        public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
+        {
+            // define small medium and large.  
+            // This should be turned for your content, JVM and OS, but we will huge HTTP response buffer size as a measure
+            final int SMALL=response.getBufferSize();
+            final int MEDIUM=8*SMALL;
+            
+            
+            // What file to serve?
+            final File file = new File(_dir,request.getPathInfo());
+            
+            // Only handle existing files
+            if (!file.exists())
+                return;
+
+            // we will handle this request
+            baseRequest.setHandled(true);
+            
+            // Handle directories
+            if (file.isDirectory())
+            {
+                if (!request.getPathInfo().endsWith(URIUtil.SLASH))
+                {
+                    response.sendRedirect(response.encodeRedirectURL(URIUtil.addPaths(request.getRequestURI(),URIUtil.SLASH)));
+                    return;
+                }
+                String listing = Resource.newResource(file).getListHTML(request.getRequestURI(),request.getPathInfo().lastIndexOf("/") > 0);
+                response.setContentType("text/html; charset=UTF-8");
+                response.getWriter().println(listing);
+                return;
+            }
+            
+            // Set some content headers
+            // Jetty DefaultServlet will cache formatted date strings, but we will reformat for each request here
+            response.setDateHeader("Last-Modified",file.lastModified());
+            response.setDateHeader("Content-Length",file.length());
+            response.setContentType(_mimeTypes.getMimeByExtension(file.getName()));
+            
+            
+            
+            // send "small" files blocking directly from an input stream
+            if (file.length()<SMALL)
+            {
+                // need to caste to Jetty output stream for best API
+                ((HttpOutput)response.getOutputStream()).sendContent(FileChannel.open(file.toPath(),StandardOpenOption.READ));
+                return;
+            }
+            
+            
+            // send not "small" files asynchronously so we don't hold threads if the client is slow
+            final AsyncContext async = request.startAsync();
+            Callback completionCB = new Callback()
+            {
+                @Override
+                public void succeeded()
+                {
+                    // Async content write succeeded, so complete async response
+                    async.complete();
+                }
+
+                @Override
+                public void failed(Throwable x)
+                {
+                    // log error and complete async response;
+                    x.printStackTrace();
+                    async.complete();
+                }
+            };
+            
+            
+            
+            // send "medium" files from an input stream
+            if (file.length()<MEDIUM)
+            {
+                ((HttpOutput)response.getOutputStream()).sendContent(FileChannel.open(file.toPath(),StandardOpenOption.READ),completionCB);
+                return;
+            }
+            
+            
+            // for "large" files get the file mapped buffer to send
+            // Typically the resulting buffer should be cached as allocating kernel memory
+            // can be hard to GC on some JVMs.   But for this example we will create a new buffer per file
+            ByteBuffer buffer;
+            try (RandomAccessFile raf = new RandomAccessFile(file,"r");)
+            {
+                buffer=raf.getChannel().map(MapMode.READ_ONLY,0,raf.length());
+            }
+            
+            // Assuming the file buffer might be shared cached version, so lets take our own view of it
+            buffer=buffer.asReadOnlyBuffer();
+            
+
+            // send the content as a buffer with a callback to complete the async request
+            // need to caste to Jetty output stream for best API
+            ((HttpOutput)response.getOutputStream()).sendContent(buffer,completionCB);
+        }   
+    }
+}

jetty-server/src/main/java/org/eclipse/jetty/server/HttpOutput.java

@@ -231,6 +231,12 @@ public class HttpOutput extends ServletOutputStream
         write(s.getBytes(_channel.getResponse().getCharacterEncoding()));
     }
 
+    /* ------------------------------------------------------------ */
+    /** Set headers and send content.
+     * @deprecated Use {@link Response#setHeaders(HttpContent)} and {@link #sendContent(HttpContent)} instead.
+     * @param content
+     * @throws IOException
+     */
     @Deprecated
     public void sendContent(Object content) throws IOException
     {
@@ -277,7 +283,69 @@ public class HttpOutput extends ServletOutputStream
         }
     }
 
+    /* ------------------------------------------------------------ */
+    /** Blocking send of content.
+     * @param content The content to send
+     * @throws IOException
+     */
+    public void sendContent(ByteBuffer content) throws IOException
+    {
+        try
+        {
+            final BlockingCallback callback =_channel.getWriteBlockingCallback();
+            _channel.write(content,true,callback);
+            callback.block();
+        }
+        catch (InterruptedException | TimeoutException e)
+        {
+            throw new IOException(e);
+        }
+    }
 
+    /* ------------------------------------------------------------ */
+    /** Blocking send of content.
+     * @param content The content to send
+     * @throws IOException
+     */
+    public void sendContent(InputStream in) throws IOException
+    {
+        try
+        {
+            final BlockingCallback callback =_channel.getWriteBlockingCallback();
+            new InputStreamWritingCB(in,callback).iterate();
+            callback.block();
+        }
+        catch (InterruptedException | TimeoutException e)
+        {
+            throw new IOException(e);
+        }
+    }
+
+    /* ------------------------------------------------------------ */
+    /** Blocking send of content.
+     * @param content The content to send
+     * @throws IOException
+     */
+    public void sendContent(ReadableByteChannel in) throws IOException
+    {
+        try
+        {
+            final BlockingCallback callback =_channel.getWriteBlockingCallback();
+            new ReadableByteChannelWritingCB(in,callback).iterate();
+            callback.block();
+        }
+        catch (InterruptedException | TimeoutException e)
+        {
+            throw new IOException(e);
+        }
+    }
+    
+
+    /* ------------------------------------------------------------ */
+    /** Blocking send of content.
+     * @param content The content to send
+     * @throws IOException
+     */
     public void sendContent(HttpContent content) throws IOException
     {
         try
@@ -292,21 +360,42 @@ public class HttpOutput extends ServletOutputStream
         }
     }
    
+
+    /* ------------------------------------------------------------ */
+    /** Asynchronous send of content.
+     * @param content The content to send
+     * @param callback The callback to use to notify success or failure
+     */
     public void sendContent(ByteBuffer content, Callback callback)
     {
         _channel.write(content,true,callback);
     }
 
+    /* ------------------------------------------------------------ */
+    /** Asynchronous send of content.
+     * @param content The content to send
+     * @param callback The callback to use to notify success or failure
+     */
     public void sendContent(InputStream in, Callback callback)
     {
         new InputStreamWritingCB(in,callback).iterate();
     }
 
+    /* ------------------------------------------------------------ */
+    /** Asynchronous send of content.
+     * @param content The content to send
+     * @param callback The callback to use to notify success or failure
+     */
     public void sendContent(ReadableByteChannel in, Callback callback)
     {
         new ReadableByteChannelWritingCB(in,callback).iterate();
     }
 
+    /* ------------------------------------------------------------ */
+    /** Asynchronous send of content.
+     * @param content The content to send
+     * @param callback The callback to use to notify success or failure
+     */
     public void sendContent(HttpContent httpContent, Callback callback) throws IOException
     {
         if (isClosed())
@@ -361,6 +450,15 @@ public class HttpOutput extends ServletOutputStream
             BufferUtil.clear(_aggregate);
     }
     
+    
+    /* ------------------------------------------------------------ */
+    /** An iterating callback that will take content from an 
+     * InputStream and write it to the associated {@link HttpChannel}.
+     * A non direct buffer of size {@link HttpOutput#getBufferSize()} is used. 
+     * This callback is passed to the {@link HttpChannel#write(ByteBuffer, boolean, Callback)} to
+     * be notified as each buffer is written and only once all the input is consumed will the 
+     * wrapped {@link Callback#succeeded()} method be called. 
+     */
     private class InputStreamWritingCB extends IteratingCallback
     {
         final InputStream _in;
@@ -409,6 +507,15 @@ public class HttpOutput extends ServletOutputStream
         
     }
 
+    /* ------------------------------------------------------------ */
+    /** An iterating callback that will take content from a 
+     * ReadableByteChannel and write it to the {@link HttpChannel}.
+     * A {@link ByteBuffer} of size {@link HttpOutput#getBufferSize()} is used that will be direct if
+     * {@link HttpChannel#useDirectBuffers()} is true.
+     * This callback is passed to the {@link HttpChannel#write(ByteBuffer, boolean, Callback)} to
+     * be notified as each buffer is written and only once all the input is consumed will the 
+     * wrapped {@link Callback#succeeded()} method be called. 
+     */
     private class ReadableByteChannelWritingCB extends IteratingCallback
     {
         final ReadableByteChannel _in;
@@ -456,6 +563,5 @@ public class HttpOutput extends ServletOutputStream
             super.failed(x);
             _channel.getByteBufferPool().release(_buffer);
         }
-        
     }
 }

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ResourceHandler.java

@@ -22,6 +22,7 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.net.MalformedURLException;
 
+import javax.servlet.AsyncContext;
 import javax.servlet.RequestDispatcher;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
@@ -37,6 +38,7 @@ import org.eclipse.jetty.server.HttpOutput;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Response;
 import org.eclipse.jetty.server.handler.ContextHandler.Context;
+import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.URIUtil;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;
@@ -438,22 +440,34 @@ public class ResourceHandler extends HandlerWrapper
         if(skipContentBody)
             return;
         
-        
         // Send the content
         OutputStream out =null;
         try {out = response.getOutputStream();}
         catch(IllegalStateException e) {out = new WriterOutputStream(response.getWriter());}
 
-       
-        if (out instanceof HttpOutput)
-        {
-            ((HttpOutput)out).sendContent(resource);
-        }
-        else
-        {
         if (last_modified>0)
             response.setDateHeader(HttpHeader.LAST_MODIFIED.asString(),last_modified);
        
+        if (out instanceof HttpOutput && request.isAsyncSupported())
+        {
+            final AsyncContext async = request.startAsync();
+            ((HttpOutput)out).sendContent(resource.getReadableByteChannel(),new Callback()
+            {
+                @Override
+                public void succeeded()
+                {
+                    async.complete();
+                }
+
+                @Override
+                public void failed(Throwable x)
+                {
+                    async.complete();
+                }   
+            });
+        }
+        else
+        {
             // Write content normally
             resource.writeTo(out,0,resource.length());
         }

jetty-util/src/main/java/org/eclipse/jetty/util/BufferUtil.java

@@ -731,9 +731,10 @@ public class BufferUtil
 
     public static ByteBuffer toBuffer(File file) throws IOException
     {
-        RandomAccessFile raf = new RandomAccessFile(file,"r");
+        try(RandomAccessFile raf = new RandomAccessFile(file,"r");)
-        MappedByteBuffer buffer=raf.getChannel().map(MapMode.READ_ONLY,0,raf.length());
+        {
-        return buffer;
+            return raf.getChannel().map(MapMode.READ_ONLY,0,raf.length());
+        }
     }
 
     public static String toSummaryString(ByteBuffer buffer)