Implemented a TryFilesFilter inspired by nginx's try_files directive.

This is needed by - for example - WordPress because it allows for
different permalinks schemes.
For example, /foo could be a permalink that should be directed to
PHP, while /favicon.ico is a file that must be served statically.
URI /foo would be matched by the default servlet resulting in a 404.
Therefore we need a filter mapped to /* that checks whether the
request URI is a file that exists and likely to be served by the
default servlet, otherwise it needs to rewrite the URL to something
like /index.php?p=/foo.
The rewrite filter does not have the functionality of "try the file,
if missing then rewrite" that is now implemented by the TryFilesFilter.

fcgi-proxy/src/main/java/org/eclipse/jetty/fcgi/proxy/TryFilesFilter.java

@@ -0,0 +1,109 @@
+//
+//  ========================================================================
+//  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.fcgi.proxy;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Inspired by nginx's try_files functionality
+ */
+public class TryFilesFilter implements Filter
+{
+    public static final String ROOT_INIT_PARAM = "root";
+    public static final String FILES_INIT_PARAM = "files";
+
+    private String root;
+    private String[] files;
+
+    @Override
+    public void init(FilterConfig config) throws ServletException
+    {
+        root = config.getInitParameter(ROOT_INIT_PARAM);
+        if (root == null)
+            throw new ServletException(String.format("Missing mandatory parameter '%s'", ROOT_INIT_PARAM));
+        String param = config.getInitParameter(FILES_INIT_PARAM);
+        if (param == null)
+            throw new ServletException(String.format("Missing mandatory parameter '%s'", FILES_INIT_PARAM));
+        files = param.split(" ");
+    }
+
+    public String getRoot()
+    {
+        return root;
+    }
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
+    {
+        HttpServletRequest httpRequest = (HttpServletRequest)request;
+        HttpServletResponse httpResponse = (HttpServletResponse)response;
+
+        for (int i = 0; i < files.length - 1; ++i)
+        {
+            String file = files[i];
+            String resolved = resolve(httpRequest, file);
+            Path path = Paths.get(getRoot(), resolved);
+            if (Files.exists(path) && Files.isReadable(path))
+            {
+                chain.doFilter(httpRequest, httpResponse);
+                return;
+            }
+        }
+
+        // The last one is the fallback
+        fallback(httpRequest, httpResponse, chain, files[files.length - 1]);
+    }
+
+    protected void fallback(HttpServletRequest request, HttpServletResponse response, FilterChain chain, String fallback) throws IOException, ServletException
+    {
+        String resolved = resolve(request, fallback);
+        request.getRequestDispatcher(resolved).forward(request, response);
+    }
+
+    private String resolve(HttpServletRequest request, String value)
+    {
+        String path = request.getRequestURI();
+        String query = request.getQueryString();
+
+        String result = value.replaceAll("\\$path", path);
+        result = result.replaceAll("\\$query", query == null ? "" : query);
+
+        // Remove the "?" or "&" at the end if there is no query
+        if (query == null && (result.endsWith("?") || result.endsWith("&")))
+            result = result.substring(0, result.length() - 1);
+
+        return result;
+    }
+
+    @Override
+    public void destroy()
+    {
+    }
+}

fcgi-proxy/src/test/java/org/eclipse/jetty/fcgi/proxy/WordPressSPDYFastCGIProxyServer.java

@@ -0,0 +1,86 @@
+//
+//  ========================================================================
+//  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.fcgi.proxy;
+
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Map;
+import javax.servlet.DispatcherType;
+
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.servlet.DefaultServlet;
+import org.eclipse.jetty.servlet.FilterHolder;
+import org.eclipse.jetty.servlet.ServletContextHandler;
+import org.eclipse.jetty.servlet.ServletHolder;
+import org.eclipse.jetty.spdy.api.SPDY;
+import org.eclipse.jetty.spdy.server.http.HTTPSPDYServerConnector;
+import org.eclipse.jetty.spdy.server.http.PushStrategy;
+import org.eclipse.jetty.spdy.server.http.ReferrerPushStrategy;
+import org.eclipse.jetty.util.ssl.SslContextFactory;
+
+public class WordPressSPDYFastCGIProxyServer
+{
+    public static void main(String[] args) throws Exception
+    {
+//        int port = 8080;
+        int port = 8443;
+
+//        SslContextFactory sslContextFactory = null;
+        SslContextFactory sslContextFactory = new SslContextFactory();
+        sslContextFactory.setEndpointIdentificationAlgorithm("");
+        sslContextFactory.setKeyStorePath("src/test/resources/keystore.jks");
+        sslContextFactory.setKeyStorePassword("storepwd");
+        sslContextFactory.setTrustStorePath("src/test/resources/truststore.jks");
+        sslContextFactory.setTrustStorePassword("storepwd");
+
+        Server server = new Server();
+
+        Map<Short, PushStrategy> pushStrategies = new HashMap<>();
+        pushStrategies.put(SPDY.V3, new ReferrerPushStrategy());
+        HTTPSPDYServerConnector connector = new HTTPSPDYServerConnector(server, sslContextFactory, pushStrategies);
+        connector.setPort(port);
+        server.addConnector(connector);
+
+        String root = "/home/simon/programs/wordpress-3.7.1";
+
+        ServletContextHandler context = new ServletContextHandler(server, "/");
+        context.setResourceBase(root);
+        context.setWelcomeFiles(new String[]{"index.php"});
+
+        // Serve static resources
+        ServletHolder defaultServlet = new ServletHolder(DefaultServlet.class);
+        defaultServlet.setName("default");
+        context.addServlet(defaultServlet, "/");
+
+        FilterHolder tryFileFilter = context.addFilter(TryFilesFilter.class, "/*", EnumSet.of(DispatcherType.REQUEST));
+        tryFileFilter.setInitParameter(TryFilesFilter.ROOT_INIT_PARAM, root);
+//        tryFileFilter.setInitParameter(TryFilesFilter.FILES_INIT_PARAM, "$path $path/index.php?$query"); // Permalink /?p=123
+        tryFileFilter.setInitParameter(TryFilesFilter.FILES_INIT_PARAM, "$path /index.php?p=$path&$query"); // Permalink /%year%/%monthnum%/%postname%
+
+        // FastCGI
+        ServletHolder fcgiServlet = new ServletHolder(FastCGIProxyServlet.class);
+        fcgiServlet.setInitParameter(FastCGIProxyServlet.SCRIPT_ROOT_INIT_PARAM, root);
+        fcgiServlet.setInitParameter("proxyTo", "http://localhost:9000");
+        fcgiServlet.setInitParameter("prefix", "/");
+        fcgiServlet.setInitParameter(FastCGIProxyServlet.SCRIPT_PATTERN_INIT_PARAM, "(.+?\\.php)");
+        context.addServlet(fcgiServlet, "*.php");
+
+        server.start();
+    }
+}