Tomcat example source code file (SSIServletExternalResolver.java)

This example Tomcat source code file (SSIServletExternalResolver.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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The Tomcat SSIServletExternalResolver.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.ssi;


import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLDecoder;
import java.util.Collection;
import java.util.Date;
import java.util.Enumeration;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.connector.Request;
import org.apache.coyote.Constants;

/**
 * An implementation of SSIExternalResolver that is used with servlets.
 * 
 * @author Dan Sandberg
 * @author David Becker
 * @version $Revision: 531303 $, $Date: 2007-04-23 02:24:01 +0200 (lun., 23 avr. 2007) $
 */
public class SSIServletExternalResolver implements SSIExternalResolver {
    protected final String VARIABLE_NAMES[] = {"AUTH_TYPE", "CONTENT_LENGTH",
            "CONTENT_TYPE", "DOCUMENT_NAME", "DOCUMENT_URI",
            "GATEWAY_INTERFACE", "HTTP_ACCEPT", "HTTP_ACCEPT_ENCODING",
            "HTTP_ACCEPT_LANGUAGE", "HTTP_CONNECTION", "HTTP_HOST",
            "HTTP_REFERER", "HTTP_USER_AGENT", "PATH_INFO", "PATH_TRANSLATED",
            "QUERY_STRING", "QUERY_STRING_UNESCAPED", "REMOTE_ADDR",
            "REMOTE_HOST", "REMOTE_PORT", "REMOTE_USER", "REQUEST_METHOD",
            "REQUEST_URI", "SCRIPT_FILENAME", "SCRIPT_NAME", "SERVER_ADDR",
            "SERVER_NAME", "SERVER_PORT", "SERVER_PROTOCOL", "SERVER_SOFTWARE",
            "UNIQUE_ID"};
    protected ServletContext context;
    protected HttpServletRequest req;
    protected HttpServletResponse res;
    protected boolean isVirtualWebappRelative;
    protected int debug;
    protected String inputEncoding;

    public SSIServletExternalResolver(ServletContext context,
            HttpServletRequest req, HttpServletResponse res,
            boolean isVirtualWebappRelative, int debug, String inputEncoding) {
        this.context = context;
        this.req = req;
        this.res = res;
        this.isVirtualWebappRelative = isVirtualWebappRelative;
        this.debug = debug;
        this.inputEncoding = inputEncoding;
    }


    public void log(String message, Throwable throwable) {
        //We can't assume that Servlet.log( message, null )
        //is the same as Servlet.log( message ), since API
        //doesn't seem to say so.
        if (throwable != null) {
            context.log(message, throwable);
        } else {
            context.log(message);
        }
    }


    public void addVariableNames(Collection variableNames) {
        for (int i = 0; i < VARIABLE_NAMES.length; i++) {
            String variableName = VARIABLE_NAMES[i];
            String variableValue = getVariableValue(variableName);
            if (variableValue != null) {
                variableNames.add(variableName);
            }
        }
        Enumeration e = req.getAttributeNames();
        while (e.hasMoreElements()) {
            String name = (String)e.nextElement();
            if (!isNameReserved(name)) {
                variableNames.add(name);
            }
        }
    }


    protected Object getReqAttributeIgnoreCase(String targetName) {
        Object object = null;
        if (!isNameReserved(targetName)) {
            object = req.getAttribute(targetName);
            if (object == null) {
                Enumeration e = req.getAttributeNames();
                while (e.hasMoreElements()) {
                    String name = (String)e.nextElement();
                    if (targetName.equalsIgnoreCase(name)
                            && !isNameReserved(name)) {
                        object = req.getAttribute(name);
                        if (object != null) {
                            break;
                        }
                    }
                }
            }
        }
        return object;
    }


    protected boolean isNameReserved(String name) {
        return name.startsWith("java.") || name.startsWith("javax.")
                || name.startsWith("sun.");
    }


    public void setVariableValue(String name, String value) {
        if (!isNameReserved(name)) {
            req.setAttribute(name, value);
        }
    }


    public String getVariableValue(String name) {
        String retVal = null;
        Object object = getReqAttributeIgnoreCase(name);
        if (object != null) {
            retVal = object.toString();
        } else {
            retVal = getCGIVariable(name);
        }
        return retVal;
    }


    protected String getCGIVariable(String name) {
        String retVal = null;
        String[] nameParts = name.toUpperCase().split("_");
        int requiredParts = 2;
        if (nameParts.length == 1) {
            if (nameParts[0].equals("PATH")) {
                requiredParts = 1;
                retVal = null; // Not implemented
            }
        }
        else if (nameParts[0].equals("AUTH")) {
            if (nameParts[1].equals("TYPE")) {
                retVal = req.getAuthType();
            }
        } else if(nameParts[0].equals("CONTENT")) {
            if (nameParts[1].equals("LENGTH")) {
                int contentLength = req.getContentLength();
                if (contentLength >= 0) {
                    retVal = Integer.toString(contentLength);
                }
            } else if (nameParts[1].equals("TYPE")) {
                retVal = req.getContentType();
            }
        } else if (nameParts[0].equals("DOCUMENT")) {
            if (nameParts[1].equals("NAME")) {
                String requestURI = req.getRequestURI();
                retVal = requestURI.substring(requestURI.lastIndexOf('/') + 1);
            } else if (nameParts[1].equals("URI")) {
                retVal = req.getRequestURI();
            }
        } else if (name.equalsIgnoreCase("GATEWAY_INTERFACE")) {
            retVal = "CGI/1.1";
        } else if (nameParts[0].equals("HTTP")) {
            if (nameParts[1].equals("ACCEPT")) {
                String accept = null;
                if (nameParts.length == 2) {
                    accept = "Accept";
                } else if (nameParts[2].equals("ENCODING")) {
                    requiredParts = 3;
                    accept = "Accept-Encoding";
                } else if (nameParts[2].equals("LANGUAGE")) {
                    requiredParts = 3;
                    accept = "Accept-Language";
                }
                if (accept != null) {
                    Enumeration acceptHeaders = req.getHeaders(accept);
                    if (acceptHeaders != null)
                        if (acceptHeaders.hasMoreElements()) {
                            StringBuffer rv = new StringBuffer(
                                    (String) acceptHeaders.nextElement());
                            while (acceptHeaders.hasMoreElements()) {
                                rv.append(", ");
                                rv.append((String) acceptHeaders.nextElement());
                            }
                        retVal = rv.toString();
                    }
                }
            }
            else if (nameParts[1].equals("CONNECTION")) {
                retVal = req.getHeader("Connection");
            }
            else if (nameParts[1].equals("HOST")) {
                retVal = req.getHeader("Host");
            }
            else if (nameParts[1].equals("REFERER")) {
                retVal = req.getHeader("Referer");
            }
            else if (nameParts[1].equals("USER"))
                if (nameParts.length == 3)
                    if (nameParts[2].equals("AGENT")) {
                        requiredParts = 3;
                        retVal = req.getHeader("User-Agent");
                    }

        } else if (nameParts[0].equals("PATH")) {
            if (nameParts[1].equals("INFO")) {
                retVal = req.getPathInfo();
            } else if (nameParts[1].equals("TRANSLATED")) {
                retVal = req.getPathTranslated();
            }
        } else if (nameParts[0].equals("QUERY")) {
            if (nameParts[1].equals("STRING")) {
                String queryString = req.getQueryString();
                if (nameParts.length == 2) {
                    //apache displays this as an empty string rather than (none)
                    retVal = nullToEmptyString(queryString);
                } else if (nameParts[2].equals("UNESCAPED")) {
                    requiredParts = 3;
                    if (queryString != null) {
                        // Use default as a last resort
                        String queryStringEncoding =
                            Constants.DEFAULT_CHARACTER_ENCODING;
                
                        String uriEncoding = null;
                        boolean useBodyEncodingForURI = false;
                
                        // Get encoding settings from request / connector if
                        // possible
                        String requestEncoding = req.getCharacterEncoding();
                        if (req instanceof Request) {
                            uriEncoding =
                                ((Request)req).getConnector().getURIEncoding();
                            useBodyEncodingForURI = ((Request)req)
                                    .getConnector().getUseBodyEncodingForURI();
                        }
                
                        // If valid, apply settings from request / connector
                        if (uriEncoding != null) {
                            queryStringEncoding = uriEncoding;
                        } else if(useBodyEncodingForURI) {
                            if (requestEncoding != null) {
                                queryStringEncoding = requestEncoding;
                            }
                        }
                
                        try {
                            retVal = URLDecoder.decode(queryString,
                                    queryStringEncoding);                       
                        } catch (UnsupportedEncodingException e) {
                            retVal = queryString;
                        }
                    }
                }
            }
        } else if(nameParts[0].equals("REMOTE")) {
            if (nameParts[1].equals("ADDR")) {
                retVal = req.getRemoteAddr();
            } else if (nameParts[1].equals("HOST")) {
                retVal = req.getRemoteHost();
            } else if (nameParts[1].equals("IDENT")) {
                retVal = null; // Not implemented
            } else if (nameParts[1].equals("PORT")) {
                retVal = Integer.toString( req.getRemotePort());
            } else if (nameParts[1].equals("USER")) {
                retVal = req.getRemoteUser();
            }
        } else if(nameParts[0].equals("REQUEST")) {
            if (nameParts[1].equals("METHOD")) {
                retVal = req.getMethod();
            }
            else if (nameParts[1].equals("URI")) {
                // If this is an error page, get the original URI
                retVal = (String) req.getAttribute(
                        "javax.servlet.forward.request_uri");
                if (retVal == null) retVal=req.getRequestURI();
            }
        } else if (nameParts[0].equals("SCRIPT")) {
            String scriptName = req.getServletPath();
            if (nameParts[1].equals("FILENAME")) {
                retVal = context.getRealPath(scriptName);
            }
            else if (nameParts[1].equals("NAME")) {
                retVal = scriptName;
            }
        } else if (nameParts[0].equals("SERVER")) {
            if (nameParts[1].equals("ADDR")) {
                retVal = req.getLocalAddr();
            }
            if (nameParts[1].equals("NAME")) {
                retVal = req.getServerName();
            } else if (nameParts[1].equals("PORT")) {
                retVal = Integer.toString(req.getServerPort());
            } else if (nameParts[1].equals("PROTOCOL")) {
                retVal = req.getProtocol();
            } else if (nameParts[1].equals("SOFTWARE")) {
                StringBuffer rv = new StringBuffer(context.getServerInfo());
                rv.append(" ");
                rv.append(System.getProperty("java.vm.name"));
                rv.append("/");
                rv.append(System.getProperty("java.vm.version"));
                rv.append(" ");
                rv.append(System.getProperty("os.name"));
                retVal = rv.toString();
            }
        } else if (name.equalsIgnoreCase("UNIQUE_ID")) {
            retVal = req.getRequestedSessionId();
        }
        if (requiredParts != nameParts.length) return null;
            return retVal;
    }

    public Date getCurrentDate() {
        return new Date();
    }


    protected String nullToEmptyString(String string) {
        String retVal = string;
        if (retVal == null) {
            retVal = "";
        }
        return retVal;
    }


    protected String getPathWithoutFileName(String servletPath) {
        String retVal = null;
        int lastSlash = servletPath.lastIndexOf('/');
        if (lastSlash >= 0) {
            //cut off file namee
            retVal = servletPath.substring(0, lastSlash + 1);
        }
        return retVal;
    }


    protected String getPathWithoutContext(String servletPath) {
        String retVal = null;
        int secondSlash = servletPath.indexOf('/', 1);
        if (secondSlash >= 0) {
            //cut off context
            retVal = servletPath.substring(secondSlash);
        }
        return retVal;
    }


    protected String getAbsolutePath(String path) throws IOException {
        String pathWithoutContext = SSIServletRequestUtil.getRelativePath(req);
        String prefix = getPathWithoutFileName(pathWithoutContext);
        if (prefix == null) {
            throw new IOException("Couldn't remove filename from path: "
                    + pathWithoutContext);
        }
        String fullPath = prefix + path;
        String retVal = SSIServletRequestUtil.normalize(fullPath);
        if (retVal == null) {
            throw new IOException("Normalization yielded null on path: "
                    + fullPath);
        }
        return retVal;
    }


    protected ServletContextAndPath getServletContextAndPathFromNonVirtualPath(
            String nonVirtualPath) throws IOException {
        if (nonVirtualPath.startsWith("/") || nonVirtualPath.startsWith("\\")) {
            throw new IOException("A non-virtual path can't be absolute: "
                    + nonVirtualPath);
        }
        if (nonVirtualPath.indexOf("../") >= 0) {
            throw new IOException("A non-virtual path can't contain '../' : "
                    + nonVirtualPath);
        }
        String path = getAbsolutePath(nonVirtualPath);
        ServletContextAndPath csAndP = new ServletContextAndPath(
                context, path);
        return csAndP;
    }


    protected ServletContextAndPath getServletContextAndPathFromVirtualPath(
            String virtualPath) throws IOException {

        if (!virtualPath.startsWith("/") && !virtualPath.startsWith("\\")) {
            return new ServletContextAndPath(context,
                    getAbsolutePath(virtualPath));
        } else {
            String normalized = SSIServletRequestUtil.normalize(virtualPath);
            if (isVirtualWebappRelative) {
                return new ServletContextAndPath(context, normalized);
            } else {
                ServletContext normContext = context.getContext(normalized);
                if (normContext == null) {
                    throw new IOException("Couldn't get context for path: "
                            + normalized);
                }
                //If it's the root context, then there is no context element
                // to remove,
                // ie:
                // '/file1.shtml' vs '/appName1/file1.shtml'
                if (!isRootContext(normContext)) {
                    String noContext = getPathWithoutContext(normalized);
                    if (noContext == null) {
                        throw new IOException(
                                "Couldn't remove context from path: "
                                        + normalized);
                    }
                    return new ServletContextAndPath(normContext, noContext);
                } else {
                    return new ServletContextAndPath(normContext, normalized);
                }
            }
        }
    }


    //Assumes servletContext is not-null
    //Assumes that identity comparison will be true for the same context
    //Assuming the above, getContext("/") will be non-null as long as the root
    // context is
    // accessible.
    //If it isn't, then servletContext can't be the root context anyway, hence
    // they will
    // not match.
    protected boolean isRootContext(ServletContext servletContext) {
        return servletContext == servletContext.getContext("/");
    }


    protected ServletContextAndPath getServletContextAndPath(
            String originalPath, boolean virtual) throws IOException {
        ServletContextAndPath csAndP = null;
        if (debug > 0) {
            log("SSIServletExternalResolver.getServletContextAndPath( "
                    + originalPath + ", " + virtual + ")", null);
        }
        if (virtual) {
            csAndP = getServletContextAndPathFromVirtualPath(originalPath);
        } else {
            csAndP = getServletContextAndPathFromNonVirtualPath(originalPath);
        }
        return csAndP;
    }


    protected URLConnection getURLConnection(String originalPath,
            boolean virtual) throws IOException {
        ServletContextAndPath csAndP = getServletContextAndPath(originalPath,
                virtual);
        ServletContext context = csAndP.getServletContext();
        String path = csAndP.getPath();
        URL url = context.getResource(path);
        if (url == null) {
            throw new IOException("Context did not contain resource: " + path);
        }
        URLConnection urlConnection = url.openConnection();
        return urlConnection;
    }


    public long getFileLastModified(String path, boolean virtual)
            throws IOException {
        long lastModified = 0;
        try {
            URLConnection urlConnection = getURLConnection(path, virtual);
            lastModified = urlConnection.getLastModified();
        } catch (IOException e) {
            // Ignore this. It will always fail for non-file based includes
        }
        return lastModified;
    }


    public long getFileSize(String path, boolean virtual) throws IOException {
        long fileSize = -1;
        try {
            URLConnection urlConnection = getURLConnection(path, virtual);
            fileSize = urlConnection.getContentLength();
        } catch (IOException e) {
            // Ignore this. It will always fail for non-file based includes
        }
        return fileSize;
    }


    //We are making lots of unnecessary copies of the included data here. If
    //someone ever complains that this is slow, we should connect the included
    // stream to the print writer that SSICommand uses.
    public String getFileText(String originalPath, boolean virtual)
            throws IOException {
        try {
            ServletContextAndPath csAndP = getServletContextAndPath(
                    originalPath, virtual);
            ServletContext context = csAndP.getServletContext();
            String path = csAndP.getPath();
            RequestDispatcher rd = context.getRequestDispatcher(path);
            if (rd == null) {
                throw new IOException(
                        "Couldn't get request dispatcher for path: " + path);
            }
            ByteArrayServletOutputStream basos =
                new ByteArrayServletOutputStream();
            ResponseIncludeWrapper responseIncludeWrapper =
                new ResponseIncludeWrapper(context, req, res, basos);
            rd.include(req, responseIncludeWrapper);
            //We can't assume the included servlet flushed its output
            responseIncludeWrapper.flushOutputStreamOrWriter();
            byte[] bytes = basos.toByteArray();

            //Assume platform default encoding unless otherwise specified
            String retVal;
            if (inputEncoding == null) {
                retVal = new String( bytes );
            } else {
                retVal = new String (bytes, inputEncoding);
            }

            //make an assumption that an empty response is a failure. This is
            // a problem
            // if a truly empty file
            //were included, but not sure how else to tell.
            if (retVal.equals("") && !req.getMethod().equalsIgnoreCase(
                    org.apache.coyote.http11.Constants.HEAD)) {
                throw new IOException("Couldn't find file: " + path);
            }
            return retVal;
        } catch (ServletException e) {
            throw new IOException("Couldn't include file: " + originalPath
                    + " because of ServletException: " + e.getMessage());
        }
    }

    protected class ServletContextAndPath {
        protected ServletContext servletContext;
        protected String path;


        public ServletContextAndPath(ServletContext servletContext,
                                     String path) {
            this.servletContext = servletContext;
            this.path = path;
        }


        public ServletContext getServletContext() {
            return servletContext;
        }


        public String getPath() {
            return path;
        }
    }
}