org.opencms.main.CmsStaticResourceHandler Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.main;
import org.opencms.util.CmsStringUtil;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
/**
* Handles the requests for static resources located in the classpath.
*/
public class CmsStaticResourceHandler implements I_CmsRequestHandler {
/** The handler name. */
public static final String HANDLER_NAME = "Static";
/** The static resource prefix '/handleStatic'. */
public static final String STATIC_RESOURCE_PREFIX = OpenCmsServlet.HANDLE_PATH + HANDLER_NAME;
/** The default output buffer size. */
private static final int DEFAULT_BUFFER_SIZE = 32 * 1024;
/** Default cache lifetime in seconds. */
private static final int DEFAULT_CACHE_TIME = 3600;
/** The handler names. */
private static final String[] HANDLER_NAMES = new String[] {HANDLER_NAME};
/** The log object for this class. */
private static final Log LOG = CmsLog.getLog(CmsStaticResourceHandler.class);
/** The regular expression to remove the static resource path prefix. */
private static String m_removePrefixRegex;
/** The regular expression to identify static resource paths. */
private static String m_staticResourceRegex;
/** The opencms path prefix for static resources. */
private static final String OPENCMS_PATH_PREFIX = "OPENCMS/";
/**
* Returns the context for static resources served from the class path, e.g. "/opencms/handleStatic/v5976v".
*
* @param opencmsContext the OpenCms context
* @param opencmsVersion the OpenCms version
*
* @return the static resource context
*/
public static String getStaticResourceContext(String opencmsContext, String opencmsVersion) {
return opencmsContext + STATIC_RESOURCE_PREFIX + "/v" + opencmsVersion.hashCode() + "v";
}
/**
* Returns the URL to a static resource.
*
* @param resourcePath the static resource path
*
* @return the resource URL
*/
public static URL getStaticResourceURL(String resourcePath) {
URL resourceURL = null;
if (isStaticResourceUri(resourcePath)) {
String path = removeStaticResourcePrefix(resourcePath);
path = CmsStringUtil.joinPaths(OPENCMS_PATH_PREFIX, path);
resourceURL = OpenCms.getSystemInfo().getClass().getClassLoader().getResource(path);
}
return resourceURL;
}
/**
* Returns if the given URI points to a static resource.
*
* @param path the path to test
*
* @return true in case the given URI points to a static resource
*/
public static boolean isStaticResourceUri(String path) {
return (path != null) && path.matches(getStaticResourceRegex());
}
/**
* Returns if the given URI points to a static resource.
*
* @param uri the URI to test
*
* @return true in case the given URI points to a static resource
*/
public static boolean isStaticResourceUri(URI uri) {
return (uri != null) && isStaticResourceUri(uri.getPath());
}
/**
* Removes the static resource path prefix.
*
* @param path the path
*
* @return the modified path
*/
public static String removeStaticResourcePrefix(String path) {
return path.replaceFirst(getRemovePrefixRegex(), "");
}
/**
* Returns the regular expression to remove the static resource path prefix.
*
* @return the regular expression to remove the static resource path prefix
*/
private static String getRemovePrefixRegex() {
if (m_removePrefixRegex == null) {
m_removePrefixRegex = "^("
+ OpenCms.getStaticExportManager().getVfsPrefix()
+ ")?"
+ STATIC_RESOURCE_PREFIX
+ "(/v-?\\d+v/)?";
}
return m_removePrefixRegex;
}
/**
* Returns the regular expression to identify static resource paths.
*
* @return the regular expression to identify static resource paths
*/
private static String getStaticResourceRegex() {
if (m_staticResourceRegex == null) {
m_staticResourceRegex = getRemovePrefixRegex() + ".*";
}
return m_staticResourceRegex;
}
/**
* @see org.opencms.main.I_CmsRequestHandler#getHandlerNames()
*/
public String[] getHandlerNames() {
return HANDLER_NAMES;
}
/**
* @see org.opencms.main.I_CmsRequestHandler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse, java.lang.String)
*/
public void handle(HttpServletRequest request, HttpServletResponse response, String name) throws IOException {
String path = OpenCmsCore.getInstance().getPathInfo(request);
URL resourceURL = getStaticResourceURL(path);
if (resourceURL != null) {
setResponseHeaders(request, response, path, resourceURL);
writeStaticResourceResponse(request, response, resourceURL);
} else {
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
}
}
/**
* Returns whether this servlet should attempt to serve a precompressed
* version of the given static resource. If this method returns true, the
* suffix {@code .gz} is appended to the URL and the corresponding resource
* is served if it exists. It is assumed that the compression method used is
* gzip. If this method returns false or a compressed version is not found,
* the original URL is used.
*
* The base implementation of this method returns true if and only if the
* request indicates that the client accepts gzip compressed responses and
* the filename extension of the requested resource is .js, .css, or .html.
*
* @param request the request for the resource
* @param url the URL of the requested resource
*
* @return true if the servlet should attempt to serve a precompressed version of the resource, false otherwise
*/
protected boolean allowServePrecompressedResource(HttpServletRequest request, String url) {
String accept = request.getHeader("Accept-Encoding");
return (accept != null)
&& accept.contains("gzip")
&& (url.endsWith(".js") || url.endsWith(".css") || url.endsWith(".html"));
}
/**
* Calculates the cache lifetime for the given filename in seconds. By
* default filenames containing ".nocache." return 0, filenames containing
* ".cache." return one year, all other return the value defined in the
* web.xml using resourceCacheTime (defaults to 1 hour).
*
* @param filename the file name
*
* @return cache lifetime for the given filename in seconds
*/
protected int getCacheTime(String filename) {
/*
* GWT conventions:
*
* - files containing .nocache. will not be cached.
*
* - files containing .cache. will be cached for one year.
*
* https://developers.google.com/web-toolkit/doc/latest/
* DevGuideCompilingAndDebugging#perfect_caching
*/
if (filename.contains(".nocache.")) {
return 0;
}
if (filename.contains(".cache.")) {
return 60 * 60 * 24 * 365;
}
/*
* For all other files, the browser is allowed to cache for 1 hour
* without checking if the file has changed. This forces browsers to
* fetch a new version when the Vaadin version is updated. This will
* cause more requests to the servlet than without this but for high
* volume sites the static files should never be served through the
* servlet.
*/
return DEFAULT_CACHE_TIME;
}
/**
* Sets the response headers.
*
* @param request the request
* @param response the response
* @param filename the file name
* @param resourceURL the resource URL
*/
protected void setResponseHeaders(
HttpServletRequest request,
HttpServletResponse response,
String filename,
URL resourceURL) {
String cacheControl = "public, max-age=0, must-revalidate";
int resourceCacheTime = getCacheTime(filename);
if (resourceCacheTime > 0) {
cacheControl = "max-age=" + String.valueOf(resourceCacheTime);
}
response.setHeader("Cache-Control", cacheControl);
response.setDateHeader("Expires", System.currentTimeMillis() + (resourceCacheTime * 1000));
// Find the modification timestamp
long lastModifiedTime = 0;
URLConnection connection = null;
try {
connection = resourceURL.openConnection();
lastModifiedTime = connection.getLastModified();
// Remove milliseconds to avoid comparison problems (milliseconds
// are not returned by the browser in the "If-Modified-Since"
// header).
lastModifiedTime = lastModifiedTime - (lastModifiedTime % 1000);
response.setDateHeader("Last-Modified", lastModifiedTime);
if (browserHasNewestVersion(request, lastModifiedTime)) {
response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
return;
}
} catch (Exception e) {
// Failed to find out last modified timestamp. Continue without it.
LOG.debug("Failed to find out last modified timestamp. Continuing without it.", e);
} finally {
try {
if (connection != null) {
// Explicitly close the input stream to prevent it
// from remaining hanging
// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4257700
InputStream is = connection.getInputStream();
if (is != null) {
is.close();
}
}
} catch (Exception e) {
LOG.info("Error closing URLConnection input stream", e);
}
}
// Set type mime type if we can determine it based on the filename
String mimetype = OpenCms.getResourceManager().getMimeType(filename, "UTF-8");
if (mimetype != null) {
response.setContentType(mimetype);
}
}
/**
* Writes the contents of the given resourceUrl in the response. Can be
* overridden to add/modify response headers and similar.
*
* @param request the request for the resource
* @param response the response
* @param resourceUrl the url to send
*
* @throws IOException in case writing the response fails
*/
protected void writeStaticResourceResponse(
HttpServletRequest request,
HttpServletResponse response,
URL resourceUrl)
throws IOException {
URLConnection connection = null;
InputStream is = null;
String urlStr = resourceUrl.toExternalForm();
try {
if (allowServePrecompressedResource(request, urlStr)) {
// try to serve a precompressed version if available
try {
connection = new URL(urlStr + ".gz").openConnection();
is = connection.getInputStream();
// set gzip headers
response.setHeader("Content-Encoding", "gzip");
} catch (Exception e) {
LOG.debug("Unexpected exception looking for gzipped version of resource " + urlStr, e);
}
}
if (is == null) {
// precompressed resource not available, get non compressed
connection = resourceUrl.openConnection();
try {
is = connection.getInputStream();
} catch (FileNotFoundException e) {
LOG.debug(e.getMessage(), e);
response.setStatus(HttpServletResponse.SC_NOT_FOUND);
return;
}
}
try {
@SuppressWarnings("null")
int length = connection.getContentLength();
if (length >= 0) {
response.setContentLength(length);
}
} catch (Throwable e) {
LOG.debug(e.getMessage(), e);
// This can be ignored, content length header is not required.
// Need to close the input stream because of
// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4257700 to
// prevent it from hanging, but that is done below.
}
streamContent(response, is);
} finally {
if (is != null) {
is.close();
}
}
}
/**
* Checks if the browser has an up to date cached version of requested
* resource. Currently the check is performed using the "If-Modified-Since"
* header. Could be expanded if needed.
*
* @param request the HttpServletRequest from the browser
* @param resourceLastModifiedTimestamp the timestamp when the resource was last modified. 0 if the last modification time is unknown
*
* @return true if the If-Modified-Since header tells the cached version in the browser is up to date, false otherwise
*/
private boolean browserHasNewestVersion(HttpServletRequest request, long resourceLastModifiedTimestamp) {
if (resourceLastModifiedTimestamp < 1) {
// We do not know when it was modified so the browser cannot have an
// up-to-date version
return false;
}
/*
* The browser can request the resource conditionally using an
* If-Modified-Since header. Check this against the last modification
* time.
*/
try {
// If-Modified-Since represents the timestamp of the version cached
// in the browser
long headerIfModifiedSince = request.getDateHeader("If-Modified-Since");
if (headerIfModifiedSince >= resourceLastModifiedTimestamp) {
// Browser has this an up-to-date version of the resource
return true;
}
} catch (Exception e) {
// Failed to parse header. Fail silently - the browser does not have
// an up-to-date version in its cache.
}
return false;
}
/**
* Streams the input stream to the response.
*
* @param response the response
* @param is the input stream
*
* @throws IOException in case writing to the response fails
*/
private void streamContent(HttpServletResponse response, InputStream is) throws IOException {
OutputStream os = response.getOutputStream();
try {
byte buffer[] = new byte[DEFAULT_BUFFER_SIZE];
int bytes;
while ((bytes = is.read(buffer)) >= 0) {
os.write(buffer, 0, bytes);
}
} finally {
os.close();
}
}
}