Java tutorial
#set($symbol_pound='#')#set($symbol_dollar='$')#set($symbol_escape='\') /* * Copyright 2011-2014 Hippo B.V. (http://www.onehippo.com) * * Licensed 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. * * modified by Ebrahim Aharpour */ package ${package}.ui; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; import java.util.HashMap; import java.util.HashSet; import java.util.Map; import java.util.Set; import java.util.regex.Pattern; import java.util.zip.GZIPOutputStream; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Serves resources from either web application or classpath. * * <p/> * A typical configuration is to set classpath resource path and map a servlet * path to this servlet. * * <xmp> <servlet> <servlet-name>ExampleResourceServlet</servlet-name> * <servlet-class>org.hippoecm.hst.servlet.ResourceServlet</servlet-class> * <init-param> <param-name>jarPathPrefix</param-name> * <param-value>/META-INF/example/myapp/skin</param-value> </init-param> * </servlet> * * <servlet-mapping> <servlet-name>ExampleResourceServlet</servlet-name> * <url-pattern>/myapp/skin/*</url-pattern> </servlet-mapping> </xmp> * * <p/> * * With the configuration above, requests by paths, "/myapp/skin/*", will be * served by <CODE>ExampleResourceServlet</CODE>, which reads the target * resource from the configured classpath resource path, * "/META-INF/example/myapp/skin". For example, if the request path info is * "/myapp/skin/example.png", then the servlet will find the corresponding * classpath resource, "classpath:META-INF/example/myapp/skin/example.png", to * serve the request. * * <p/> * * <p> * The following init parameters are available: * </p> * <table border="2"> * <tr> * <th>Init parameter name</th> * <th>Description</th> * <th>Example value</th> * <th>Default value</th> * </tr> * <tr> * <td>jarPathPrefix</td> * <td>Classpath resource path prefix</td> * <td>META-INF/example/myapp/skin</td> * <td>META-INF</td> * </tr> * <tr> * <td>cacheTimeout</td> * <td> * Millisecond value to set cache control HTTP headers: 'Expires' and * 'Cache-Control'. These cache control HTTP headers will be written only if * this value is greater than zero. Otherwise, the cache control HTTP headers * are not written.</td> * <td>0</td> * <td>31556926</td> * </tr> * <tr> * <td>gzipEnabled</td> * <td>Flag to enable/disable gzip encoded response for specified mimeTypes, * which can be configured by 'compressedMimeTypes' init parameter.</td> * <td>false</td> * <td>true</td> * </tr> * <tr> * <td>webResourceEnabled</td> * <td> * Flag to enable/disable to read resources from the servlet context on web * application resources. If this is enabled, then the servlet will try to read * a resource from the web application first by the request path info.</td> * <td>false</td> * <td>true</td> * </tr> * <tr> * <td>jarResourceEnabled</td> * <td> * Flag to enable/disable to read resources from the classpath resources. If * this is enabled, then the servlet will try to read a resource from the * classpath.</td> * <td>false</td> * <td>true</td> * </tr> * <tr> * <td>allowedResourcePaths</td> * <td>Sets resource path regex patterns which are allowed to serve by this * servlet.</td> * <td> * * <pre> * ^/.*${symbol_escape}${symbol_escape}.js, * ^/.*${symbol_escape}${symbol_escape}.css, * ^/.*${symbol_escape}${symbol_escape}.png, * ^/.*${symbol_escape}${symbol_escape}.gif, * ^/.*${symbol_escape}${symbol_escape}.ico, * ^/.*${symbol_escape}${symbol_escape}.jpg, * ^/.*${symbol_escape}${symbol_escape}.jpeg, * ^/.*${symbol_escape}${symbol_escape}.swf, * ^/.*${symbol_escape}${symbol_escape}.txt * * <pre></td> * <td> * * <pre> * ^/.*${symbol_escape}${symbol_escape}.js, * ^/.*${symbol_escape}${symbol_escape}.css, * ^/.*${symbol_escape}${symbol_escape}.png, * ^/.*${symbol_escape}${symbol_escape}.gif, * ^/.*${symbol_escape}${symbol_escape}.ico, * ^/.*${symbol_escape}${symbol_escape}.jpg, * ^/.*${symbol_escape}${symbol_escape}.jpeg, * ^/.*${symbol_escape}${symbol_escape}.eot, * ^/.*${symbol_escape}${symbol_escape}.otf, * ^/.*${symbol_escape}${symbol_escape}.svg, * ^/.*${symbol_escape}${symbol_escape}.swf, * ^/.*${symbol_escape}${symbol_escape}.ttf, * ^/.*${symbol_escape}${symbol_escape}.woff * * <pre></td> * </tr> * <tr> * <td>mimeTypes</td> * <td> * Sets mimeType mappings to override (or add) from the default mimeType * mappings of the web application. If a proper mimeType is not found by this * mapping, then it will look up a mimeType from the web application.</td> * <td> * * <pre> * .css = text/css, * .js = text/javascript, * .gif = image/gif, * .png = image/png, * .ico = image/vnd.microsoft.icon, * .jpg = image/jpeg, * .jpeg = image/jpeg, * .swf = application/x-shockwave-flash, * .txt = text/plain * </pre> * * </td> * <td> * * <pre> * .css = text/css, * .js = text/javascript, * .gif = image/gif, * .png = image/png, * .ico = image/vnd.microsoft.icon, * .jpg = image/jpeg, * .jpeg = image/jpeg, * .eot = application/vnd.ms-fontobject, * .otf = application/vnd.ms-opentype, * .svg = image/svg+xml, * .swf = application/x-shockwave-flash * .ttf = application/x-font-ttf, * .woff = application/font-woff, * </pre> * * </td> * </tr> * <tr> * <td>compressedMimeTypes</td> * <td> * Sets mimeTypes which can be compressed to serve the resource by this servlet. * If a resource is in this kind of mimeTypes, then the servlet will write a * compressed response in gzip encoding.</td> * <td> * * <pre> * text/.*, * application/json * </pre> * * </td> * <td> * * <pre> * text/.* * </pre> * * </td> * </tr> * </table> * <p/> */ public class ResourceServlet extends HttpServlet { private static final long serialVersionUID = 1L; private static final Logger LOG = LoggerFactory.getLogger(ResourceServlet.class); private static final Pattern WEBAPP_PROTECTED_PATH = Pattern.compile("/?WEB-INF/.*"); private static final String HTTP_LAST_MODIFIED_HEADER = "Last-Modified"; private static final String HTTP_EXPIRES_HEADER = "Expires"; private static final String HTTP_CACHE_CONTROL_HEADER = "Cache-Control"; private static final Set<Pattern> DEFAULT_ALLOWED_RESOURCE_PATHS = new HashSet<Pattern>(); static { DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.js")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.css")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.html")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.htm")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.png")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.gif")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.ico")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.jpg")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.jpeg")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.json")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.eot")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.map")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.otf")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.svg")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.swf")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.ttf")); DEFAULT_ALLOWED_RESOURCE_PATHS.add(Pattern.compile("^/.*${symbol_escape}${symbol_escape}.woff")); } private static final Map<String, String> DEFAULT_MIME_TYPES = new HashMap<String, String>(); static { DEFAULT_MIME_TYPES.put(".css", "text/css"); DEFAULT_MIME_TYPES.put(".html", "text/html"); DEFAULT_MIME_TYPES.put(".htm", "text/html"); DEFAULT_MIME_TYPES.put(".js", "text/javascript"); DEFAULT_MIME_TYPES.put(".gif", "image/gif"); DEFAULT_MIME_TYPES.put(".png", "image/png"); DEFAULT_MIME_TYPES.put(".ico", "image/vnd.microsoft.icon"); DEFAULT_MIME_TYPES.put(".jpg", "image/jpeg"); DEFAULT_MIME_TYPES.put(".jpeg", "image/jpeg"); DEFAULT_MIME_TYPES.put(".json", "application/json"); DEFAULT_MIME_TYPES.put(".eot", "application/vnd.ms-fontobject"); DEFAULT_MIME_TYPES.put(".map", "application/json"); DEFAULT_MIME_TYPES.put(".otf", "application/vnd.ms-opentype"); DEFAULT_MIME_TYPES.put(".svg", "image/svg+xml"); DEFAULT_MIME_TYPES.put(".swf", "application/x-shockwave-flash"); DEFAULT_MIME_TYPES.put(".ttf", "application/x-font-ttf"); DEFAULT_MIME_TYPES.put(".woff", "application/font-woff"); } private static final Set<Pattern> DEFAULT_COMPRESSED_MIME_TYPES = new HashSet<Pattern>(); static { DEFAULT_COMPRESSED_MIME_TYPES.add(Pattern.compile("text/.*")); } private Set<Pattern> allowedResourcePaths; private Map<String, String> mimeTypes; private Set<Pattern> compressedMimeTypes; private String jarPathPrefix; private int cacheTimeout; private boolean gzipEnabled; private boolean webResourceEnabled; private boolean jarResourceEnabled; @Override public void init() throws ServletException { jarPathPrefix = getInitParameter("jarPathPrefix", "META-INF"); cacheTimeout = Integer.parseInt(getInitParameter("cacheTimeout", "31556926")); gzipEnabled = Boolean.parseBoolean(getInitParameter("gzipEnabled", "true")); webResourceEnabled = Boolean.parseBoolean(getInitParameter("webResourceEnabled", "true")); jarResourceEnabled = Boolean.parseBoolean(getInitParameter("jarResourceEnabled", "true")); allowedResourcePaths = new HashSet<Pattern>(DEFAULT_ALLOWED_RESOURCE_PATHS); mimeTypes = new HashMap<String, String>(DEFAULT_MIME_TYPES); compressedMimeTypes = new HashSet<Pattern>(DEFAULT_COMPRESSED_MIME_TYPES); String param = getInitParameter("allowedResourcePaths", null); if (!StringUtils.isBlank(param)) { allowedResourcePaths = new HashSet<Pattern>(); String[] patterns = StringUtils.split(param, ", ${symbol_escape}t${symbol_escape}r${symbol_escape}n"); for (int i = 0; i < patterns.length; i++) { if (!StringUtils.isBlank(patterns[i])) { allowedResourcePaths.add(Pattern.compile(patterns[i])); } } } param = getInitParameter("mimeTypes", null); if (!StringUtils.isBlank(param)) { mimeTypes = new HashMap<String, String>(); String[] pairs = StringUtils.split(param, ",${symbol_escape}t${symbol_escape}r${symbol_escape}n"); for (int i = 0; i < pairs.length; i++) { if (!StringUtils.isBlank(pairs[i])) { String[] pair = StringUtils.split(pairs[i], "="); if (pair.length > 1) { mimeTypes.put(StringUtils.trim(pair[0]), StringUtils.trim(pair[1])); } } } } param = getInitParameter("compressedMimeTypes", null); if (!StringUtils.isBlank(param)) { compressedMimeTypes = new HashSet<Pattern>(); String[] patterns = StringUtils.split(param, ", ${symbol_escape}t${symbol_escape}r${symbol_escape}n"); for (int i = 0; i < patterns.length; i++) { if (!StringUtils.isBlank(patterns[i])) { compressedMimeTypes.add(Pattern.compile(patterns[i])); } } } } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String resourcePath = StringUtils.substringBefore(request.getPathInfo(), ";"); if (LOG.isDebugEnabled()) { LOG.debug("Processing request for resource {}.", resourcePath); } URL resource = getResourceURL(resourcePath); if (resource == null) { if (LOG.isDebugEnabled()) { LOG.debug("Resource not found: {}", resourcePath); } response.sendError(HttpServletResponse.SC_NOT_FOUND); return; } long ifModifiedSince = request.getDateHeader("If-Modified-Since"); URLConnection conn = resource.openConnection(); long lastModified = conn.getLastModified(); if (ifModifiedSince >= lastModified) { if (LOG.isDebugEnabled()) { LOG.debug("Resource: {} Not Modified.", resourcePath); } response.setStatus(304); return; } int contentLength = conn.getContentLength(); prepareResponse(response, resource, lastModified, contentLength); OutputStream out = selectOutputStream(request, response); try { InputStream is = conn.getInputStream(); try { byte[] buffer = new byte[1024]; int bytesRead = -1; while ((bytesRead = is.read(buffer)) != -1) { out.write(buffer, 0, bytesRead); } } finally { is.close(); } } finally { out.close(); } } private URL getResourceURL(String resourcePath) throws MalformedURLException { if (!isAllowed(resourcePath)) { if (LOG.isWarnEnabled()) { LOG.warn("An attempt to access a protected resource at {} was disallowed.", resourcePath); } return null; } URL resource = null; if (webResourceEnabled) { resource = getServletContext().getResource(resourcePath); } if (resource == null && jarResourceEnabled) { resource = getJarResource(resourcePath); } return resource; } private boolean isAllowed(String resourcePath) { if (webResourceEnabled && WEBAPP_PROTECTED_PATH.matcher(resourcePath).matches()) { return false; } for (Pattern p : allowedResourcePaths) { if (p.matcher(resourcePath).matches()) { return true; } } return false; } private URL getJarResource(String resourcePath) { String jarResourcePath = jarPathPrefix + resourcePath; if (jarResourcePath.startsWith("/")) { jarResourcePath = jarResourcePath.substring(1); } if (LOG.isDebugEnabled()) { LOG.debug("Searching classpath for resource: {}", jarResourcePath); } return getDefaultClassLoader().getResource(jarResourcePath); } private void prepareResponse(HttpServletResponse response, URL resource, long lastModified, int contentLength) throws IOException { String resourcePath = resource.getPath(); String mimeType = null; int offset = resourcePath.lastIndexOf('.'); if (-1 != offset) { String extension = resource.getPath().substring(offset); mimeType = mimeTypes.get(extension); } if (mimeType == null) { mimeType = getServletContext().getMimeType(resourcePath); if (LOG.isDebugEnabled()) { LOG.debug("Fallback to the mimeType '{}' from servlet context for {}.", mimeType, resourcePath); } } if (mimeType == null) { if (LOG.isWarnEnabled()) { LOG.warn("No mime-type mapping for resource path: {}. Fallback to 'application/octet-stream'.", resourcePath); } mimeType = "application/octet-stream"; } response.setDateHeader(HTTP_LAST_MODIFIED_HEADER, lastModified); response.setContentLength(contentLength); response.setContentType(mimeType); if (cacheTimeout > 0) { // Http 1.0 header response.setDateHeader(HTTP_EXPIRES_HEADER, System.currentTimeMillis() + cacheTimeout * 1000L); // Http 1.1 header response.setHeader(HTTP_CACHE_CONTROL_HEADER, "max-age=" + cacheTimeout); } else { // Http 1.0 header response.setDateHeader(HTTP_EXPIRES_HEADER, -1); // Http 1.1 header response.setHeader(HTTP_CACHE_CONTROL_HEADER, "no-cache"); } } private OutputStream selectOutputStream(HttpServletRequest request, HttpServletResponse response) throws IOException { if (gzipEnabled) { String mimeType = response.getContentType(); if (matchesCompressedMimeTypes(mimeType)) { String acceptEncoding = request.getHeader("Accept-Encoding"); if (acceptEncoding != null && acceptEncoding.indexOf("gzip") != -1) { if (LOG.isDebugEnabled()) { LOG.debug("Enabling GZIP compression for the current response."); } return new GZIPResponseStream(response); } } } return response.getOutputStream(); } private boolean matchesCompressedMimeTypes(String mimeType) { for (Pattern pattern : compressedMimeTypes) { if (pattern.matcher(mimeType).matches()) { return true; } } return false; } private String getInitParameter(String name, String defaultValue) { String value = getServletConfig().getInitParameter(name); if (value == null) { value = defaultValue; } return value; } private ClassLoader getDefaultClassLoader() { ClassLoader cl = null; try { cl = Thread.currentThread().getContextClassLoader(); } catch (Exception ex) { LOG.debug("Cannot access thread context ClassLoader - falling back to system", ex); // Cannot access thread context ClassLoader - falling back to system // class loader... } if (cl == null) { // No thread context class loader -> use class loader of this class. cl = getClass().getClassLoader(); } return cl; } private class GZIPResponseStream extends ServletOutputStream { private ByteArrayOutputStream byteStream = null; private GZIPOutputStream gzipStream = null; private boolean closed = false; private HttpServletResponse response = null; private ServletOutputStream servletStream = null; public GZIPResponseStream(HttpServletResponse response) throws IOException { super(); closed = false; this.response = response; this.servletStream = response.getOutputStream(); byteStream = new ByteArrayOutputStream(); gzipStream = new GZIPOutputStream(byteStream); } public void close() throws IOException { if (closed) { throw new IOException("This output stream has already been closed"); } gzipStream.finish(); byte[] bytes = byteStream.toByteArray(); response.setContentLength(bytes.length); response.addHeader("Content-Encoding", "gzip"); servletStream.write(bytes); servletStream.flush(); servletStream.close(); closed = true; } public void flush() throws IOException { if (closed) { throw new IOException("Cannot flush a closed output stream"); } gzipStream.flush(); } public void write(int b) throws IOException { if (closed) { throw new IOException("Cannot write to a closed output stream"); } gzipStream.write((byte) b); } public void write(byte b[]) throws IOException { write(b, 0, b.length); } public void write(byte b[], int off, int len) throws IOException { if (closed) { throw new IOException("Cannot write to a closed output stream"); } gzipStream.write(b, off, len); } } }