org.apache.catalina.filters.ExpiresFilter Maven / Gradle / Ivy
/*
* 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.filters;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
import java.util.regex.Pattern;
import jakarta.servlet.FilterChain;
import jakarta.servlet.FilterConfig;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.WriteListener;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpServletResponseWrapper;
import jakarta.servlet.http.MappingMatch;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
/**
*
* ExpiresFilter is a Java Servlet API port of Apache
* mod_expires to add '{@code Expires}' and
* '{@code Cache-Control: max-age=}' headers to HTTP response according to its
* '{@code Content-Type}'.
*
*
*
* Following documentation is inspired by mod_expires
*
* Summary
*
* This filter controls the setting of the {@code Expires} HTTP header and the
* {@code max-age} directive of the {@code Cache-Control} HTTP header in
* server responses. The expiration date can set to be relative to either the
* time the source file was last modified, or to the time of the client access.
*
*
* These HTTP headers are an instruction to the client about the document's
* validity and persistence. If cached, the document may be fetched from the
* cache rather than from the source until this time has passed. After that, the
* cache copy is considered "expired" and invalid, and a new copy must
* be obtained from the source.
*
*
* To modify {@code Cache-Control} directives other than {@code max-age} (see
* RFC
* 2616 section 14.9), you can use other servlet filters or Apache Httpd
* mod_headers module.
*
* Filter Configuration
Basic configuration to add
* '{@code Expires}' and '{@code Cache-Control: max-age=}'
* headers to images, CSS and JavaScript
*
*
* {@code
*
* ...
*
* ExpiresFilter
* org.apache.catalina.filters.ExpiresFilter
*
* ExpiresByType image
* access plus 10 minutes
*
*
* ExpiresByType text/css
* access plus 10 minutes
*
*
* ExpiresByType application/javascript
* access plus 10 minutes
*
*
* ...
*
* ExpiresFilter
* /*
* REQUEST
*
* ...
*
* }
*
*
* Configuration Parameters
*
* {@code ExpiresByType }
*
* This directive defines the value of the {@code Expires} header and the
* {@code max-age} directive of the {@code Cache-Control} header generated for
* documents of the specified type (e.g., {@code text/html}). The second
* argument sets the number of seconds that will be added to a base time to
* construct the expiration date. The {@code Cache-Control: max-age} is
* calculated by subtracting the request time from the expiration date and
* expressing the result in seconds.
*
*
* The base time is either the last modification time of the file, or the time
* of the client's access to the document. Which should be used is
* specified by the {@code } field; {@code M} means that the
* file's last modification time should be used as the base time, and
* {@code A} means the client's access time should be used. The duration
* is expressed in seconds. {@code A2592000} stands for
* {@code access plus 30 days} in alternate syntax.
*
*
* The difference in effect is subtle. If {@code M} ({@code modification} in
* alternate syntax) is used, all current copies of the document in all caches
* will expire at the same time, which can be good for something like a weekly
* notice that's always found at the same URL. If {@code A} (
* {@code access} or {@code now} in alternate syntax) is used, the date of
* expiration is different for each client; this can be good for image files
* that don't change very often, particularly for a set of related
* documents that all refer to the same images (i.e., the images will be
* accessed repeatedly within a relatively short timespan).
*
*
* Example:
*
*
*
* {@code
*
* ExpiresByType text/html
* access plus 1 month 15 days 2 hours
*
*
*
*
* ExpiresByType image/gif
* A2592000
*
* }
*
*
* Note that this directive only has effect if {@code ExpiresActive On} has
* been specified. It overrides, for the specified MIME type only, any
* expiration date set by the {@code ExpiresDefault} directive.
*
*
* You can also specify the expiration time calculation using an alternate
* syntax, described earlier in this document.
*
*
* {@code ExpiresExcludedResponseStatusCodes}
*
* This directive defines the http response status codes for which the
* {@code ExpiresFilter} will not generate expiration headers. By default, the
* {@code 304} status code ("{@code Not modified}") is skipped. The
* value is a comma separated list of http status codes.
*
*
* This directive is useful to ease usage of {@code ExpiresDefault} directive.
* Indeed, the behavior of {@code 304 Not modified} (which does specify a
* {@code Content-Type} header) combined with {@code Expires} and
* {@code Cache-Control:max-age=} headers can be unnecessarily tricky to
* understand.
*
*
* Configuration sample :
*
*
*
* {@code
*
* ExpiresExcludedResponseStatusCodes
* 302, 500, 503
*
* }
*
*
* ExpiresDefault
*
* This directive sets the default algorithm for calculating the expiration time
* for all documents in the affected realm. It can be overridden on a
* type-by-type basis by the {@code ExpiresByType} directive. See the
* description of that directive for details about the syntax of the argument,
* and the "alternate syntax" description as well.
*
* Alternate Syntax
*
* The {@code ExpiresDefault} and {@code ExpiresByType} directives can also be
* defined in a more readable syntax of the form:
*
*
*
* {@code
*
* ExpiresDefault
* )*
*
*
* ExpiresByType type/encoding
* )*
* }
*
*
* where {@code
*
* - {@code access}
* - {@code now} (equivalent to '{@code access}')
* - {@code modification}
*
*
* The {@code plus} keyword is optional. {@code } should be an
* integer value (acceptable to {@code Integer.parseInt()}), and
* {@code } is one of:
*
*
* - {@code years}
* - {@code months}
* - {@code weeks}
* - {@code days}
* - {@code hours}
* - {@code minutes}
* - {@code seconds}
*
*
* For example, any of the following directives can be used to make documents
* expire 1 month after being accessed, by default:
*
*
*
* {@code
*
* ExpiresDefault
* access plus 1 month
*
*
*
* ExpiresDefault
* access plus 4 weeks
*
*
*
* ExpiresDefault
* access plus 30 days
*
* }
*
*
* The expiry time can be fine-tuned by adding several '
* {@code }' clauses:
*
*
*
* {@code
*
* ExpiresByType text/html
* access plus 1 month 15 days 2 hours
*
*
*
* ExpiresByType image/gif
* modification plus 5 hours 3 minutes
*
* }
*
*
* Note that if you use a modification date based setting, the {@code Expires}
* header will not be added to content that does not come from
* a file on disk. This is due to the fact that there is no modification time
* for such content.
*
* Expiration headers generation eligibility
*
* A response is eligible to be enriched by {@code ExpiresFilter} if :
*
*
* - no expiration header is defined ({@code Expires} header or the
* {@code max-age} directive of the {@code Cache-Control} header),
* - the response status code is not excluded by the directive
* {@code ExpiresExcludedResponseStatusCodes},
* - the {@code Content-Type} of the response matches one of the types
* defined the in {@code ExpiresByType} directives or the
* {@code ExpiresDefault} directive is defined.
*
*
* Note :
*
*
* - If {@code Cache-Control} header contains other directives than
* {@code max-age}, they are concatenated with the {@code max-age} directive
* that is added by the {@code ExpiresFilter}.
*
* Expiration configuration selection
*
* The expiration configuration if elected according to the following algorithm:
*
*
* - {@code ExpiresByType} matching the exact content-type returned by
* {@code HttpServletResponse.getContentType()} possibly including the charset
* (e.g. '{@code text/xml;charset=UTF-8}'),
* - {@code ExpiresByType} matching the content-type without the charset if
* {@code HttpServletResponse.getContentType()} contains a charset (e.g. '
* {@code text/xml;charset=UTF-8}' -> '{@code text/xml}'),
* - {@code ExpiresByType} matching the major type (e.g. substring before
* '{@code /}') of {@code HttpServletResponse.getContentType()}
* (e.g. '{@code text/xml;charset=UTF-8}' -> '{@code text}
* '),
* - {@code ExpiresDefault}
*
* Implementation Details
When to write the expiration headers ?
*
* The {@code ExpiresFilter} traps the 'on before write response
* body' event to decide whether it should generate expiration headers or
* not.
*
*
* To trap the 'before write response body' event, the
* {@code ExpiresFilter} wraps the http servlet response's writer and
* outputStream to intercept calls to the methods {@code write()},
* {@code print()}, {@code close()} and {@code flush()}. For empty response
* body (e.g. empty files), the {@code write()}, {@code print()},
* {@code close()} and {@code flush()} methods are not called; to handle this
* case, the {@code ExpiresFilter}, at the end of its {@code doFilter()}
* method, manually triggers the {@code onBeforeWriteResponseBody()} method.
*
* Configuration syntax
*
* The {@code ExpiresFilter} supports the same configuration syntax as Apache
* Httpd mod_expires.
*
*
* A challenge has been to choose the name of the {@code }
* associated with {@code ExpiresByType} in the {@code }
* declaration. Indeed, Several {@code ExpiresByType} directives can be
* declared when {@code web.xml} syntax does not allow to declare several
* {@code } with the same name.
*
*
* The workaround has been to declare the content type in the
* {@code } rather than in the {@code }.
*
* Designed for extension : the open/close principle
*
* The {@code ExpiresFilter} has been designed for extension following the
* open/close principle.
*
*
* Key methods to override for extension are :
*
*
* -
* {@link #isEligibleToExpirationHeaderGeneration(HttpServletRequest, XHttpServletResponse)}
*
* -
* {@link #getExpirationDate(HttpServletRequest, XHttpServletResponse)}
*
* Troubleshooting
*
* To troubleshoot, enable logging on the
* {@code org.apache.catalina.filters.ExpiresFilter}.
*
*
* Extract of logging.properties
*
*
*
* org.apache.catalina.filters.ExpiresFilter.level = FINE
*
*
* Sample of initialization log message :
*
*
*
* Mar 26, 2010 2:01:41 PM org.apache.catalina.filters.ExpiresFilter init
* FINE: Filter initialized with configuration ExpiresFilter[
* excludedResponseStatusCode=[304],
* default=null,
* byType={
* image=ExpiresConfiguration[startingPoint=ACCESS_TIME, duration=[10 MINUTE]],
* text/css=ExpiresConfiguration[startingPoint=ACCESS_TIME, duration=[10 MINUTE]],
* application/javascript=ExpiresConfiguration[startingPoint=ACCESS_TIME, duration=[10 MINUTE]]}]
*
*
* Sample of per-request log message where {@code ExpiresFilter} adds an
* expiration date
*
*
*
* Mar 26, 2010 2:09:47 PM org.apache.catalina.filters.ExpiresFilter onBeforeWriteResponseBody
* FINE: Request "/tomcat.gif" with response status "200" content-type "image/gif", set expiration date 3/26/10 2:19 PM
*
*
* Sample of per-request log message where {@code ExpiresFilter} does not add
* an expiration date
*
*
*
* Mar 26, 2010 2:10:27 PM org.apache.catalina.filters.ExpiresFilter onBeforeWriteResponseBody
* FINE: Request "/docs/config/manager.html" with response status "200" content-type "text/html", no expiration configured
*
*/
public class ExpiresFilter extends FilterBase {
/**
* Duration composed of an {@link #amount} and a {@link #unit}
*/
protected static class Duration {
protected final int amount;
protected final DurationUnit unit;
public Duration(int amount, DurationUnit unit) {
super();
this.amount = amount;
this.unit = unit;
}
public int getAmount() {
return amount;
}
public DurationUnit getUnit() {
return unit;
}
@Override
public String toString() {
return amount + " " + unit;
}
}
/**
* Duration unit
*/
protected enum DurationUnit {
DAY(Calendar.DAY_OF_YEAR), HOUR(Calendar.HOUR), MINUTE(Calendar.MINUTE), MONTH(
Calendar.MONTH), SECOND(Calendar.SECOND), WEEK(
Calendar.WEEK_OF_YEAR), YEAR(Calendar.YEAR);
private final int calendarField;
private DurationUnit(int calendarField) {
this.calendarField = calendarField;
}
public int getCalendardField() {
return calendarField;
}
}
/**
*
* Main piece of configuration of the filter.
*
*
* Can be expressed like '{@code access plus 1 month 15 days 2 hours}'.
*
*/
protected static class ExpiresConfiguration {
/**
* List of duration elements.
*/
private final List durations;
/**
* Starting point of the elapse to set in the response.
*/
private final StartingPoint startingPoint;
public ExpiresConfiguration(StartingPoint startingPoint,
List durations) {
super();
this.startingPoint = startingPoint;
this.durations = durations;
}
public List getDurations() {
return durations;
}
public StartingPoint getStartingPoint() {
return startingPoint;
}
@Override
public String toString() {
return "ExpiresConfiguration[startingPoint=" + startingPoint +
", duration=" + durations + "]";
}
}
/**
* Expiration configuration starting point. Either the time the
* HTML-page/servlet-response was served ({@link StartingPoint#ACCESS_TIME})
* or the last time the HTML-page/servlet-response was modified (
* {@link StartingPoint#LAST_MODIFICATION_TIME}).
*/
protected enum StartingPoint {
ACCESS_TIME, LAST_MODIFICATION_TIME
}
/**
*
* Wrapping extension of the {@link HttpServletResponse} to yrap the
* "Start Write Response Body" event.
*
*
* For performance optimization : this extended response holds the
* {@link #lastModifiedHeader} and {@link #cacheControlHeader} values access
* to the slow {@link #getHeader(String)} and to spare the {@code string}
* to {@code date} to {@code long} conversion.
*
*/
public class XHttpServletResponse extends HttpServletResponseWrapper {
/**
* Value of the {@code Cache-Control} http response header if it has
* been set.
*/
private String cacheControlHeader;
/**
* Value of the {@code Last-Modified} http response header if it has
* been set.
*/
private long lastModifiedHeader;
private boolean lastModifiedHeaderSet;
private PrintWriter printWriter;
private final HttpServletRequest request;
private ServletOutputStream servletOutputStream;
/**
* Indicates whether calls to write methods ({@code write(...)},
* {@code print(...)}, etc) of the response body have been called or
* not.
*/
private boolean writeResponseBodyStarted;
public XHttpServletResponse(HttpServletRequest request,
HttpServletResponse response) {
super(response);
this.request = request;
}
@Override
public void addDateHeader(String name, long date) {
super.addDateHeader(name, date);
if (!lastModifiedHeaderSet) {
this.lastModifiedHeader = date;
this.lastModifiedHeaderSet = true;
}
}
@Override
public void addHeader(String name, String value) {
super.addHeader(name, value);
if (HEADER_CACHE_CONTROL.equalsIgnoreCase(name) &&
cacheControlHeader == null) {
cacheControlHeader = value;
}
}
public String getCacheControlHeader() {
return cacheControlHeader;
}
public long getLastModifiedHeader() {
return lastModifiedHeader;
}
@Override
public ServletOutputStream getOutputStream() throws IOException {
if (servletOutputStream == null) {
servletOutputStream = new XServletOutputStream(
super.getOutputStream(), request, this);
}
return servletOutputStream;
}
@Override
public PrintWriter getWriter() throws IOException {
if (printWriter == null) {
printWriter = new XPrintWriter(super.getWriter(), request, this);
}
return printWriter;
}
public boolean isLastModifiedHeaderSet() {
return lastModifiedHeaderSet;
}
public boolean isWriteResponseBodyStarted() {
return writeResponseBodyStarted;
}
@Override
public void reset() {
super.reset();
this.lastModifiedHeader = 0;
this.lastModifiedHeaderSet = false;
this.cacheControlHeader = null;
}
@Override
public void setDateHeader(String name, long date) {
super.setDateHeader(name, date);
if (HEADER_LAST_MODIFIED.equalsIgnoreCase(name)) {
this.lastModifiedHeader = date;
this.lastModifiedHeaderSet = true;
}
}
@Override
public void setHeader(String name, String value) {
super.setHeader(name, value);
if (HEADER_CACHE_CONTROL.equalsIgnoreCase(name)) {
this.cacheControlHeader = value;
}
}
public void setWriteResponseBodyStarted(boolean writeResponseBodyStarted) {
this.writeResponseBodyStarted = writeResponseBodyStarted;
}
}
/**
* Wrapping extension of {@link PrintWriter} to trap the
* "Start Write Response Body" event.
*/
public class XPrintWriter extends PrintWriter {
private final PrintWriter out;
private final HttpServletRequest request;
private final XHttpServletResponse response;
public XPrintWriter(PrintWriter out, HttpServletRequest request,
XHttpServletResponse response) {
super(out);
this.out = out;
this.request = request;
this.response = response;
}
@Override
public PrintWriter append(char c) {
fireBeforeWriteResponseBodyEvent();
return out.append(c);
}
@Override
public PrintWriter append(CharSequence csq) {
fireBeforeWriteResponseBodyEvent();
return out.append(csq);
}
@Override
public PrintWriter append(CharSequence csq, int start, int end) {
fireBeforeWriteResponseBodyEvent();
return out.append(csq, start, end);
}
@Override
public void close() {
fireBeforeWriteResponseBodyEvent();
out.close();
}
private void fireBeforeWriteResponseBodyEvent() {
if (!this.response.isWriteResponseBodyStarted()) {
this.response.setWriteResponseBodyStarted(true);
onBeforeWriteResponseBody(request, response);
}
}
@Override
public void flush() {
fireBeforeWriteResponseBodyEvent();
out.flush();
}
@Override
public void print(boolean b) {
fireBeforeWriteResponseBodyEvent();
out.print(b);
}
@Override
public void print(char c) {
fireBeforeWriteResponseBodyEvent();
out.print(c);
}
@Override
public void print(char[] s) {
fireBeforeWriteResponseBodyEvent();
out.print(s);
}
@Override
public void print(double d) {
fireBeforeWriteResponseBodyEvent();
out.print(d);
}
@Override
public void print(float f) {
fireBeforeWriteResponseBodyEvent();
out.print(f);
}
@Override
public void print(int i) {
fireBeforeWriteResponseBodyEvent();
out.print(i);
}
@Override
public void print(long l) {
fireBeforeWriteResponseBodyEvent();
out.print(l);
}
@Override
public void print(Object obj) {
fireBeforeWriteResponseBodyEvent();
out.print(obj);
}
@Override
public void print(String s) {
fireBeforeWriteResponseBodyEvent();
out.print(s);
}
@Override
public PrintWriter printf(Locale l, String format, Object... args) {
fireBeforeWriteResponseBodyEvent();
return out.printf(l, format, args);
}
@Override
public PrintWriter printf(String format, Object... args) {
fireBeforeWriteResponseBodyEvent();
return out.printf(format, args);
}
@Override
public void println() {
fireBeforeWriteResponseBodyEvent();
out.println();
}
@Override
public void println(boolean x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(char x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(char[] x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(double x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(float x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(int x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(long x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(Object x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void println(String x) {
fireBeforeWriteResponseBodyEvent();
out.println(x);
}
@Override
public void write(char[] buf) {
fireBeforeWriteResponseBodyEvent();
out.write(buf);
}
@Override
public void write(char[] buf, int off, int len) {
fireBeforeWriteResponseBodyEvent();
out.write(buf, off, len);
}
@Override
public void write(int c) {
fireBeforeWriteResponseBodyEvent();
out.write(c);
}
@Override
public void write(String s) {
fireBeforeWriteResponseBodyEvent();
out.write(s);
}
@Override
public void write(String s, int off, int len) {
fireBeforeWriteResponseBodyEvent();
out.write(s, off, len);
}
}
/**
* Wrapping extension of {@link ServletOutputStream} to trap the
* "Start Write Response Body" event.
*/
public class XServletOutputStream extends ServletOutputStream {
private final HttpServletRequest request;
private final XHttpServletResponse response;
private final ServletOutputStream servletOutputStream;
public XServletOutputStream(ServletOutputStream servletOutputStream,
HttpServletRequest request, XHttpServletResponse response) {
super();
this.servletOutputStream = servletOutputStream;
this.response = response;
this.request = request;
}
@Override
public void close() throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.close();
}
private void fireOnBeforeWriteResponseBodyEvent() {
if (!this.response.isWriteResponseBodyStarted()) {
this.response.setWriteResponseBodyStarted(true);
onBeforeWriteResponseBody(request, response);
}
}
@Override
public void flush() throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.flush();
}
@Override
public void print(boolean b) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(b);
}
@Override
public void print(char c) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(c);
}
@Override
public void print(double d) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(d);
}
@Override
public void print(float f) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(f);
}
@Override
public void print(int i) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(i);
}
@Override
public void print(long l) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(l);
}
@Override
public void print(String s) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.print(s);
}
@Override
public void println() throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println();
}
@Override
public void println(boolean b) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(b);
}
@Override
public void println(char c) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(c);
}
@Override
public void println(double d) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(d);
}
@Override
public void println(float f) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(f);
}
@Override
public void println(int i) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(i);
}
@Override
public void println(long l) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(l);
}
@Override
public void println(String s) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.println(s);
}
@Override
public void write(byte[] b) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.write(b);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.write(b, off, len);
}
@Override
public void write(int b) throws IOException {
fireOnBeforeWriteResponseBodyEvent();
servletOutputStream.write(b);
}
/**
* TODO SERVLET 3.1
*/
@Override
public boolean isReady() {
return false;
}
/**
* TODO SERVLET 3.1
*/
@Override
public void setWriteListener(WriteListener listener) {
}
}
/**
* {@link Pattern} for a comma delimited string that support whitespace
* characters
*/
private static final Pattern commaSeparatedValuesPattern = Pattern.compile("\\s*,\\s*");
private static final String HEADER_CACHE_CONTROL = "Cache-Control";
private static final String HEADER_EXPIRES = "Expires";
private static final String HEADER_LAST_MODIFIED = "Last-Modified";
// Log must be non-static as loggers are created per class-loader and this
// Filter may be used in multiple class loaders
private final Log log = LogFactory.getLog(ExpiresFilter.class); // must not be static
private static final String PARAMETER_EXPIRES_BY_TYPE = "ExpiresByType";
private static final String PARAMETER_EXPIRES_DEFAULT = "ExpiresDefault";
private static final String PARAMETER_EXPIRES_EXCLUDED_RESPONSE_STATUS_CODES = "ExpiresExcludedResponseStatusCodes";
/**
* Convert a comma delimited list of numbers into an {@code int[]}.
*
* @param commaDelimitedInts
* can be {@code null}
* @return never {@code null} array
*/
protected static int[] commaDelimitedListToIntArray(
String commaDelimitedInts) {
String[] intsAsStrings = commaDelimitedListToStringArray(commaDelimitedInts);
int[] ints = new int[intsAsStrings.length];
for (int i = 0; i < intsAsStrings.length; i++) {
String intAsString = intsAsStrings[i];
try {
ints[i] = Integer.parseInt(intAsString);
} catch (NumberFormatException e) {
throw new RuntimeException(sm.getString("expiresFilter.numberError",
Integer.valueOf(i), commaDelimitedInts));
}
}
return ints;
}
/**
* Convert a given comma delimited list of strings into an array of String
*
* @param commaDelimitedStrings the string to be split
* @return array of patterns (non {@code null})
*/
protected static String[] commaDelimitedListToStringArray(
String commaDelimitedStrings) {
return (commaDelimitedStrings == null || commaDelimitedStrings.length() == 0) ? new String[0]
: commaSeparatedValuesPattern.split(commaDelimitedStrings);
}
/**
* @return {@code true} if the given {@code str} contains the given
* {@code searchStr}.
* @param str String that will be searched
* @param searchStr The substring to search
*/
protected static boolean contains(String str, String searchStr) {
if (str == null || searchStr == null) {
return false;
}
return str.contains(searchStr);
}
/**
* Convert an array of ints into a comma delimited string
* @param ints The int array
* @return a comma separated string
*/
protected static String intsToCommaDelimitedString(int[] ints) {
if (ints == null) {
return "";
}
StringBuilder result = new StringBuilder();
for (int i = 0; i < ints.length; i++) {
result.append(ints[i]);
if (i < (ints.length - 1)) {
result.append(", ");
}
}
return result.toString();
}
/**
* @param str The String to check
* @return {@code true} if the given {@code str} is
* {@code null} or has a zero characters length.
*/
protected static boolean isEmpty(String str) {
return str == null || str.length() == 0;
}
/**
* @param str The String to check
* @return {@code true} if the given {@code str} has at least one
* character (can be a whitespace).
*/
protected static boolean isNotEmpty(String str) {
return !isEmpty(str);
}
/**
* @return {@code true} if the given {@code string} starts with the
* given {@code prefix} ignoring case.
*
* @param string
* can be {@code null}
* @param prefix
* can be {@code null}
*/
protected static boolean startsWithIgnoreCase(String string, String prefix) {
if (string == null || prefix == null) {
return string == null && prefix == null;
}
if (prefix.length() > string.length()) {
return false;
}
return string.regionMatches(true, 0, prefix, 0, prefix.length());
}
/**
* @return the subset of the given {@code str} that is before the first
* occurrence of the given {@code separator}. Return {@code null}
* if the given {@code str} or the given {@code separator} is
* null. Return and empty string if the {@code separator} is empty.
*
* @param str
* can be {@code null}
* @param separator
* can be {@code null}
*/
protected static String substringBefore(String str, String separator) {
if (str == null || str.isEmpty() || separator == null) {
return null;
}
if (separator.isEmpty()) {
return "";
}
int separatorIndex = str.indexOf(separator);
if (separatorIndex == -1) {
return str;
}
return str.substring(0, separatorIndex);
}
/**
* Default Expires configuration.
*/
private ExpiresConfiguration defaultExpiresConfiguration;
/**
* list of response status code for which the {@link ExpiresFilter} will not
* generate expiration headers.
*/
private int[] excludedResponseStatusCodes = new int[] { HttpServletResponse.SC_NOT_MODIFIED };
/**
* Expires configuration by content type. Visible for test.
*/
private Map expiresConfigurationByContentType = new LinkedHashMap<>();
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
if (request instanceof HttpServletRequest &&
response instanceof HttpServletResponse) {
HttpServletRequest httpRequest = (HttpServletRequest) request;
HttpServletResponse httpResponse = (HttpServletResponse) response;
if (response.isCommitted()) {
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.responseAlreadyCommitted",
httpRequest.getRequestURL()));
}
chain.doFilter(request, response);
} else {
XHttpServletResponse xResponse = new XHttpServletResponse(
httpRequest, httpResponse);
chain.doFilter(request, xResponse);
if (!xResponse.isWriteResponseBodyStarted()) {
// Empty response, manually trigger
// onBeforeWriteResponseBody()
onBeforeWriteResponseBody(httpRequest, xResponse);
}
}
} else {
chain.doFilter(request, response);
}
}
public ExpiresConfiguration getDefaultExpiresConfiguration() {
return defaultExpiresConfiguration;
}
public String getExcludedResponseStatusCodes() {
return intsToCommaDelimitedString(excludedResponseStatusCodes);
}
public int[] getExcludedResponseStatusCodesAsInts() {
return excludedResponseStatusCodes;
}
/**
* Returns the expiration date of the given {@link XHttpServletResponse} or
* {@code null} if no expiration date has been configured for the
* declared content type.
*
* {@code protected} for extension.
*
* @param request The HTTP request
* @param response The wrapped HTTP response
*
* @return the expiration date
* @see HttpServletResponse#getContentType()
*/
protected Date getExpirationDate(HttpServletRequest request, XHttpServletResponse response) {
String contentType = response.getContentType();
if (contentType == null && request != null &&
request.getHttpServletMapping().getMappingMatch() == MappingMatch.DEFAULT &&
response.getStatus() == HttpServletResponse.SC_NOT_MODIFIED) {
// Default servlet normally sets the content type but does not for
// 304 responses. Look it up.
String servletPath = request.getServletPath();
if (servletPath != null) {
int lastSlash = servletPath.lastIndexOf('/');
if (lastSlash > -1) {
String fileName = servletPath.substring(lastSlash + 1);
contentType = request.getServletContext().getMimeType(fileName);
}
}
}
if (contentType != null) {
contentType = contentType.toLowerCase(Locale.ENGLISH);
}
// lookup exact content-type match (e.g.
// "text/html; charset=iso-8859-1")
ExpiresConfiguration configuration = expiresConfigurationByContentType.get(contentType);
if (configuration != null) {
Date result = getExpirationDate(configuration, response);
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.useMatchingConfiguration",
configuration, contentType, contentType, result));
}
return result;
}
if (contains(contentType, ";")) {
// lookup content-type without charset match (e.g. "text/html")
String contentTypeWithoutCharset = substringBefore(contentType, ";").trim();
configuration = expiresConfigurationByContentType.get(contentTypeWithoutCharset);
if (configuration != null) {
Date result = getExpirationDate(configuration, response);
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.useMatchingConfiguration",
configuration, contentTypeWithoutCharset,
contentType, result));
}
return result;
}
}
if (contains(contentType, "/")) {
// lookup major type match (e.g. "text")
String majorType = substringBefore(contentType, "/");
configuration = expiresConfigurationByContentType.get(majorType);
if (configuration != null) {
Date result = getExpirationDate(configuration, response);
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.useMatchingConfiguration",
configuration, majorType, contentType, result));
}
return result;
}
}
if (defaultExpiresConfiguration != null) {
Date result = getExpirationDate(defaultExpiresConfiguration,
response);
if (log.isDebugEnabled()) {
log.debug(sm.getString("expiresFilter.useDefaultConfiguration",
defaultExpiresConfiguration, contentType, result));
}
return result;
}
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.noExpirationConfiguredForContentType",
contentType));
}
return null;
}
/**
*
* Returns the expiration date of the given {@link ExpiresConfiguration},
* {@link HttpServletRequest} and {@link XHttpServletResponse}.
*
*
* {@code protected} for extension.
*
* @param configuration The parsed expires
* @param response The Servlet response
* @return the expiration date
*/
protected Date getExpirationDate(ExpiresConfiguration configuration,
XHttpServletResponse response) {
Calendar calendar;
switch (configuration.getStartingPoint()) {
case ACCESS_TIME:
calendar = Calendar.getInstance();
break;
case LAST_MODIFICATION_TIME:
if (response.isLastModifiedHeaderSet()) {
try {
long lastModified = response.getLastModifiedHeader();
calendar = Calendar.getInstance();
calendar.setTimeInMillis(lastModified);
} catch (NumberFormatException e) {
// default to now
calendar = Calendar.getInstance();
}
} else {
// Last-Modified header not found, use now
calendar = Calendar.getInstance();
}
break;
default:
throw new IllegalStateException(sm.getString(
"expiresFilter.unsupportedStartingPoint",
configuration.getStartingPoint()));
}
for (Duration duration : configuration.getDurations()) {
calendar.add(duration.getUnit().getCalendardField(),
duration.getAmount());
}
return calendar.getTime();
}
public Map getExpiresConfigurationByContentType() {
return expiresConfigurationByContentType;
}
@Override
protected Log getLogger() {
return log;
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
for (Enumeration names = filterConfig.getInitParameterNames(); names.hasMoreElements();) {
String name = names.nextElement();
String value = filterConfig.getInitParameter(name);
try {
if (name.startsWith(PARAMETER_EXPIRES_BY_TYPE)) {
String contentType = name.substring(
PARAMETER_EXPIRES_BY_TYPE.length()).trim().toLowerCase(Locale.ENGLISH);
ExpiresConfiguration expiresConfiguration = parseExpiresConfiguration(value);
this.expiresConfigurationByContentType.put(contentType,
expiresConfiguration);
} else if (name.equalsIgnoreCase(PARAMETER_EXPIRES_DEFAULT)) {
ExpiresConfiguration expiresConfiguration = parseExpiresConfiguration(value);
this.defaultExpiresConfiguration = expiresConfiguration;
} else if (name.equalsIgnoreCase(PARAMETER_EXPIRES_EXCLUDED_RESPONSE_STATUS_CODES)) {
this.excludedResponseStatusCodes = commaDelimitedListToIntArray(value);
} else {
log.warn(sm.getString(
"expiresFilter.unknownParameterIgnored", name,
value));
}
} catch (RuntimeException e) {
throw new ServletException(sm.getString(
"expiresFilter.exceptionProcessingParameter", name,
value), e);
}
}
log.debug(sm.getString("expiresFilter.filterInitialized",
this.toString()));
}
/**
*
* {@code protected} for extension.
*
* @param request The Servlet request
* @param response The Servlet response
* @return true if an expire header may be added
*/
protected boolean isEligibleToExpirationHeaderGeneration(
HttpServletRequest request, XHttpServletResponse response) {
boolean expirationHeaderHasBeenSet = response.containsHeader(HEADER_EXPIRES) ||
contains(response.getCacheControlHeader(), "max-age");
if (expirationHeaderHasBeenSet) {
if (log.isDebugEnabled()) {
log.debug(sm.getString(
"expiresFilter.expirationHeaderAlreadyDefined",
request.getRequestURI(),
Integer.valueOf(response.getStatus()),
response.getContentType()));
}
return false;
}
for (int skippedStatusCode : this.excludedResponseStatusCodes) {
if (response.getStatus() == skippedStatusCode) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("expiresFilter.skippedStatusCode",
request.getRequestURI(),
Integer.valueOf(response.getStatus()),
response.getContentType()));
}
return false;
}
}
return true;
}
/**
*
* If no expiration header has been set by the servlet and an expiration has
* been defined in the {@link ExpiresFilter} configuration, sets the
* '{@code Expires}' header and the attribute '{@code max-age}' of the
* '{@code Cache-Control}' header.
*
*
* Must be called on the "Start Write Response Body" event.
*
*
* Invocations to {@code Logger.debug(...)} are guarded by
* {@link Log#isDebugEnabled()} because
* {@link HttpServletRequest#getRequestURI()} and
* {@link HttpServletResponse#getContentType()} costs {@code String}
* objects instantiations (as of Tomcat 7).
*
* @param request The Servlet request
* @param response The Servlet response
*/
public void onBeforeWriteResponseBody(HttpServletRequest request,
XHttpServletResponse response) {
if (!isEligibleToExpirationHeaderGeneration(request, response)) {
return;
}
Date expirationDate = getExpirationDate(request, response);
if (expirationDate == null) {
if (log.isDebugEnabled()) {
log.debug(sm.getString("expiresFilter.noExpirationConfigured",
request.getRequestURI(),
Integer.valueOf(response.getStatus()),
response.getContentType()));
}
} else {
if (log.isDebugEnabled()) {
log.debug(sm.getString("expiresFilter.setExpirationDate",
request.getRequestURI(),
Integer.valueOf(response.getStatus()),
response.getContentType(), expirationDate));
}
String maxAgeDirective = "max-age=" +
((expirationDate.getTime() - System.currentTimeMillis()) / 1000);
String cacheControlHeader = response.getCacheControlHeader();
String newCacheControlHeader = (cacheControlHeader == null) ? maxAgeDirective
: cacheControlHeader + ", " + maxAgeDirective;
response.setHeader(HEADER_CACHE_CONTROL, newCacheControlHeader);
response.setDateHeader(HEADER_EXPIRES, expirationDate.getTime());
}
}
/**
* Parse configuration lines like
* '{@code access plus 1 month 15 days 2 hours}' or
* '{@code modification 1 day 2 hours 5 seconds}'
*
* @param inputLine the input
* @return the parsed expires
*/
protected ExpiresConfiguration parseExpiresConfiguration(String inputLine) {
String line = inputLine.trim();
StringTokenizer tokenizer = new StringTokenizer(line, " ");
String currentToken;
try {
currentToken = tokenizer.nextToken();
} catch (NoSuchElementException e) {
throw new IllegalStateException(sm.getString(
"expiresFilter.startingPointNotFound", line));
}
StartingPoint startingPoint;
if ("access".equalsIgnoreCase(currentToken) ||
"now".equalsIgnoreCase(currentToken)) {
startingPoint = StartingPoint.ACCESS_TIME;
} else if ("modification".equalsIgnoreCase(currentToken)) {
startingPoint = StartingPoint.LAST_MODIFICATION_TIME;
} else if (!tokenizer.hasMoreTokens() &&
startsWithIgnoreCase(currentToken, "a")) {
startingPoint = StartingPoint.ACCESS_TIME;
// trick : convert duration configuration from old to new style
tokenizer = new StringTokenizer(currentToken.substring(1) +
" seconds", " ");
} else if (!tokenizer.hasMoreTokens() &&
startsWithIgnoreCase(currentToken, "m")) {
startingPoint = StartingPoint.LAST_MODIFICATION_TIME;
// trick : convert duration configuration from old to new style
tokenizer = new StringTokenizer(currentToken.substring(1) +
" seconds", " ");
} else {
throw new IllegalStateException(sm.getString(
"expiresFilter.startingPointInvalid", currentToken, line));
}
try {
currentToken = tokenizer.nextToken();
} catch (NoSuchElementException e) {
throw new IllegalStateException(sm.getString(
"expiresFilter.noDurationFound", line));
}
if ("plus".equalsIgnoreCase(currentToken)) {
// skip
try {
currentToken = tokenizer.nextToken();
} catch (NoSuchElementException e) {
throw new IllegalStateException(sm.getString(
"expiresFilter.noDurationFound", line));
}
}
List durations = new ArrayList<>();
while (currentToken != null) {
int amount;
try {
amount = Integer.parseInt(currentToken);
} catch (NumberFormatException e) {
throw new IllegalStateException(sm.getString(
"expiresFilter.invalidDurationNumber",
currentToken, line));
}
try {
currentToken = tokenizer.nextToken();
} catch (NoSuchElementException e) {
throw new IllegalStateException(
sm.getString(
"expiresFilter.noDurationUnitAfterAmount",
Integer.valueOf(amount), line));
}
DurationUnit durationUnit;
if ("year".equalsIgnoreCase(currentToken) ||
"years".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.YEAR;
} else if ("month".equalsIgnoreCase(currentToken) ||
"months".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.MONTH;
} else if ("week".equalsIgnoreCase(currentToken) ||
"weeks".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.WEEK;
} else if ("day".equalsIgnoreCase(currentToken) ||
"days".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.DAY;
} else if ("hour".equalsIgnoreCase(currentToken) ||
"hours".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.HOUR;
} else if ("minute".equalsIgnoreCase(currentToken) ||
"minutes".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.MINUTE;
} else if ("second".equalsIgnoreCase(currentToken) ||
"seconds".equalsIgnoreCase(currentToken)) {
durationUnit = DurationUnit.SECOND;
} else {
throw new IllegalStateException(
sm.getString(
"expiresFilter.invalidDurationUnit",
currentToken, line));
}
Duration duration = new Duration(amount, durationUnit);
durations.add(duration);
if (tokenizer.hasMoreTokens()) {
currentToken = tokenizer.nextToken();
} else {
currentToken = null;
}
}
return new ExpiresConfiguration(startingPoint, durations);
}
public void setDefaultExpiresConfiguration(
ExpiresConfiguration defaultExpiresConfiguration) {
this.defaultExpiresConfiguration = defaultExpiresConfiguration;
}
public void setExcludedResponseStatusCodes(int[] excludedResponseStatusCodes) {
this.excludedResponseStatusCodes = excludedResponseStatusCodes;
}
public void setExpiresConfigurationByContentType(
Map expiresConfigurationByContentType) {
this.expiresConfigurationByContentType = expiresConfigurationByContentType;
}
@Override
public String toString() {
return getClass().getSimpleName() + "[excludedResponseStatusCode=[" +
intsToCommaDelimitedString(this.excludedResponseStatusCodes) +
"], default=" + this.defaultExpiresConfiguration + ", byType=" +
this.expiresConfigurationByContentType + "]";
}
}