org.springframework.web.util.ContentCachingResponseWrapper Maven / Gradle / Ivy
/*
* Copyright 2002-2015 the original author or authors.
*
* 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.
*/
package org.springframework.web.util;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import org.springframework.util.ResizableByteArrayOutputStream;
import org.springframework.util.StreamUtils;
/**
* {@link javax.servlet.http.HttpServletResponse} wrapper that caches all content written to
* the {@linkplain #getOutputStream() output stream} and {@linkplain #getWriter() writer},
* and allows this content to be retrieved via a {@link #getContentAsByteArray() byte array}.
*
* Used e.g. by {@link org.springframework.web.filter.ShallowEtagHeaderFilter}.
*
* @author Juergen Hoeller
* @since 4.1.3
* @see ContentCachingRequestWrapper
*/
public class ContentCachingResponseWrapper extends HttpServletResponseWrapper {
private final ResizableByteArrayOutputStream content = new ResizableByteArrayOutputStream(1024);
private final ServletOutputStream outputStream = new ResponseServletOutputStream();
private PrintWriter writer;
private int statusCode = HttpServletResponse.SC_OK;
private Integer contentLength;
/**
* Create a new ContentCachingResponseWrapper for the given servlet response.
* @param response the original servlet response
*/
public ContentCachingResponseWrapper(HttpServletResponse response) {
super(response);
}
@Override
public void setStatus(int sc) {
super.setStatus(sc);
this.statusCode = sc;
}
@SuppressWarnings("deprecation")
@Override
public void setStatus(int sc, String sm) {
super.setStatus(sc, sm);
this.statusCode = sc;
}
@Override
public void sendError(int sc) throws IOException {
copyBodyToResponse();
try {
super.sendError(sc);
}
catch (IllegalStateException ex) {
// Possibly on Tomcat when called too late: fall back to silent setStatus
super.setStatus(sc);
}
this.statusCode = sc;
}
@Override
@SuppressWarnings("deprecation")
public void sendError(int sc, String msg) throws IOException {
copyBodyToResponse();
try {
super.sendError(sc, msg);
}
catch (IllegalStateException ex) {
// Possibly on Tomcat when called too late: fall back to silent setStatus
super.setStatus(sc, msg);
}
this.statusCode = sc;
}
@Override
public void sendRedirect(String location) throws IOException {
copyBodyToResponse();
super.sendRedirect(location);
}
@Override
public ServletOutputStream getOutputStream() {
return this.outputStream;
}
@Override
public PrintWriter getWriter() throws IOException {
if (this.writer == null) {
String characterEncoding = getCharacterEncoding();
this.writer = (characterEncoding != null ? new ResponsePrintWriter(characterEncoding) :
new ResponsePrintWriter(WebUtils.DEFAULT_CHARACTER_ENCODING));
}
return this.writer;
}
@Override
public void setContentLength(int len) {
if (len > this.content.capacity()) {
this.content.resize(len);
}
this.contentLength = len;
}
// Overrides Servlet 3.1 setContentLengthLong(long) at runtime
public void setContentLengthLong(long len) {
if (len > Integer.MAX_VALUE) {
throw new IllegalArgumentException("Content-Length exceeds ShallowEtagHeaderFilter's maximum (" +
Integer.MAX_VALUE + "): " + len);
}
int lenInt = (int) len;
if (lenInt > this.content.capacity()) {
this.content.resize(lenInt);
}
this.contentLength = lenInt;
}
@Override
public void setBufferSize(int size) {
if (size > this.content.capacity()) {
this.content.resize(size);
}
}
@Override
public void resetBuffer() {
this.content.reset();
}
@Override
public void reset() {
super.reset();
this.content.reset();
}
/**
* Return the status code as specified on the response.
*/
public int getStatusCode() {
return this.statusCode;
}
/**
* Return the cached response content as a byte array.
*/
public byte[] getContentAsByteArray() {
return this.content.toByteArray();
}
private void copyBodyToResponse() throws IOException {
if (this.content.size() > 0) {
if (this.contentLength != null) {
getResponse().setContentLength(this.contentLength);
this.contentLength = null;
}
StreamUtils.copy(this.content.toByteArray(), getResponse().getOutputStream());
this.content.reset();
}
}
private class ResponseServletOutputStream extends ServletOutputStream {
@Override
public void write(int b) throws IOException {
content.write(b);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
content.write(b, off, len);
}
}
private class ResponsePrintWriter extends PrintWriter {
public ResponsePrintWriter(String characterEncoding) throws UnsupportedEncodingException {
super(new OutputStreamWriter(content, characterEncoding));
}
@Override
public void write(char buf[], int off, int len) {
super.write(buf, off, len);
super.flush();
}
@Override
public void write(String s, int off, int len) {
super.write(s, off, len);
super.flush();
}
@Override
public void write(int c) {
super.write(c);
super.flush();
}
}
}