/*
* $Id$
*
* 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.struts2.dispatcher;
import java.io.InputStream;
import java.io.OutputStream;
import javax.servlet.http.HttpServletResponse;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import com.opensymphony.xwork2.util.ValueStack;
/**
* <!-- START SNIPPET: description -->
*
* A custom Result type for sending raw data (via an InputStream) directly to the
* HttpServletResponse. Very useful for allowing users to download content.
*
* <!-- END SNIPPET: description -->
* <p/>
* <b>This result type takes the following parameters:</b>
*
* <!-- START SNIPPET: params -->
*
* <ul>
*
* <li><b>contentType</b> - the stream mime-type as sent to the web browser
* (default = <code>text/plain</code>).</li>
*
* <li><b>contentLength</b> - the stream length in bytes (the browser displays a
* progress bar).</li>
*
* <li><b>contentDisposition</b> - the content disposition header value for
* specifing the file name (default = <code>inline</code>, values are typically
* <i>attachment;filename="document.pdf"</i>.</li>
*
* <li><b>inputName</b> - the name of the InputStream property from the chained
* action (default = <code>inputStream</code>).</li>
*
* <li><b>bufferSize</b> - the size of the buffer to copy from input to output
* (default = <code>1024</code>).</li>
*
* <li><b>allowCaching</b> if set to 'false' it will set the headers 'Pragma' and 'Cache-Control'
* to 'no-cahce', and prevent client from caching the content. (default = <code>true</code>)
*
* <li><b>contentCharSet</b> if set to a string, ';charset=value' will be added to the
* content-type header, where value is the string set. If set to an expression, the result
* of evaluating the expression will be used. If not set, then no charset will be set on
* the header</li>
* </ul>
*
* <p>These parameters can also be set by exposing a similarly named getter method on your Action. For example, you can
* provide <code>getContentType()</code> to override that parameter for the current action.</p>
*
* <!-- END SNIPPET: params -->
*
* <b>Example:</b>
*
* <pre><!-- START SNIPPET: example -->
* <result name="success" type="stream">
* <param name="contentType">image/jpeg</param>
* <param name="inputName">imageStream</param>
* <param name="contentDisposition">attachment;filename="document.pdf"</param>
* <param name="bufferSize">1024</param>
* </result>
* <!-- END SNIPPET: example --></pre>
*
*/
public class StreamResult extends StrutsResultSupport {
private static final long serialVersionUID = -1468409635999059850L;
protected static final Logger LOG = LoggerFactory.getLogger(StreamResult.class);
public static final String DEFAULT_PARAM = "inputName";
protected String contentType = "text/plain";
protected String contentLength;
protected String contentDisposition = "inline";
protected String contentCharSet ;
protected String inputName = "inputStream";
protected InputStream inputStream;
protected int bufferSize = 1024;
protected boolean allowCaching = true;
public StreamResult() {
super();
}
public StreamResult(InputStream in) {
this.inputStream = in;
}
/**
* @return Returns the whether or not the client should be requested to allow caching of the data stream.
*/
public boolean getAllowCaching() {
return allowCaching;
}
/**
* Set allowCaching to <tt>false</tt> to indicate that the client should be requested not to cache the data stream.
* This is set to <tt>false</tt> by default
*
* @param allowCaching Enable caching.
*/
public void setAllowCaching(boolean allowCaching) {
this.allowCaching = allowCaching;
}
/**
* @return Returns the bufferSize.
*/
public int getBufferSize() {
return (bufferSize);
}
/**
* @param bufferSize The bufferSize to set.
*/
public void setBufferSize(int bufferSize) {
this.bufferSize = bufferSize;
}
/**
* @return Returns the contentType.
*/
public String getContentType() {
return (contentType);
}
/**
* @param contentType The contentType to set.
*/
public void setContentType(String contentType) {
this.contentType = contentType;
}
/**
* @return Returns the contentLength.
*/
public String getContentLength() {
return contentLength;
}
/**
* @param contentLength The contentLength to set.
*/
public void setContentLength(String contentLength) {
this.contentLength = contentLength;
}
/**
* @return Returns the Content-disposition header value.
*/
public String getContentDisposition() {
return contentDisposition;
}
/**
* @param contentDisposition the Content-disposition header value to use.
*/
public void setContentDisposition(String contentDisposition) {
this.contentDisposition = contentDisposition;
}
/**
* @return Returns the charset specified by the user
*/
public String getContentCharSet() {
return contentCharSet;
}
/**
* @param contentCharSet the charset to use on the header when sending the stream
*/
public void setContentCharSet(String contentCharSet) {
this.contentCharSet = contentCharSet;
}
/**
* @return Returns the inputName.
*/
public String getInputName() {
return (inputName);
}
/**
* @param inputName The inputName to set.
*/
public void setInputName(String inputName) {
this.inputName = inputName;
}
/**
* @see org.apache.struts2.dispatcher.StrutsResultSupport#doExecute(java.lang.String, com.opensymphony.xwork2.ActionInvocation)
*/
protected void doExecute(String finalLocation, ActionInvocation invocation) throws Exception {
// Override any parameters using values on the stack
resolveParamsFromStack(invocation.getStack(), invocation);
OutputStream oOutput = null;
try {
if (inputStream == null) {
// Find the inputstream from the invocation variable stack
inputStream = (InputStream) invocation.getStack().findValue(conditionalParse(inputName, invocation));
}
if (inputStream == null) {
String msg = ("Can not find a java.io.InputStream with the name [" + inputName + "] in the invocation stack. " +
"Check the <param name=\"inputName\"> tag specified for this action.");
LOG.error(msg);
throw new IllegalArgumentException(msg);
}
// Find the Response in context
HttpServletResponse oResponse = (HttpServletResponse) invocation.getInvocationContext().get(HTTP_RESPONSE);
// Set the content type
if (contentCharSet != null && ! contentCharSet.equals("")) {
oResponse.setContentType(conditionalParse(contentType, invocation)+";charset="+contentCharSet);
}
else {
oResponse.setContentType(conditionalParse(contentType, invocation));
}
// Set the content length
if (contentLength != null) {
String _contentLength = conditionalParse(contentLength, invocation);
int _contentLengthAsInt = -1;
try {
_contentLengthAsInt = Integer.parseInt(_contentLength);
if (_contentLengthAsInt >= 0) {
oResponse.setContentLength(_contentLengthAsInt);
}
}
catch(NumberFormatException e) {
if (LOG.isWarnEnabled()) {
LOG.warn("failed to recongnize "+_contentLength+" as a number, contentLength header will not be set", e);
}
}
}
// Set the content-disposition
if (contentDisposition != null) {
oResponse.addHeader("Content-Disposition", conditionalParse(contentDisposition, invocation));
}
// Set the cache control headers if neccessary
if (!allowCaching) {
oResponse.addHeader("Pragma", "no-cache");
oResponse.addHeader("Cache-Control", "no-cache");
}
// Get the outputstream
oOutput = oResponse.getOutputStream();
if (LOG.isDebugEnabled()) {
LOG.debug("Streaming result [" + inputName + "] type=[" + contentType + "] length=[" + contentLength +
"] content-disposition=[" + contentDisposition + "] charset=[" + contentCharSet + "]");
}
// Copy input to output
if (LOG.isDebugEnabled()) {
LOG.debug("Streaming to output buffer +++ START +++");
}
byte[] oBuff = new byte[bufferSize];
int iSize;
while (-1 != (iSize = inputStream.read(oBuff))) {
oOutput.write(oBuff, 0, iSize);
}
if (LOG.isDebugEnabled()) {
LOG.debug("Streaming to output buffer +++ END +++");
}
// Flush
oOutput.flush();
}
finally {
if (inputStream != null) inputStream.close();
if (oOutput != null) oOutput.close();
}
}
/**
* Tries to lookup the parameters on the stack. Will override any existing parameters
*
* @param stack The current value stack
*/
protected void resolveParamsFromStack(ValueStack stack, ActionInvocation invocation) {
String disposition = stack.findString("contentDisposition");
if (disposition != null) {
setContentDisposition(disposition);
}
String contentType = stack.findString("contentType");
if (contentType != null) {
setContentType(contentType);
}
String inputName = stack.findString("inputName");
if (inputName != null) {
setInputName(inputName);
}
String contentLength = stack.findString("contentLength");
if (contentLength != null) {
setContentLength(contentLength);
}
Integer bufferSize = (Integer) stack.findValue("bufferSize", Integer.class);
if (bufferSize != null) {
setBufferSize(bufferSize.intValue());
}
if (contentCharSet != null ) {
contentCharSet = conditionalParse(contentCharSet, invocation);
}
else {
contentCharSet = stack.findString("contentCharSet");
}
}
}