/*!
* Copyright 2010 - 2013 Pentaho Corporation. All rights reserved.
*
* 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.pentaho.platform.web.http.filters;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import java.io.IOException;
/**
* <p>
* Example filter that sets the character encoding to be used in parsing the incoming request, either unconditionally or
* only if the client did not specify a character encoding. Configuration of this filter is based on the following
* initialization parameters:
* </p>
* <ul>
* <li><strong>encoding</strong> - The character encoding to be configured for this request, either conditionally or
* unconditionally based on the <code>ignore</code> initialization parameter. This parameter is required, so there is no
* default.</li>
* <li><strong>ignore</strong> - If set to "true", any character encoding specified by the client is ignored, and the
* value returned by the <code>selectEncoding()</code> method is set. If set to "false, <code>selectEncoding()</code> is
* called <strong>only</strong> if the client has not already specified an encoding. By default, this parameter is set
* to "true".</li>
* </ul>
*
* <p>
* Although this filter can be used unchanged, it is also easy to subclass it and make the <code>selectEncoding()</code>
* method more intelligent about what encoding to choose, based on characteristics of the incoming request (such as the
* values of the <code>Accept-Language</code> and <code>User-Agent</code> headers, or a value stashed in the current
* user's session.
* </p>
*
* @author Craig McClanahan
* @version $Revision: 267129 $ $Date: 2004-03-18 11:40:35 -0500 (Thu, 18 Mar 2004) $
*/
public class SetCharacterEncodingFilter implements Filter {
// ----------------------------------------------------- Instance Variables
/**
* The default character encoding to set for requests that pass through this filter.
*/
protected String encoding = null;
/**
* The filter configuration object we are associated with. If this value is null, this filter instance is not
* currently configured.
*/
protected FilterConfig filterConfig = null;
/**
* Should a character encoding specified by the client be ignored?
*/
protected boolean ignore = true;
// --------------------------------------------------------- Public Methods
/**
* Take this filter out of service.
*/
public void destroy() {
this.encoding = null;
this.filterConfig = null;
}
/**
* Select and set (if specified) the character encoding to be used to interpret request parameters for this request.
*
* @param request
* The servlet request we are processing
* @param result
* The servlet response we are creating
* @param chain
* The filter chain we are processing
*
* @exception IOException
* if an input/output error occurs
* @exception ServletException
* if a servlet error occurs
*/
public void doFilter( final ServletRequest request, final ServletResponse response, final FilterChain chain )
throws IOException, ServletException {
// Conditionally select and set the character encoding to be used
if ( ignore || ( request.getCharacterEncoding() == null ) ) {
String localEncoding = selectEncoding( request );
if ( localEncoding != null ) {
request.setCharacterEncoding( localEncoding );
}
}
// Pass control on to the next filter
chain.doFilter( request, response );
}
/**
* Place this filter into service.
*
* @param localFilterConfig
* The filter configuration object
*/
public void init( final FilterConfig localFilterConfig ) throws ServletException {
this.filterConfig = localFilterConfig;
this.encoding = filterConfig.getInitParameter( "encoding" ); //$NON-NLS-1$
String value = filterConfig.getInitParameter( "ignore" ); //$NON-NLS-1$
if ( value == null ) {
this.ignore = true;
} else if ( value.equalsIgnoreCase( "true" ) ) {
this.ignore = true;
} else if ( value.equalsIgnoreCase( "yes" ) ) {
this.ignore = true;
} else {
this.ignore = false;
}
}
// ------------------------------------------------------ Protected Methods
/**
* Select an appropriate character encoding to be used, based on the characteristics of the current request and/or
* filter initialization parameters. If no character encoding should be set, return <code>null</code>.
* <p>
* The default implementation unconditionally returns the value configured by the <strong>encoding</strong>
* initialization parameter for this filter.
*
* @param request
* The servlet request we are processing
*/
protected String selectEncoding( final ServletRequest request ) {
return ( this.encoding );
}
}