CanonicalUrlService.java
/*
* Copyright (c) 2002-2020, City of Paris
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright notice
* and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice
* and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. Neither the name of 'Mairie de Paris' nor 'Lutece' nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* License 1.0
*/
package fr.paris.lutece.plugins.seo.service;
import fr.paris.lutece.portal.service.datastore.DatastoreService;
import fr.paris.lutece.portal.service.util.AppLogService;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
/**
* Canonical Url Service
*/
public final class CanonicalUrlService
{
private static final String HEAD = "<head>";
private static final String COMMENT = "\n\t\t<!-- Canonical URL added by SEO plugin --> ";
private static final String CANONICAL_TAG_BEGIN = "\n\t\t<link rel=\"canonical\" href=\"";
private static final String CANONICAL_TAG_END = "\" />\n";
private static CanonicalUrlService _singleton = new CanonicalUrlService( );
private static boolean _bCanonical;
/**
* Private constructor
*/
private CanonicalUrlService( )
{
_bCanonical = DatastoreService.getDataValue( SEODataKeys.KEY_CANONICAL_URLS_ENABLED, "" ).equals( DatastoreService.VALUE_TRUE );
}
/**
* Return the unique instance
*
* @return The instance
*/
public static synchronized CanonicalUrlService instance( )
{
return _singleton;
}
/**
* Tells if canonical urls are enabled
*
* @return True if canonical urls are enabled, otherwise false
*/
public boolean isCanonicalUrlsEnabled( )
{
return _bCanonical;
}
/**
* Sets the status of Canonical URLs (Enabled or Disabled)
*
* @param bEnabled
* The status
*/
public void setCanonicalUrlsEnabled( boolean bEnabled )
{
_bCanonical = bEnabled;
}
/**
* Add canonical URL into an HTML page's content
*
* @param strContent
* The HTML page's content
* @param request
* The HTTP request
* @param mapFriendlyUrls
* The map of friendly URLS
* @param strBaseUrl
* The Base URL
* @return The HTML page content with the canonical URL inserted
*/
public String addCanonicalUrl( String strContent, HttpServletRequest request, Map<String, String> mapFriendlyUrls, String strBaseUrl )
{
StringBuilder sbUrl = new StringBuilder( );
sbUrl.append( request.getRequestURI( ).substring( request.getContextPath( ).length( ) + 1 ) );
sbUrl.append( "?" ).append( request.getQueryString( ) );
String strFriendlyUrl = mapFriendlyUrls.get( sbUrl.toString( ) );
if ( strFriendlyUrl != null )
{
return insertCanonicalUrl( strContent, strBaseUrl + strFriendlyUrl );
}
return strContent;
}
/**
* Add canonical URL into an HTML page's content
*
* @param strContent
* The HTML page's content
* @param strUrl
* The canonical URL to insert
* @return The HTML page content with the canonical URL inserted
*/
private String insertCanonicalUrl( String strContent, String strUrl )
{
StringBuilder sb = new StringBuilder( );
int nPos = strContent.indexOf( HEAD );
if ( nPos < 0 )
{
AppLogService.error( "CanonicalUrl Service : no HEAD tag found in " + strUrl );
return strContent;
}
sb.append( strContent.substring( 0, nPos + HEAD.length( ) ) );
sb.append( COMMENT );
sb.append( CANONICAL_TAG_BEGIN );
sb.append( strUrl );
sb.append( CANONICAL_TAG_END );
sb.append( strContent.substring( nPos + HEAD.length( ) ) );
return sb.toString( );
}
}