/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.staticexport;
import org.opencms.file.CmsObject;
/**
* Allows to configure customized link substitution behavior.<p>
*
* This handler is plugged into
* {@link CmsLinkManager#substituteLink(org.opencms.file.CmsObject, String, String, boolean)},
* which is the central method to calculate links for the use on web pages.
* This method is also used by the <code><cms:link /></code> tag.<p>
*
* Moreover, this handler is plugged into
* {@link CmsLinkManager#getRootPath(CmsObject, String, String)},
* which basically is the revered method that gets a VFS root path from a link.<p>
*
* For the implementation, you must implement the methods in this interface so that:<pre>
* String path; // assume we have a valid VFS resource root path
* CmsObject cms; // assume we have a valid OpenCms user context
* CmsLinkManager lm = OpenCms.getLinkManager();
* String link = lm.substituteLinkForRootPath(cms, path);
* String rootPath = lm.getRootPath(cms, link);
* link.equals(rootPath); // this must be true!</pre>
*
* Using this handler, you can completely customize the behavior of the link substitution.<p>
*
* The default implementation of this interface is {@link CmsDefaultLinkSubstitutionHandler}.<p>
*
* @since 7.0.2
*
* @see CmsLinkManager#substituteLink(org.opencms.file.CmsObject, String, String, boolean)
* for the method where this handler is used to create a link from a VFS root path
* @see CmsLinkManager#getRootPath(CmsObject, String, String)
* for the method where this handler is used to create VFS root path from a link
*
* @see CmsDefaultLinkSubstitutionHandler
* for the default implementation of this interface
*/
public interface I_CmsLinkSubstitutionHandler {
/**
* Returns a link <i>from</i> the URI stored in the provided OpenCms user context
* <i>to</i> the VFS resource indicated by the given <code>link</code> and <code>siteRoot</code>,
* for use on web pages.<p>
*
* The result should be an absolute link that contains the configured context path and
* servlet name, and in the case of the "online" project it will also be rewritten according to
* to the configured static export settings.<p>
*
* In case <code>link</code> is a relative URI, the current URI contained in the provided
* OpenCms user context <code>cms</code> is normally used to make the relative <code>link</code> absolute.<p>
*
* The provided <code>siteRoot</code> is assumed to be the "home" of the link.
* In case the current site of the given OpenCms user context <code>cms</code> is different from the
* provided <code>siteRoot</code>, the full server prefix is appended to the result link.<p>
*
* A server prefix is also added if
* <ul>
* <li>the link is contained in a normal document and the link references a secure document</li>
* <li>the link is contained in a secure document and the link references a normal document</li>
* </ul>
*
* Please note the above text describes the default behavior as implemented by
* {@link CmsDefaultLinkSubstitutionHandler}, which can be fully customized using this handler interface.<p>
*
* @param cms the current OpenCms user context
* @param link the link to process which is assumed to point to a VFS resource, with optional parameters
* @param siteRoot the site root of the <code>link</code>
* @param forceSecure if <code>true</code> generates always an absolute URL (with protocol and server name) for secure links
*
* @return a link <i>from</i> the URI stored in the provided OpenCms user context
* <i>to</i> the VFS resource indicated by the given <code>link</code> and <code>siteRoot</code>
*
* @see #getRootPath(CmsObject, String, String) for the reverse function, which creates a VFS
*/
String getLink(CmsObject cms, String link, String siteRoot, boolean forceSecure);
/**
* Returns the resource root path in the OpenCms VFS for the given target URI link, or <code>null</code> in
* case the link points to an external site.<p>
*
* The default implementation applies the following transformations to the link:<ul>
* <li>In case the link starts with a VFS prefix (for example <code>/opencms/opencms</code>,
* this prefix is removed from the result
* <li>In case the link is not a root path, the current site root is appended to the result.<p>
* <li>In case the link is relative, it will be made absolute using the given absolute <code>basePath</code>
* as starting point.<p>
* <li>In case the link contains a server schema (for example <code>http://www.mysite.de/</code>),
* which points to a configured site in OpenCms, the server schema is replaced with
* the root path of the site.<p>
* <li>In case the link points to an external site, or in case it is not a valid URI,
* then <code>null</code> is returned.<p>
* </ul>
*
* Please note the above text describes the default behavior as implemented by
* {@link CmsDefaultLinkSubstitutionHandler}, which can be fully customized using this handler interface.<p>
*
* @param cms the current users OpenCms context
* @param targetUri the target URI link
* @param basePath path to use as base in case the target URI is relative (can be <code>null</code>)
*
* @return the resource root path in the OpenCms VFS for the given target URI link, or <code>null</code> in
* case the link points to an external site
*
* @see #getLink(CmsObject, String, String, boolean) for the reverse function, which creates a link
* form a VFS resource path
*/
String getRootPath(CmsObject cms, String targetUri, String basePath);
}