package org.fcrepo.server.security.xacml.util;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.fcrepo.common.Constants;
import org.fcrepo.common.MalformedPIDException;
import org.fcrepo.common.PID;
import org.fcrepo.server.security.xacml.pdp.MelcoePDPException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public abstract class RelationshipResolverBase
implements RelationshipResolver {
private static final Logger logger =
LoggerFactory.getLogger(RelationshipResolverBase.class);
/**
* Designates the repository itself. Policies can apply to the repository,
* but it is a special case, as it is not represented by a PID, and by
* definition, has no parents.
*/
protected static final String REPOSITORY = Constants.FEDORA_REPOSITORY_PID.uri;
protected static String DEFAULT_RELATIONSHIP = "info:fedora/fedora-system:def/relations-external#isMemberOf";
// relationships to parent object
protected final List<String> parentRelationships;
// relationships to child object
protected final List<String> childRelationships;
/**
* Constructor that takes a map of parent-child predicates (relationships).
* {@link ContextHandlerImpl} builds the map from the relationship-resolver
* section of config-melcoe-pep.xml (in WEB-INF/classes).
*
* @param options
* @throws MelcoePDPException
*/
public RelationshipResolverBase(Map<String, String> options) {
parentRelationships = new ArrayList<String>();
ArrayList<String> childRels = new ArrayList<String>();
List<String> keys = new ArrayList<String>(options.keySet());
Collections.sort(keys);
for (String s : keys) {
if (s.startsWith("xacml-parent-relationship")) {
parentRelationships.add(options.get(s));
} else if (s.startsWith("xacml-child-relationship")) {
childRels.add(options.get(s));
}
}
// always set a default parent relationship
if (parentRelationships.isEmpty()) {
parentRelationships.add(DEFAULT_RELATIONSHIP);
}
if (childRels.isEmpty()) {
childRelationships = null;
} else {
childRelationships = childRels;
}
}
/**
* given either a ns:pid/ds identifier or an info:fedora/ URI form of the same
* return the URI form, validating the PID part. Returns null if the argument
* was invalid/could not be validated/converted
*
* @param res identifier for fedora resource
* @return URI form
*/
protected String getFedoraResourceURI(String res) {
// strip off info URI part if present
String strippedRes;
if (res.startsWith(Constants.FEDORA.uri)) {
strippedRes = res.substring(Constants.FEDORA.uri.length());
} else {
strippedRes = res;
}
// split into pid + datastream (if present), validate PID and then recombine datastream back in using URI form of PID
String parts[] = strippedRes.split("/");
PID pid;
try {
pid = new PID(parts[0]);
} catch (MalformedPIDException e1) {
logger.warn("Invalid Fedora resource identifier: {}. PID part of URI is malformed", res);
return null;
}
String resURI;
if (parts.length == 1) {
resURI = pid.toURI();
} else if (parts.length == 2) {
resURI = pid.toURI() + "/" + parts[1]; // add datastream ID back
} else {
logger.warn("Invalid Fedora resource identifier: {}. Should be pid or datastream (URI form optional", res);
return null;
}
return resURI;
}
}