org.sakaiproject.sdata.tool.util.PathSecurityAssertion.java Source code

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Here is the source code for org.sakaiproject.sdata.tool.util.PathSecurityAssertion.java

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/*
 * Licensed to the Sakai Foundation (SF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The SF 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.sakaiproject.sdata.tool.util;

import com.google.inject.Inject;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.sakaiproject.kernel.api.authz.AuthzResolverService;
import org.sakaiproject.kernel.api.authz.PermissionQuery;
import org.sakaiproject.sdata.tool.api.SDataException;
import org.sakaiproject.sdata.tool.api.SecurityAssertion;

import java.util.Map;

import javax.servlet.http.HttpServletResponse;

/**
 * <p>
 * An implementation of the Security Assertion that uses the http method, the
 * path and the sakai security service for perform the assertion. On check it
 * will throw SDataExceptions indicating forbidden if the path is outside its
 * configured range, or it is denied by the the Sakai security service.
 * </p>
 * <p>
 * 
 * It accepts paths starting with basePath, and then replaces basePath with
 * baseResource before checking for the method with the resulting path and the
 * PermissionQuery associated with the method.
 * </p>
 * 
 * @author ieb
 */
public class PathSecurityAssertion implements SecurityAssertion {

    private static final Log LOG = LogFactory.getLog(PathSecurityAssertion.class);

    /**
     * The base location that is Security Advisor applies to. Only paths that
     * start with this are allowed all others are denied regardless of the method.
     * If the path starts with baseLocation, baseLocation is removed from the path
     * and baseResource is prepended to the patch to generate a full resource
     * location suitable for using with the security service.
     */
    private String basePath;

    /**
     * A map mapping http methods to locks
     */
    private Map<String, PermissionQuery> locks;

    /**
     * this is prepended to the resource path, after normalizing (ie removing
     * baseLocation) and before sending to the Sakai security service.
     */
    private String baseResource;

    /**
     * The AuthzResolverService performs the resolution of security assertions
     * once the path and method have been translated into a permissions query and
     * a resource path.
     */
    private AuthzResolverService authzResolverService;

    /**
     */
    @Inject
    public PathSecurityAssertion(AuthzResolverService authzResolverService) {
        this.authzResolverService = authzResolverService;
    }

    /**
     * @param basePath
     *          the baseUrl to set, this it the stub of the url coming into the
     *          assertion that will be handled by this assertion
     */
    public void setBasePath(String basePath) {
        this.basePath = basePath;
    }

    /**
     * @param baseResource
     *          the baseResource, having remove the base URL from the url coming
     *          in, the base resource is added to generate the path in the
     *          repository on which the assertion is made.
     */
    public void setBaseResource(String baseResource) {
        this.baseResource = baseResource;
    }

    /**
     * @param locks
     *          locks provide a translation between the method being used on the
     *          url GET, POST, PUT etc and the permission that will be required to
     *          pass the assertion. Against each method there is a PermissionQuery
     *          that, if matching should be satisfied for the permission to be
     *          granted.
     */
    public void setLocks(Map<String, PermissionQuery> locks) {
        this.locks = locks;
    }

    /**
     * Performs the security assertion based on the resourceLocation, from the
     * original request and the method begin attempted. Will throw a
     * SDataException with Forbidden if the resource location is outside the
     * configured range, or if permission is denied.
     * 
     * @param method
     *          the http method being used
     * @param urlPath
     *          the path of the url, excluding host, protocol, port and query
     *          string, but including everything else.
     * @see org.sakaiproject.sdata.tool.api.SecurityAssertion#check(java.lang.String,java.lang.String,
     *      java.lang.String)
     */
    public void check(String method, String resourcePath) throws SDataException {

        if (!(basePath.length() == 0) && (resourcePath == null || !resourcePath.startsWith(basePath))) {
            LOG.info("Denied " + method + " on [" + resourcePath + "] base mismatch [" + basePath + "]");
            throw new SDataException(HttpServletResponse.SC_FORBIDDEN, "Access Forbidden");
        }
        String resourceReference = baseResource + resourcePath.substring(basePath.length());
        PermissionQuery permissionQuery = getResourceLock(method);

        if (permissionQuery == null) {
            throw new SDataException(HttpServletResponse.SC_METHOD_NOT_ALLOWED,
                    "Method " + method + " is not allowed");
        } else {
            authzResolverService.check(resourceReference, permissionQuery);
        }
    }

    /**
     * Convert the HTTP Method into a lock.
     * 
     * @param method
     * @return
     */
    protected PermissionQuery getResourceLock(String method) {
        return locks.get(method);
    }

}