Policy.java

/**
 * Licensed to The Apereo Foundation under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 *
 * The Apereo Foundation licenses this file to you under the Educational
 * Community 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://opensource.org/licenses/ecl2.txt
 *
 * 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.opencastproject.urlsigning.common;

import static java.util.Objects.requireNonNull;

import com.google.common.base.Optional;
import com.google.common.net.InetAddresses;

import org.apache.commons.lang3.StringUtils;
import org.joda.time.DateTime;

import java.net.InetAddress;

/**
 * Represents a policy for a signed resource that looks like
 *
 */
public final class Policy {

  /** The base URL for the resource being requested. */
  private final String baseUrl;

  /** The date and time when the resource expires. */
  private final DateTime validUntil;

  /** The date and time when the resource will become available. */
  private final Optional<DateTime> validFrom;

  /** An optional client IP address that made the original request. */
  private final Optional<InetAddress> clientIpAddress;

  /** The required strategy to convert a base url to the resource url. */
  private ResourceStrategy resourceStrategy = new BasicResourceStrategyImpl();

  /**
   * Create a new Policy.
   *
   * @param baseUrl
   *          The base url that points to the resource that is being made available.
   * @param validUntil
   *          The date and time the resource is available until.
   * @param validFrom
   *          An optional date and time the resource will first become available.
   * @param clientIpAddress
   *          An optional client IP address to restrict the viewing of the resource to.
   * @param resourceStrategy
   *          The strategy for getting the resource from the policy.
   */
  private Policy(String baseUrl, DateTime validUntil, DateTime validFrom, String clientIpAddress) {
    requireNonNull(baseUrl);
    requireNonNull(validUntil);

    this.baseUrl = baseUrl;
    this.validUntil = validUntil;
    this.validFrom = Optional.fromNullable(validFrom);
    if (StringUtils.isNotBlank(clientIpAddress)) {
      this.clientIpAddress = Optional.of(InetAddresses.forString(clientIpAddress));
    } else {
      this.clientIpAddress = Optional.absent();
    }
  }

  /**
   * Create a {@link Policy} with only the required properties.
   *
   * @param baseUrl
   *          The url to the resource that will be signed.
   * @param validUntil
   *          The date and time the resource will be available until
   * @return A new {@link Policy} with the parameters set.
   */
  public static Policy mkSimplePolicy(String baseUrl, DateTime validUntil) {
    return new Policy(baseUrl, validUntil, null, null);
  }

  /**
   * Create a {@link Policy} with a date and time the resource will become available.
   *
   * @param baseUrl
   *          The url to the resource being signed.
   * @param validUntil
   *          The date and time the resource is available until.
   * @param validFrom
   *          The date and time the resource will become available.
   * @return A new {@link Policy} for limiting access to the resource.
   */
  public static Policy mkPolicyValidFrom(String baseUrl, DateTime validUntil, DateTime validFrom) {
    return new Policy(baseUrl, validUntil, validFrom, null);
  }

  /**
   * Create a {@link Policy} with the only ip address that will be allowed to view the resource.
   *
   * @param baseUrl
   *          The url to the resource being signed.
   * @param validUntil
   *          The date the resource will be available until.
   * @param ipAddress
   *          The ip of the client that will be allowed to view the resource.
   * @return A new {@link Policy} for limiting access to the resource.
   */
  public static Policy mkPolicyValidWithIP(String baseUrl, DateTime validUntil, String ipAddress) {
    return new Policy(baseUrl, validUntil, null, ipAddress);
  }

  /**
   * Create a {@link Policy} with both a date and time the resource will become available and a client ip address to
   * restrict it to.
   *
   * @param baseUrl
   *          The url to the resource that is being signed.
   * @param validUntil
   *          The date and time the resource will be available until.
   * @param validFrom
   *          The date and time the resource will become available.
   * @param ipAddress
   *          The ip of the client that will be allowed to view the resource.
   * @return A new {@link Policy} for limiting access to the resource.
   */
  public static Policy mkPolicyValidFromWithIP(String baseUrl, DateTime validUntil, DateTime validFrom,
          String ipAddress) {
    return new Policy(baseUrl, validUntil, validFrom, ipAddress);
  }

  /**
   * @return Get the url to the resource that is being signed with this policy.
   */
  public String getBaseUrl() {
    return baseUrl;
  }

  /**
   * @return Get the date this resource is valid until.
   */
  public DateTime getValidUntil() {
    return validUntil;
  }

  /**
   * @return Get the url for the resource in this {@link Policy}.
   */
  public String getResource() {
    return resourceStrategy.getResource(baseUrl);
  }

  /**
   * Set a new {@link ResourceStrategy} to transform the base url to a resource url.
   *
   * @param resourceStrategy
   *          The resource strategy to apply to transform the base url.
   */
  public void setResourceStrategy(ResourceStrategy resourceStrategy) {
    this.resourceStrategy = resourceStrategy;
  }

  /**
   * @return Get the optional ip address of the client that this resource will be restricted to.
   */
  public Optional<InetAddress> getClientIpAddress() {
    return clientIpAddress;
  }

  /**
   * @return Get the optional date and time this resource will become available.
   */
  public Optional<DateTime> getValidFrom() {
    return validFrom;
  }

}