common/scala/src/main/scala/org/apache/openwhisk/core/entity/Secret.scala

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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.apache.openwhisk.core.entity

import spray.json._
import spray.json.DefaultJsonProtocol._

/**
 * Secret, a cryptographic string such as a key used for authentication.
 *
 * It is a value type (hence == is .equals, immutable and cannot be assigned null).
 * The constructor is private so that argument requirements are checked and normalized
 * before creating a new instance.
 *
 * @param key the secret key, required not null or empty
 */
protected[core] class Secret private (val key: String) extends AnyVal {
  protected[core] def asString: String = toString
  protected[entity] def toJson: JsString = JsString(toString)
  override def toString: String = key
}

protected[core] object Secret {

  /** Minimum secret length */
  private val MIN_LENGTH = 64

  /** Maximum secret length */
  private val MAX_LENGTH = 64

  /**
   * Creates a Secret from a string. The string must be a valid secret already.
   *
   * @param str the secret as string, at least 64 characters
   * @return Secret instance
   * @throws IllegalArgumentException is argument is not a valid Secret
   */
  @throws[IllegalArgumentException]
  protected[core] def apply(str: String): Secret = {
    require(str.length >= MIN_LENGTH, s"secret must be at least $MIN_LENGTH characters")
    require(str.length <= MAX_LENGTH, s"secret must be at most $MAX_LENGTH characters")
    new Secret(str)
  }

  /**
   * Creates a new random secret.
   *
   * @return Secret
   */
  protected[core] def apply(): Secret = {
    Secret(rand.alphanumeric.take(MIN_LENGTH).mkString)
  }

  implicit val serdes: RootJsonFormat[Secret] = new RootJsonFormat[Secret] {
    def write(s: Secret): JsValue = s.toJson
    def read(value: JsValue): Secret = Secret(value.convertTo[String])
  }

  private val rand = new scala.util.Random(new java.security.SecureRandom())
}