org.coursera.naptime.router2.CollectionResourceRouter.scala Maven / Gradle / Ivy

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/*
 * Copyright 2016 Coursera Inc.
 *
 * Licensed 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.coursera.naptime.router2

import org.coursera.common.stringkey.StringKey
import org.coursera.common.stringkey.StringKeyFormat
import play.api.libs.json.Json
import play.api.mvc.Action
import play.api.mvc.BodyParser
import play.api.mvc.BodyParsers
import play.api.mvc.Request
import play.api.mvc.RequestHeader
import play.api.mvc.RequestTaggingHandler
import play.api.mvc.Result
import play.api.mvc.Results

import scala.concurrent.Future
import scala.language.existentials

object CollectionResourceRouter {

  private[naptime] def errorRoute(msg: String, resourceClass: Class[_]): RouteAction = {
    new Action[Unit] with RequestTaggingHandler {
      override def parser: BodyParser[Unit] = BodyParsers.parse.empty

      override def tagRequest(request: RequestHeader): RequestHeader =
        request.copy(tags = Map(Router.NAPTIME_RESOURCE_NAME -> resourceClass.getName))

      override def apply(request: Request[Unit]): Future[Result] = {
        // TODO(saeta): use standardized error response format.
        Future.successful(Results.BadRequest(Json.obj("msg" -> s"Routing error: $msg")))
      }
    }
  }

  case class StrictQueryParser[T](
      paramName: String,
      stringKeyFormat: StringKeyFormat[T],
      resourceClass: Class[_]) {

    def evaluate(rh: RequestHeader): Either[RouteAction, T] = {
      val queryStringResults = rh.queryString.get(paramName)
      if (queryStringResults.isEmpty || queryStringResults.get.isEmpty) {
        Left(errorRoute(s"Missing required parameter '$paramName'", resourceClass))
      } else if (queryStringResults.get.tail.isEmpty) {
        // Hack around broken iOS clients for namespace parameter. TODO(saeta): Remove on Feb 12
        val stringValue = if (paramName == "namespaces" &&
            queryStringResults.get.head.startsWith(",")) {
          queryStringResults.get.head.substring(1)
        } else {
          queryStringResults.get.head
        }
        val parsed = stringKeyFormat.reads(StringKey(stringValue))
        parsed.map { parsed =>
          Right(parsed)
        }.getOrElse {
          Left(errorRoute(s"Improperly formatted value for parameter '$paramName'", resourceClass))
        }
      } else {
        Left(errorRoute(s"Too many query parameters for '$paramName", resourceClass))
      }
    }
  }

  case class OptionalQueryParser[T](
      paramName: String,
      stringKeyFormat: StringKeyFormat[T],
      resourceClass: Class[_]) {
    def evaluate(rh: RequestHeader): Either[RouteAction, Option[T]] = {
      val queryStringResults = rh.queryString.get(paramName)
      if (queryStringResults.isEmpty || queryStringResults.get.isEmpty) {
        Right(None)
      } else if (queryStringResults.get.tail.isEmpty) {
        val stringValue = queryStringResults.get.head
        val parsed = stringKeyFormat.reads(StringKey(stringValue))
        parsed.map { parsed =>
          Right(Some(parsed))
        }.getOrElse {
          Left(errorRoute(s"Improperly formatted value for parameter '$paramName'", resourceClass))
        }
      } else {
        Left(errorRoute(s"Too many query parameters for '$paramName", resourceClass))
      }
    }
  }

  case class BooleanFlagParser(paramName: String, resourceClass: Class[_]) {
    def evaluate(rh: RequestHeader): Either[RouteAction, Boolean] = {
      val queryStringResults = rh.queryString.get(paramName)
      if (queryStringResults.isEmpty || queryStringResults.get.isEmpty) {
        Left(errorRoute(s"Missing required parameter '$paramName'", resourceClass))
      } else if (queryStringResults.get.tail.isEmpty) {
        val stringValue = queryStringResults.get.head
        stringValue match {
          case "true" => Right(true)
          case "false" => Right(false)
          case unknown: String =>
            Left(errorRoute(
              s"Improperly formatted value for parameter '$paramName'." +
                s" Expected 'true' or 'false' but found '$unknown'.",
              resourceClass))
        }
      } else {
        Left(errorRoute(s"Too many query parameters for '$paramName", resourceClass))
      }
    }
  }

  case class OptionBooleanFlagParser(paramName: String, resourceClass: Class[_]) {
    def evaluate(rh: RequestHeader): Either[RouteAction, Option[Boolean]] = {
      val queryStringResults = rh.queryString.get(paramName)
      if (queryStringResults.isEmpty || queryStringResults.get.isEmpty) {
        Right(None)
      } else if (queryStringResults.get.tail.isEmpty) {
        val stringValue = queryStringResults.get.head
        stringValue match {
          case "true" => Right(Some(true))
          case "false" => Right(Some(false))
          case unknown: String =>
            Left(errorRoute(
              s"Improperly formatted value for parameter '$paramName'. " +
                s"Expected 'true' or 'false' but found '$unknown'.",
              resourceClass))
        }
      } else {
        Left(errorRoute(s"Too many query parameters for '$paramName", resourceClass))
      }
    }
  }
  // TODO: build tolerant parser that doesn't error out the request if it can't parse
  // TODO: add a sequence parser that parses multiple copies of a flag.
}