org.scalatra.MethodOverride.scala Maven / Gradle / Ivy

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package org.scalatra

import org.scalatra.ServletCompat.http.{ HttpServletRequest, HttpServletRequestWrapper, HttpServletResponse }

import org.scalatra.servlet.ServletApiImplicits

import scala.collection.SortedSet

object MethodOverride {

  val ParamName: String = "_method"

  val HeaderName: SortedSet[String] = SortedSet(
    "X-HTTP-METHOD-OVERRIDE",
    "X-HTTP-METHOD",
    "X-METHOD-OVERRIDE")

}

/**
 * Mixin for clients that only support a limited set of HTTP verbs.
 * If the request is a POST and the `_method` request parameter is set,
 * the value of the `_method` parameter is treated as the request's method.
 */
trait MethodOverride extends Handler with ServletApiImplicits {

  abstract override def handle(req: HttpServletRequest, res: HttpServletResponse): Unit = {
    val req2 = req.requestMethod match {
      case Post => new HttpServletRequestWrapper(req) {
        override def getMethod(): String =
          methodOverride(req) getOrElse req.getMethod
      }
      case _ => req
    }
    super.handle(req2, res)
  }

  private[this] def methodOverride(req: HttpServletRequest) = {
    import org.scalatra.MethodOverride._
    val methodOpt = req.parameters get ParamName
    methodOpt orElse {
      val headers = req.headers
      val headerKeyOpt = headers.names.find { HeaderName contains _.toUpperCase() }
      headerKeyOpt.flatMap { req.headers get _ }
    }
  }

}