←  response.scala 

package ru.circumflex
package web
import javax.servlet.http.HttpServletResponse
import collection.mutable.{ListBuffer, HashMap}
import java.lang.String
import java.util.Date

HTTP Response

The HttpResponse class provides functionality to prepare HTTP responses which will be sent to clients.

This class is designed to hold the response state, which then will be applied to actual HttpServletResponse using the flush method.

Since Circumflex is UTF-friendly it will implicitly set character encoding of response body to UTF-8. Feel free to change it if your application requires so.

 
class HttpResponse(val raw: HttpServletResponse) {

  def flush(): Nothing = {
    if (!raw.isCommitted) {
      if (statusCode != -1)
        raw.setStatus(statusCode)
      if (contentLength != -1)
        raw.setContentLength(contentLength)
      // apply headers
      headers.foreach {
        case (k: String, v: Date) => raw.setDateHeader(k, v.getTime)
        case (k: String, v: Int) => raw.setIntHeader(k, v)
        case (k: String, v) => raw.setHeader(k, v.toString)
      }
      // apply cookies
      cookies.foreach(c => raw.addCookie(c.convert()))
      // write response body
      body(raw)
      // flush
      raw.flushBuffer()
    }
    // throw an exception to the container
    throw new ResponseSentException()
  }

Response Basics

  • bufferSize returns or sets the size of response buffer;
  • contentType returns or sets the MIME type of the response, the default one is text/html (we are web framework after all!);
  • encoding returns or sets the name of the character encoding used in response body, as mentioned above, we implicitly set this to UTF-8;
  • statusCode returns or sets the status code of the response.
  • contentLength returns or sets the Content-Length header of the response.
 
  def bufferSize = raw.getBufferSize
  def bufferSize(bs: Int): this.type = {
    raw.setBufferSize(bs)
    this
  }
  def contentType = raw.getContentType
  def contentType(ct: String): this.type = {
    raw.setContentType(ct)
    this
  }
  def encoding = raw.getCharacterEncoding
  def encoding(e: String): this.type = {
    raw.setCharacterEncoding(e)
    this
  }
  protected var _statusCode: Int = -1
  def statusCode = _statusCode
  def statusCode(sc: Int): this.type = {
    _statusCode = sc
    this
  }
  protected var _contentLength: Int = -1   // -1 means that container's default will be used
  def contentLength = _contentLength
  def contentLength(cl: Int): this.type = {
    _contentLength = cl
    this
  }

  // set encoding and content type implicitly
  encoding("UTF-8")
  contentType("text/html")

Response Body

The body of the response is set by supplying a function which works with HttpServletResponse passed inside that function. The function is invoked inside the flush method when response is completely ready to be sent — this is done to avoid IllegalStateExceptions when working with response.

 
  protected var _body: HttpServletResponse => Unit = r => {}
  def body = _body
  def body(f: HttpServletResponse => Unit): this.type = {
    _body = f
    this
  }

Headers

Response headers contain operational information about the response. Circumflex Web Framework lets you access response headers via the headers object.

 
  object headers extends HashMap[String, Any] {
    update("X-Powered-By", "Circumflex 2.1.1")
  }

Cookies

The cookies field lets you set response cookies.

 
  val cookies = new ListBuffer[HttpCookie]

Helpers

Circumflex Web Framework includes following helpers to perform some common tasks:

  • set Content-Disposition header to attachment with specified filename using the attachment method;
  • set Pragma: no-cache, Cache-Control: no-store and Expires: 0 to disable client-side cache using noCache method.
 
  def attachment(filename: String): this.type = {
    headers("Content-Disposition") =
        "attachment; filename=\"" + new String(filename.getBytes("UTF-8"), "ISO-8859-1") + "\""
    this
  }

  def noCache(): this.type = {
    headers("Pragma") = "no-cache"
    headers("Cache-Control") = "no-store"
    headers("Expires") = 0l
    this
  }

}