←  response.scala 

package ru.circumflex.web

import javax.servlet.http.HttpServletResponse
import org.apache.commons.io.IOUtils
import javax.activation.MimetypesFileTypeMap
import java.io._
import javax.servlet.ServletOutputStream
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 = {
    flush()
    throw new ResponseSentException
  }

  def flush(): Unit = 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
  }

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)
    return this
  }
  def contentType = raw.getContentType
  def contentType(ct: String): this.type = {
    raw.setContentType(ct)
    return this
  }
  def encoding = raw.getCharacterEncoding
  def encoding(e: String): this.type = {
    raw.setCharacterEncoding(e)
    return this
  }
  protected var _statusCode: Int = -1
  def statusCode = _statusCode
  def statusCode(sc: Int): this.type = {
    _statusCode = sc
    return 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
    return this
  }

  // set encoding implicitly
  encoding("UTF-8")

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
    return 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 2.0.1")
  }

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") + "\""
    return this
  }

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

}