cache: Handle Last-Modified and If-Modified-Since.

This solves #13.

src/main/scala/com/lascala/http/HttpResponse.scala

@@ -17,47 +17,85 @@
  */
 package com.lascala.http
 
+import com.lascala.http.HttpConstants._
+
 import akka.util.{ ByteString, ByteStringBuilder }
-import HttpConstants._
+import java.io.File
+import org.apache.tika.Tika
+import java.io.FileInputStream
+import java.util.Date
+import java.util.Locale
+import java.text.SimpleDateFormat
+import java.util.TimeZone
 
 trait HttpResponse {
+  def lastModified: Date = null
   def body: ByteString
   def status: ByteString
   def reason: ByteString
   def mimeType: String
   def shouldKeepAlive: Boolean
 
-  // default charset to utf-8 for now but should be editable in the future
-  def contentType   = if (!mimeType.isEmpty) ByteString(s"Content-Type: ${mimeType}") else ByteString("")
+  def contentType   = ByteString(s"Content-Type: ${mimeType}")
   def cacheControl  = ByteString("Cache-Control: no-cache")
   def contentLength = ByteString(s"Content-Length: ${body.length.toString}")
 }
 
 object HttpResponse {
   val version = ByteString("HTTP/1.1")
-  val date = ByteString("Date: ")
   val server = ByteString("Server: lascala-http")
   val connection = ByteString("Connection: ")
   val keepAlive = ByteString("Keep-Alive")
   val close = ByteString("Close")
-
+  val date = ByteString("Date: ")
+  val lastModified = ByteString("Last-Modified: ")
+
+  def httpDateFormat = {
+    val dateFormat = new SimpleDateFormat(RFC1123_DATE_PATTERN, Locale.ENGLISH)
+    dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"))
+    dateFormat
+  }
+
+  def httpDate(date: Date) = ByteString(httpDateFormat.format(date))
+
   def bytes(rsp: HttpResponse) = {
     (new ByteStringBuilder ++=
     version ++= SP ++= rsp.status ++= SP ++= rsp.reason ++= CRLF ++=
-    (if(rsp.body.nonEmpty) rsp.contentType ++ CRLF else ByteString.empty) ++=
+    (if(rsp.body.nonEmpty || rsp.mimeType.nonEmpty) rsp.contentType ++ CRLF else ByteString.empty) ++=
     rsp.cacheControl ++= CRLF ++=
-    date ++= ByteString(new java.util.Date().toString) ++= CRLF ++=
+    date ++= httpDate(new Date) ++= CRLF ++=
+    Option(rsp.lastModified).map(lastModified ++ httpDate(_) ++ CRLF).getOrElse(ByteString("")) ++=
     server ++= CRLF ++=
     rsp.contentLength ++= CRLF ++=
     connection ++= (if (rsp.shouldKeepAlive) keepAlive else close) ++= CRLF ++= CRLF ++= rsp.body).result
   }
 }
 
+case class OKFileResponse(file: File, shouldKeepAlive: Boolean = true) extends HttpResponse {
+	def readFile(file: File) = {
+    val resource = new Array[Byte](file.length.toInt)
+    val in = new FileInputStream(file)
+    in.read(resource)
+    in.close()
+    ByteString(resource)
+  }
+  val body = readFile(file)
+  val mimeType = new Tika().detect(file)
+  val status = ByteString("200")
+  val reason = ByteString("OK")
+  override def lastModified = new Date(file.lastModified)
+}
+
 case class OKResponse(body: ByteString, shouldKeepAlive: Boolean = true, mimeType: String = "text/html") extends HttpResponse {
   val status = ByteString("200")
   val reason = ByteString("OK")
 }
 
+case class NotModifiedResponse(body: ByteString = ByteString.empty, shouldKeepAlive: Boolean = false, mimeType: String = "") extends HttpResponse {
+  val status = ByteString("304")
+  val reason = ByteString("Not Modified")
+}
+
 case class NotFoundError(body: ByteString = ByteString.empty, shouldKeepAlive: Boolean = false, mimeType: String = "") extends HttpResponse {
   val status = ByteString("404")
   val reason = ByteString("Not Found")
@@ -72,18 +110,3 @@ case class InternalServerError(body: ByteString = ByteString.empty, shouldKeepAl
   val status = ByteString("500")
   val reason = ByteString("Internal Server Error")
 }
-
-/**
- * HTTP 상수 모음
- */
-object HttpConstants {
-  val SP = ByteString(" ")
-  val HT = ByteString("\t")
-  val CRLF = ByteString("\r\n")
-  val COLON = ByteString(":")
-  val PERCENT = ByteString("%")
-  val PATH = ByteString("/")
-  val QUERY = ByteString("?")
-}
-
-

src/main/scala/common/main.scala

@@ -26,10 +26,9 @@ package common
 import akka.actor._
 import com.lascala.http._
 import com.lascala.http.HttpResponse._
+import com.lascala.http.HttpConstants._
 import akka.util.ByteString
 import java.io.File
-import org.apache.tika.Tika
-import java.io.FileInputStream
 
 /**
  * Sample Demo Application
@@ -43,24 +42,17 @@ object Main extends App {
 class RequestHandler extends Actor {
   val docroot = "."
 
-  def readFile(file: File) = {
-    val resource = new Array[Byte](file.length.toInt)
-    val in = new FileInputStream(file)
-    in.read(resource)
-    in.close()
-    ByteString(resource)
-  }
-
-  def mimeType(file: File) = new Tika().detect(file)
-
   def receive = {
-    case HttpRequest("GET", pathSegments, _, _, _, _) =>
+    case HttpRequest("GET", pathSegments, _, _, headers, _) =>
       new File(docroot, "/" + pathSegments.mkString(File.separator)) match {
         case file if file.isFile() =>
-          sender ! OKResponse(readFile(file), true, mimeType(file))
+          headers.find(_.name.toLowerCase == "if-modified-since") match {
+            case Some(d) if HttpResponse.httpDateFormat.parse(d.value).compareTo(new java.util.Date(file.lastModified)) != -1 => sender ! NotModifiedResponse()
+            case _ => sender ! OKFileResponse(file, true)
+          }
         case _ =>
-          sender ! NotFoundError
+          sender ! NotFoundError()
       }
-    case _ => sender ! MethodNotAllowedError
+    case _ => sender ! MethodNotAllowedError()
   }
 }